JP2001128457A - Power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply capable of controlling input electric power and supplying a load with the electric power required. SOLUTION: A commercial power supply Vs is full-wave rectified by a rectifying circuit DB to obtain a ripple power supply. A discharge lamp La is provided as a load. One end of an inductor L0 is connected to the positive pole of the current output end of the rectifier circuit DB, and the other end to the connection point of switching elements Q1, Q2, which are turned on and off by control signals S1 to S4 from a control circuit. This control circuit has a steady-state control mode in which the switching elements Q1, Q4, Q2, Q3 arranged at the diagonal positions are turned on simultaneously, and those Q1, Q2, Q3, Q4 connected in series are each turned on and off alternately and an input power control mode in which the 'on-off' of only the switching element Q2 is stopped intermittently to control input electric power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply for supplying high-frequency AC power from a commercial power supply to a load.

[0002]

2. Description of the Related Art As a power supply device of this type used for a discharge lamp lighting device and the like, a circuit configuration shown in FIG. 30 has been proposed (Japanese Patent Publication No. 5-88067). The power supply device having the circuit configuration shown in FIG. 30 employs a configuration in which DC power obtained by rectifying commercial power Vs and performing DC-DC conversion is converted into high-frequency power by an inverter circuit INV.

The inverter circuit INV is a full-bridge type, in which a first series circuit in which a pair of switching elements Q3 and Q4 formed of bipolar transistors are connected in series, and a pair of switching elements Q1 and Q2 formed of bipolar transistors are connected in series. And a connected second series circuit, and both series circuits are connected in parallel to the smoothing capacitor C0. Diodes D1 to D4 are connected in antiparallel to the switching elements Q1 to Q4, respectively. Furthermore, both switching elements Q of the first series circuit
A load circuit Z is connected between a connection point between the switching elements Q3 and Q4 and a connection point between the switching elements Q1 and Q2 of the second series circuit. Here, the load circuit Z has a series circuit of an inductor L1 and a capacitor C1, and a discharge lamp La as a load is connected in parallel to the capacitor C1. That is,
The filament of the discharge lamp La is inserted between the inductor L1 and the capacitor C1 and between the connection point of the switching elements Q3 and Q4 and the capacitor C1.

The switching elements Q1 to Q4 are turned on and off by the output of a control circuit 10 'shown in FIG. The control circuit 10 'mainly includes an astable multivibrator including transistors Tr2 and Tr3, capacitors C11 and C12 for determining an oscillation cycle, resistors R11 and R12, and output resistors R13 and R14. As a result, the transistors Tr1 and Tr4 are switched at a high frequency (frequency sufficiently higher than the frequency of the commercial power supply AC). Further, each transistor Tr
1 and Tr4 have pulse transformers PT1 and PT2, respectively.
Are connected in series, and each pulse transformer PT1,
Switching elements Q1 to Q4 are controlled by outputs of two secondary windings provided in PT2. The terminals a and b in FIG. 31 are connected to the power supply (both ends of the smoothing capacitor C0) of the inverter circuit INV, and the terminals c, c ', d, and
d ', e, e', f, f 'are respectively connected to the base-emitter of each of the switching elements Q1 to Q4. Here, the terminals c ′, d ′, e ′,
f 'is connected to the emitter. The terminals c and c 'are the switching element Q1, the terminals d and d' are the switching element Q4, the terminals e and e 'are the switching element Q2, the terminals f and
f 'corresponds to the switching element Q3. Therefore, the switching elements Q1 to Q4 constituting the inverter circuit INV are connected in series at the diagonal positions (ie, between both ends of the smoothing capacitor C0 through the series circuit of the inductor L1 and the capacitor C1) without being simultaneously turned on. ) Are controlled to be turned on at the same time.

With the above arrangement, the switching element Q
There is provided a period in which the switching elements Q1 and Q4 are simultaneously turned on and a period in which the switching elements Q2 and Q3 are simultaneously turned on. . The switching of the voltage polarity and the resonance operation of the resonance circuit cooperate to apply a high-frequency AC voltage to the discharge lamp La. Here, the on / off frequency of the switching elements Q1 to Q4 is set higher than the resonance frequency of the load circuit Z including the inductor L1, the capacitor C1, and the discharge lamp La.
The current flowing through the load circuit Z includes switching elements Q1 to Q4.
Lags the phase of the switching. That is, it is operated in a so-called slow mode.

The rectifier circuit DB for rectifying the commercial power Vs is composed of a diode bridge.
Is inserted. An inductor L0 is inserted between the positive electrode of the DC output terminal of the rectifier circuit DB and the connection point of the switching elements Q1 and Q2.

Therefore, during the period in which the low-voltage side switching element Q2 of the switching elements Q1 and Q2 connected in series is on, the inductor L0
Current flows in the inductor L0, and electromagnetic energy is accumulated in the inductor L0. The switching elements Q1 and Q2 are alternately turned on and off, and when the switching element Q2 is turned off, the added voltage of the output voltage (pulsating voltage) of the rectifier circuit DB and the voltage across the inductor L0 is applied to the smoothing capacitor C0. During a period higher than the voltage between both ends, the energy accumulated in the inductor L0 is released through the path of the inductor L0-diode D1-smoothing capacitor C0-rectifier circuit DB-inductor L0, and the smoothing capacitor C0 is charged at this time. That is, the voltage across the smoothing capacitor C0 is boosted higher than the output voltage of the rectifier circuit DB, and the switching element Q2, the diode D1, the inductor L0, and the smoothing capacitor C0 form a boosting chopper circuit. In other words, the switching element Q2 is used for both the inverter circuit INV and the boost chopper circuit.

The operation of the circuit shown in FIG. 30 will be described below with reference to FIGS. The operation shown in FIG. 32 shows an operation during a period of about the switching cycle of the switching elements Q1 to Q4, and FIG. 33 shows an operation during a period about the cycle of the commercial power supply Vs.

Immediately after the power is turned on, the rectifier circuit DB
, A charging current flows to the smoothing capacitor C0 through the inductor L0 and the diode D1. Smoothing capacitor C
When 0 is charged to some extent and the operation of the control circuit 10 becomes possible, the switching elements Q1 to Q4 are switched, and the smoothing capacitor C0 is intermittently charged at a high frequency by the switching of the switching element Q2 as described above. FIG. 32A shows ON / OFF of the switching element Q2. When the switching element Q2 is ON during the period t0-t1, a current flows from the rectifier circuit DB through the inductor L0 as shown in FIG. 32F. During this period, the passing current IDC of the inductor L0 increases with time. Further, the increase rate of the current passing through the inductor L0 changes according to the voltage change within one cycle of the commercial power supply Vs. That is, near the peak voltage of the commercial power supply Vs, the passing current IDC of the inductor L0 changes as shown by the solid line in FIG. 32 (f), and changes as shown by a two-dot chain line in accordance with the voltage value of the commercial power supply Vs. The collector current IC2 of the switching element Q2 (see FIG. 32B) is the inductor L0.
And the oscillating current I flowing through the load circuit Z.
It becomes a combined current with z.

When the switching element 2 is turned off at the time t1, the energy stored in the inductor L0 is released, so that a current flows through the diode D1.
The oscillating current I flowing through the load circuit Z is connected to the diode D1.
Since z also flows, a current ID1 as shown in FIG. 32E flows through the diode D1. During this time, the smoothing capacitor C0
Is charged. The current ID1 flowing through the diode D1 changes in accordance with the voltage value of the commercial power supply Vs, similarly to the passing current IDC of the inductor L0. ). Time t
In No. 2, although the switching element Q2 is still off, the release of the energy of the inductor L0 ends, so that a current flows through the load circuit Z from the smoothing capacitor C0 through the switching element Q1. That is, the collector of the switching element Q1 is applied to the collector of FIG.
Current IC having a partial sine wave as shown in FIG.
1 flows.

At time t3, switching element Q2 conducts again, and current IC1 stops flowing through switching element Q1. However, since the switching of the switching elements Q1 to Q4 is in the slow mode, the switching element Q1
The switching element Q1 is turned off while the current IC1 is flowing through the load circuit Z, and an oscillating current flowing through the load circuit Z flows through the diode D2 after time t3. That is, FIG.
As shown in (c), the current ID2 flows through the diode D2.
When the oscillating current stops flowing at time t4 during the period when the switching element Q2 is on, the operation after time t0 is repeated. That is, the operation from time t0 to time t4 is one cycle, and a sinusoidal oscillation current Iz flows through the load circuit Z as shown in FIG.

Since the switching elements Q1 to Q4 operate as shown in FIG. 32, if the voltage Vin of the commercial power supply Vs changes as shown in FIG.
The current IDC flowing through the inductor L0 has a high frequency and does not alternate as shown in FIG. 33B, and has a pulsating envelope. As described above, since the filter circuit F for blocking high frequency is inserted between the commercial power supply Vs and the rectifier circuit DB, the input current Iin to the filter circuit F is changed to the commercial power supply Vs as shown in FIG. Is substantially proportional to the voltage waveform of FIG. That is, the harmonic current distortion is small and a high power factor can be obtained. On the other hand, the voltage Vdc across the smoothing capacitor C0 is shown in FIG.
3D, the output voltage of the inverter circuit INV (the voltage between the connection point of the switching elements Q1 and Q2 and the connection point of the switching elements Q3 and Q4) VRF is shown in FIG. The envelope becomes an almost constant high-frequency voltage as shown in FIG.

As described above, in the power supply device having the circuit configuration shown in FIG. 30, a part of the switching element Q2 constituting the inverter circuit INV is also used as the switching element of the boost chopper circuit, and the diode D1 is also used. Since DC-DC conversion is performed, the generation of harmonic current distortion can be suppressed and a high input power factor can be maintained by the step-up chopper circuit. In addition, the number of components is reduced due to the dual use of elements, thereby reducing costs. And the circuit configuration is simplified.

By the way, a power supply having a configuration shown in FIG. 34 is also known (Japanese Patent No. 2690045 and US Pat. No. 5,063,490). Although the configuration shown in FIG. 34 also constitutes a full-bridge type inverter circuit INV, switching elements Q1 to Q4 have power MO
An SFET is used. When a bipolar transistor is used for the switching elements Q1 to Q4, a diode D
Although 1 to D4 are connected in anti-parallel, the diodes D1 to D4 do not have to be provided since the MOSFET has a body diode. In FIG. 34, the body diodes are shown as diodes D1 to D4. That is, the power supply device shown in FIG. 34 has a first series circuit in which a pair of switching elements Q1 and Q2 formed of a power MOSFET are connected in series, and a first series circuit in which a pair of switching elements Q3 and Q4 formed of a power MOSFET are connected in series. And two series circuits are connected in parallel to the smoothing capacitor C0. Also, both switching elements Q1,
Q2 and both switching elements Q of the second series circuit
A load circuit Z composed of an inductor L1, a capacitor C1, and a discharge lamp La is connected between the connection point of 3 and Q4. That is, the configurations of the inverter circuit INV and the load circuit Z are equivalent to the configuration shown in FIG.

However, in the configuration example shown in FIG. 30, the commercial power supply Vs is full-wave rectified by the rectifier circuit DB composed of a diode bridge via the filter circuit F.
In the configuration example shown in FIG. 34, two diodes D01 and D0
2 connected in series in the forward direction.
0, and the other end of the inductor L0, one end of which is connected to the connection point between the diodes D01 and D02, is connected to one output terminal of the filter circuit F. The other output terminal of the filter circuit F is connected to a connection point between the switching elements Q1 and Q2. The diodes D01 and D02 are connected to the polarities of a diode bridge together with the diodes D1 and D2.

Each of the switching elements Q1 to Q4 is controlled by a control circuit (not shown) in the same manner as the switching elements Q1 to Q4 of the circuit shown in FIG. That is, each of the two switching elements Q1, Q2, Q3, Q4 has a high frequency (a frequency sufficiently higher than the frequency of the commercial power supply Vs).
Are turned on and off alternately by the switching element Q at the diagonal position.
1, Q4, Q2, and Q3 are controlled to be turned on at the same time.

The operation of the circuit shown in FIG. 34 will be briefly described below. During a period during which the voltage Vin of the commercial power supply Vs is positive (in FIG. 34, the direction of the arrow of Vin is positive, and hereinafter, this period is referred to as a “positive half cycle”), the switching elements Q1 and Q4 Is on, the commercial power supply Vs-the inductor L0-the diode D0
1-switching element Q1-current flows through the path of commercial power supply Vs, and smoothing capacitor C0-switching element Q
Current also flows through the path of 1-load circuit Z-switching element Q4-smoothing capacitor C0. The value of the current passing through the inductor L0 increases in proportion to the voltage Vin (instantaneous value) of the commercial power supply Vs. When the switching elements Q1 and Q4 are turned off, the electromagnetic energy stored in the inductor L0 is transferred to the inductor L0-diode D01-smoothing capacitor C0-
The diode D2 is discharged through the path of the commercial power supply Vs and the inductor L0, and is used for charging the smoothing capacitor C0.
By this operation, the switching element Q1 of the inverter circuit INV is also used as a switching element of the boost chopper circuit, similarly to the configuration shown in FIG.

Since the switching elements Q2 and Q3 are turned on as the switching elements Q1 and Q4 are turned off, when the charging of the smoothing capacitor C0 is completed, the smoothing capacitor C0 is used as a power supply and the smoothing capacitor C0-switching element is turned off. Q3-Load circuit Z-Switching element Q
In FIG. 34, the load circuit Z is connected to the
The current flows to the left of.

On the other hand, during the negative half cycle of the commercial power supply Vs, during the ON period of the switching elements Q2 and Q3,
Commercial power supply Vs-switching element Q2-diode D0
Electromagnetic energy is accumulated in the inductor L0 by flowing a current through the path of (2-inductor L0-commercial power supply Vs). This electromagnetic energy is applied to the switching elements Q2, Q2
3 turns off, inductor L0-commercial power supply Vs-diode D1-smoothing capacitor C0-diode D02
-Smoothing capacitor C is discharged through the path of inductor L0.
Used to charge 0. Also, in the negative half cycle, an AC voltage is applied to the load circuit Z using the smoothing capacitor C0 as a power supply. In short, in the negative half cycle, the switching element Q2 of the inverter circuit INV is also used as the switching element of the boost chopper circuit.

In the configuration shown in FIG. 34, the switching elements Q1 and Q2 of the switching elements Q1 to Q4 of the inverter circuit INV are also used as the switching elements of the boost chopper circuit, so that the number of parts is small and the circuit configuration is simple. And the power consumption is reduced, and the switching elements Q1 to Q
4, the switching elements Q1 and Q2 which are also used as switching elements of the step-up chopper circuit differ in the positive and negative half cycles, so that the stress caused by sharing the two functions is distributed to the two switching elements Q1 and Q2. As a result, stress is reduced. Further, since the power loss of the switching elements Q1 and Q2 is balanced, the heat dissipation structure of the switching elements Q1 and Q2 can be made the same. Further, the switching element Q
Since Q1 and Q2 are also used as switching elements of the boost chopper circuit, there is no need to provide a separate drive circuit for the boost chopper circuit, and the configuration of the drive circuit is simplified.

In the circuit shown in FIG. 34, a part of the electromagnetic energy stored in the inductor L0 is also discharged through the load circuit Z without being used for charging the smoothing capacitor C0. As a result, when the power consumption in the load circuit Z decreases, surplus energy is used for charging the smoothing capacitor C0, and the voltage Vdc across the smoothing capacitor C0 increases excessively.

However, since the switching elements Q1 and Q2 are shared by the inverter circuit INV and the boost chopper circuit, the control state of the inverter circuit INV (the switching frequency of the switching elements Q1 to Q4 and the Changing the duty) affects the operation of the boost chopper circuit, and conversely, the control state of the boost chopper circuit (switching frequency and on-duty of the switching elements Q1 and Q2) to control the input power.
Is changed, this also affects the inverter circuit INV, and the degree of freedom in controlling the switching elements Q1 to Q4 is reduced.

Therefore, the voltage V across the smoothing capacitor C0 is
In order to suppress the rise of dc, it is conceivable that the on / off of the switching element Q1 is intermittently stopped in the positive half cycle of the commercial power supply Vs, and the on / off of the switching element Q2 is intermittently stopped in the negative half cycle. ing.
That is, means for detecting the voltage polarity of the commercial power supply Vs is provided, and control is performed as shown in FIG. FIG. 35A shows the commercial power supply V
s, and the broken line in FIG.
s, the solid line indicates the current ICH flowing through the inductor L0, and the dashed line indicates the envelope of the current flowing through the inductor L0. As described above, the current flows through the inductor L0 at a high frequency, and its envelope becomes sinusoidal. Therefore, as shown by the broken line, the current input through the filter circuit F has a sine wave substantially proportional to the voltage Vin of the commercial power supply Vs. It has a wave-like waveform, has less harmonic current distortion, and can obtain a relatively high input power factor. FIGS. 35C and 35D show control signals S1 and S2 from a control circuit for turning on and off the switching elements Q1 and Q2, respectively. In the positive half cycle, the switching element Q1 is also used as the boost chopper circuit, so that the switching element Q1 is intermittently stopped. In the negative half cycle, the switching element Q2 is also used as the boost chopper circuit, so that the switching element Q2 is used intermittently. To stop. Such an operation prevents the voltage Vdc across the smoothing capacitor C0 from being excessively boosted (ie,
The input power from the commercial power supply Vs can be freely reduced), and the envelope of the lamp current Ila of the discharge lamp La can be kept almost constant as shown in FIG.

[0024]

By the way, the above-mentioned 2
In one power supply device, a part of the switching elements Q1 to Q4 forming the inverter circuit INV is also used as a boost chopper circuit, and the voltage Vdc across the smoothing capacitor C0 is increased by the output fluctuation of the discharge lamp La as a load. In such a case, a switching element that is also used as a boost chopper circuit and a switching element that is located at a diagonal position of the switching element (the switching element Q1
When the switching element Q4 is also used, the switching element Q3) is intermittently stopped when the switching element Q2 is also used for the step-up chopper circuit. However, as shown in FIG. Since the lamp current Ila flowing through the lamp intermittently stops, there is a problem that the load power is reduced.

When the load circuit Z includes a discharge lamp La having a hot cathode such as a fluorescent lamp, a preheating period in which the filament of the discharge lamp La is preheated from the time the power is turned on until the lamp is turned on (a preheating period). Is necessary, and the power consumption in the load circuit Z during the preheating period is very small compared to the power consumption after lighting. (Operation as shown in FIG. 35). As a result, the electric power input from the commercial power supply Vs is reduced, so that the charging of the smoothing capacitor C0 is difficult to proceed and the preheating period is prolonged.

In recent years, high-output fluorescent lamps have been developed for the purpose of resource saving and energy saving. Such fluorescent lamps have a small tube diameter of 18 to 19 mm and an optical path length of 1,400.
2,500 mm. As this type of fluorescent lamp, for example, as shown in FIG. 36, two annular light emitting tubes 1 and 1 having a filament 2 at one end and a closed portion 3 at the other end are arranged concentrically. The vicinity of the closed portion 3 of the two annular arc tubes 1 is joined by a bridge joint 4 to form one discharge path therein, and a base 5 surrounding one end and the other end of the annular arc tube 1 is provided. Some have been done. In this fluorescent lamp, the coldest point is formed in the closed portion 3. In this type of fluorescent lamp, the tube diameter is reduced in order to increase the lamp efficiency, and the inner diameter of the tube is smaller than that of a conventional fluorescent lamp, so that the lamp current is relatively small and the lamp voltage is high.

Such a fluorescent lamp needs to use a small filament because the tube diameter is smaller than that of the conventional fluorescent lamp. However, since the discharge path is long, sufficient preheating is required before lighting. The ratio between the preheating current flowing through the filament and the current flowing through the filament during lighting is larger than that of the conventional fluorescent lamp. That is, when such a highly efficient fluorescent lamp having a small tube diameter and a large optical path length is used, the preheating current in the preheating period must be increased. Since sufficient power cannot be supplied to the load circuit Z for a relatively long period, when a highly efficient fluorescent lamp is used, it is more difficult to secure a preheating current during the preheating period. It is necessary to control the preheating current with high precision in order to prevent the filament from breaking.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a power supply device capable of controlling input power and stably supplying required power to a load.

[0029]

According to a first aspect of the present invention, there is provided a switching device having a smoothing capacitor and a diode connected between both ends of the smoothing capacitor and connected in antiparallel to each other. , A second series circuit in which a pair of switching elements having diodes connected between both ends of the smoothing capacitor and connected in antiparallel to each other are connected in series, an LC resonance circuit and A load circuit connected between a connection point of each of the pair of switching elements including a load and constituting each of the first and second series circuits, wherein a commercial circuit is provided between both ends of at least one switching element of the first series circuit. A pulsating power source obtained by rectifying the power source is connected via an inductor, and has a period in which switching elements at diagonal positions are simultaneously turned on, and And a steady-state control mode in which a pair of switching elements constituting the second series circuit are alternately turned on and off, and a pair of switching elements constituting the second series circuit are alternately turned on and off, and Input power control having a period in which the pulsating power supply intermittently stops on / off of the switching element connected between both ends and the other switching element of the first series circuit is simultaneously turned on at the same time as the switching element at the diagonal position. And a switching element having a pulsating power supply connected between both ends thereof forms a part of the boost chopper circuit together with the inductor, thereby reducing input current distortion. By operating in the input power control mode even if the power required for the power supply changes, the switching element connected between By intermittently stopping the power supply, the period during which the input current from the commercial power supply flows is reduced, and the voltage across the smoothing capacitor can be prevented from being excessively boosted, and the switching element connected between both ends of the pulsating power supply can be prevented. Since the resonance current can be continuously supplied to the load circuit by turning on and off the switching element at the diagonal position, the power supplied to the load circuit can be controlled while controlling the input power, and the voltage across the smoothing capacitor can be controlled. Can be set to an appropriate value, and the required power can be stably supplied to the load.

According to a second aspect of the present invention, in the first aspect, a pulsating power source obtained by rectifying a commercial power source is connected between both ends of one switching element of the first series circuit via an inductor. One of the switching elements forms a part of the step-up chopper circuit and can have a function of improving input current distortion.

According to a third aspect of the present invention, in the first aspect of the present invention, a pulsating power source obtained by rectifying a commercial power source is connected between both ends of each switching element of the first series circuit via an inductor. In the mode, since the switching elements in which the commercial power supply is stopped during the positive half cycle and the negative half cycle are different, each switching element of the first series circuit forms a part of the step-up chopper circuit and the input current. A function to improve distortion can be provided.

According to a fourth aspect of the present invention, there is provided a first series circuit in which a smoothing capacitor, a pair of switching elements having a diode connected between both ends of the smoothing capacitor and connected in antiparallel to each other are connected in series, A second series circuit in which a pair of switching elements having diodes connected between both ends of the capacitor and connected in antiparallel to each other are connected in series; and a first and a second series circuit each including an LC resonance circuit and a load. A load circuit connected between the connection points of each pair of switching elements, and a pulsating power supply obtained by rectifying a commercial power supply between both ends of at least one switching element of the first series circuit is connected via an inductor; Each pair of switches constituting the first and second series circuits has a period during which the switching elements at diagonal positions are simultaneously turned on. And a pair of switching elements forming a first and a second series circuit having a period in which a switching element at a diagonal position is simultaneously turned on and a pair of switching elements constituting a first and second series circuit being alternated. And an input power control mode for controlling the on-duty of a switching element connected between both ends of the pulsating power supply of the first series circuit. The connected switching element forms a part of the step-up chopper circuit together with the inductor, thereby reducing the input current distortion.Also, by operating in the input power control mode even when the power required for the load changes, The input from the commercial power supply is controlled by controlling the on-duty of the switching element connected between both ends of the pulsating power supply to be small. The period in which the current flows is reduced, and the voltage across the smoothing capacitor can be prevented from being excessively boosted. Power supply to the load circuit while controlling the input power, the voltage across the smoothing capacitor can be set to an appropriate value, and the required power to the load can be controlled. Can be supplied stably.

According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, a control circuit for turning on / off each switching element is provided, and the control circuit pulsates according to the magnitude of the voltage value across the smoothing capacitor. Since the voltage across the smoothing capacitor is controlled to a substantially set value by changing the number of times that the switching element to which the power supply is connected is turned on within a predetermined period, the voltage across the smoothing capacitor is controlled to an appropriate value with good controllability. Can be controlled.

According to a sixth aspect of the present invention, in the first to fourth aspects of the present invention, a control circuit for turning on and off each switching element is provided, and the control circuit pulsates according to the magnitude of the voltage value across the smoothing capacitor. Since the voltage across the smoothing capacitor is controlled to a substantially set value by changing the on-duty of the switching element to which the power supply is connected, the voltage across the smoothing capacitor can be controlled to an appropriate value with good controllability.

According to a seventh aspect of the present invention, in the first to fourth aspects of the present invention, a control circuit for turning on and off each switching element is provided. Since the voltage across the smoothing capacitor is controlled to a substantially set value by changing the operating frequency of the switching element to which the power supply is connected, the voltage across the smoothing capacitor can be controlled to an appropriate value with good controllability. .

According to an eighth aspect of the present invention, in the first to fourth aspects of the present invention, a control circuit for turning on / off each switching element is provided, and the control circuit includes an effective value, an instantaneous value, and a peak value of the pulsating power supply. The voltage across the smoothing capacitor is controlled to a substantially set value by controlling the operation of the switching element to which the pulsating power supply is connected in accordance with one size, so that the voltage across the smoothing capacitor is adjusted to an appropriate value. Control can be performed with good controllability.

According to a ninth aspect of the present invention, in the first to fifth aspects of the present invention, a control circuit for turning on and off each switching element is provided, and the control circuit controls the operation of the switching element on the side to which the pulsating power supply is connected. When the voltage across the smoothing capacitor is controlled to a substantially set value by switching, when the voltage across the smoothing capacitor reaches a first predetermined value, the side to which the pulsating power supply is connected so as to suppress the rise of the voltage across the smoothing capacitor. When the voltage across the smoothing capacitor reaches a second predetermined value, the operation of the switching element to which the pulsating power supply is connected is switched so that the voltage across the smoothing capacitor rises. Hysteresis can be added to the voltage for switching the operation of the connected switching element, or malfunction due to noise can be prevented. Can not, it can be controlled with good controllability of the voltage across the smoothing capacitor to the appropriate value.

According to a tenth aspect of the present invention, in the first to fifth aspects, a control circuit for turning on / off each switching element is provided, and the control circuit makes a voltage value across the smoothing capacitor reach a predetermined value after power-on. During this period, the number of times the switching element on the side connected to the pulsating power supply is turned on within a certain period of time is changed according to the magnitude of the voltage value across the smoothing capacitor to substantially reduce the voltage across the smoothing capacitor to a set value. , The voltage across the smoothing capacitor can be increased to a desired voltage value in a relatively short time, and stable and highly reliable operation can be performed.

According to an eleventh aspect of the present invention, in the first to fifth aspects of the present invention, a control circuit for turning on and off each switching element is provided, and the control circuit is connected to a pulsating power supply in accordance with an elapsed time from power-on. Since the voltage between both ends of the smoothing capacitor is controlled to a substantially set value by controlling the operation of the switching element on the side that is being set, the voltage between both ends of the smoothing capacitor can be increased to a desired voltage value in a relatively short time, Stable and highly reliable operation becomes possible.

According to a twelfth aspect of the present invention, in accordance with the first to fifth aspects of the present invention, a control circuit for turning on / off each switching element is provided, and the control circuit makes a voltage value across the smoothing capacitor reach a predetermined value after power-on. During this period, the number of on-duties and the on-duty of the switching element to which the pulsating power supply is connected are changed according to the magnitude of the voltage value across the smoothing capacitor to change the voltage across the smoothing capacitor. Since the voltage is controlled to a substantially set value, the voltage between both ends of the smoothing capacitor can be increased to a desired voltage value in a relatively short time, and stable and highly reliable operation can be performed.

According to a thirteenth aspect of the present invention, in the first to twelfth aspects, since the load is a discharge lamp, an appropriate voltage across the smoothing capacitor is obtained irrespective of the state of the discharge lamp during a preheating period or after lighting. The power required for the discharge lamp can be supplied stably.

According to a fourteenth aspect, in the thirteenth aspect, the discharge lamp has a rated lamp power of about 97 W, a rated lamp current of about 0.43 A, and a lamp voltage of about 229 V.
Since the ring-shaped fluorescent lamp described above, the power required for such a high-output fluorescent lamp can be stably supplied, and the high-output fluorescent lamp can be stably turned on.

According to a fifteenth aspect, in the thirteenth aspect, the discharge lamp has a rated lamp power of about 68 W, a rated lamp current of about 0.43 A, and a lamp voltage of about 160 V.
Since the ring-shaped fluorescent lamp described above, the power required for such a high-output fluorescent lamp can be stably supplied, and the high-output fluorescent lamp can be stably turned on.

According to a sixteenth aspect, in the thirteenth aspect, the discharge lamp has an optical path length of about 1400 to 2500.
mm and a tube diameter of about 18 to 29 mm, it is possible to stably supply power required for such a discharge lamp having a long optical path length, and to stably light the lamp.

[0045]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) The basic configuration of a power supply device according to this embodiment is substantially the same as the conventional configuration shown in FIG. 30, and as shown in FIG. A first series circuit in which Q1 and Q2 are connected in series and a second series circuit in which a pair of switching elements Q3 and Q4 made of MOSFETs are connected in parallel, and both switching elements of the first series circuit are connected. Q3
Q4 and both switching elements Q of the second series circuit
It has a full-bridge type inverter circuit INV in which a load circuit Z is connected between the connection point of the inverter circuit 1 and the connection point of Q2. First
Is connected to the smoothing capacitor C0.
Are connected in parallel. In FIG. 1, diodes D1 to D4 connected in anti-parallel to the switching elements Q1 to Q4 respectively include power MOSFETs Q1 to Q4.
4 shows a body diode No. 4.

The load circuit Z has a series circuit of a capacitor C1, an inductor L1, and a DC cut capacitor Cc, and a discharge lamp La serving as a load is connected to the capacitor C1 in parallel. Although the filament of the discharge lamp La is omitted in FIG. 1, the capacitor C1 is actually connected to one end of the filament of the discharge lamp La on the non-power supply side, similarly to the conventional configuration shown in FIG. Connected between them.

The commercial power supply Vs is input to a rectifier circuit DB via a high frequency blocking filter circuit F to be full-wave rectified. Here, a pulsating power source is obtained by full-wave rectifying the commercial power source Vs by the rectifier circuit DB. One end of an inductor L0 is connected to the positive DC output terminal of the rectifier circuit DB, and the other end of the inductor L0 is connected to a switching element Q.
1 and Q2. That is, a series circuit of the inductor L0 and the switching element Q2 is connected between the DC output terminals of the rectifier circuit DB. Note that the rectifier circuit DB includes a diode bridge including diodes D5 to D8. The filter circuit F is provided to prevent high frequency current from leaking from the inverter circuit INV to the commercial power supply Vs.

The switching elements Q1 to Q4 are turned on and off by control signals S1 to S4 from a control circuit (not shown). In the present embodiment, the control circuit has a period during which the switching elements Q1, Q4, Q2, Q3 at the diagonal positions are simultaneously turned on, and each pair of switching elements constituting the first and second series circuits, respectively. Q1, Q2, Q3
A steady control mode in which Q4s alternately turn on and off;
Of a pair of switching elements Q3 and Q
4 are alternately turned on and off, and the switching element Q2 (the switching element connected between the DC output terminals of the rectifier circuit DB, that is, the switching element used also as the boost chopper circuit) of the first series circuit is intermittently turned on and off. And an input power control mode having a period during which the switching element Q1 is turned on simultaneously with the switching element Q4 at the diagonal position. That is, in the input power control mode, the switching element Q3 is alternately turned on and off with the switching element Q4 even during the period when the on / off of the switching element Q2 is stopped. In other words, the present embodiment is similar to the conventional example shown in FIG. 34 in that the switching element Q2 serving as the chopper is intermittently stopped for input power control, but the switching element Q2 is intermittently turned on and off. The feature is that the switching element Q3 at the diagonal position of the switching element Q2 also keeps on and off complementarily to the switching element Q4 during the stop period.

First, the operation in the steady control mode will be described with reference to FIGS.

In FIG. 2, the illustration of the filter circuit F and the DC cut capacitor Cc is omitted, and the on / off of each of the switching elements Q1 to Q4 is represented by whether the two end points are short-circuited or opened, and are connected in anti-parallel. The state in which the current flows through the diodes D1 to D4 is indicated between the end points of the diodes D1 to D4 through which the current flows. Also,
Sections a to g in FIG. 3 correspond to FIGS. 2A to 2G. A broken line with an arrow in FIG. 2 indicates a current path. FIG. 3A shows ON / OFF of the switching elements Q1 and Q4,
(B) shows ON / OFF of the switching elements Q2 and Q3,
(C) shows the current IL1 flowing in the inductor L1, (d) shows the current IL0 flowing in the inductor L0, and (e) shows the waveform of the current IC0 flowing in the smoothing capacitor C0. The currents IL1, IL0, and IC0 have the positive directions of the arrows in FIG.

As shown in FIGS. 3A and 3B,
Between the on-periods of the switching elements Q1 and Q4 and the on-periods of the switching elements Q2 and Q3, a pause period for turning off all the switching elements Q1 to Q4 is provided. By providing such a pause period, two switching elements Q1, Q2,
Q3 and Q4 (switching elements of each arm of the full bridge configuration) are simultaneously turned on to reliably prevent short-circuit between both ends of the smoothing capacitor C0. Also, a pair of switching elements Q1, Q4, Q provided at diagonal positions
2, Q3 are simultaneously turned on and off.

Now, assuming that a steady operation is performed, the switching element Q as shown in FIGS.
1, Q4 and the switching elements Q2, Q3 are turned on and off alternately, and after the switching elements Q1, Q4 are turned off, a period a (all the switching elements Q1 to Q4 are turned off) until the switching elements Q2, Q3 are turned on. period)
, When the switching element Q1, Q4 at time t ₁ is turned off, the inductor by holding current of the inductor L1 as shown in FIG. 2 (a) L1- diode D3- smoothing capacitor C0- diode D2- the discharge lamp La and capacitor C1- A current flows on the path of the inductor L1, and at the same time, a current also flows on the path of the commercial power supply Vs-rectifier circuit DB-discharge lamp La and capacitor C1-inductor L1-diode D3-smoothing capacitor C0-rectifier circuit DB-commercial power supply Vs. That is, during this period a, the current is drawn from the commercial power supply Vs, and the current IL0 also flows through the inductor L0 as shown in FIG. 3D, and the charging current IC0 flows through the smoothing capacitor C0 as shown in FIG. Flows.

Next, at time t2, switching element Q2
Immediately after Q3 is turned on, a period b during which the holding current of the inductor L1 flows as shown in FIG.
2), the inductor L1-switching element Q3-smoothing capacitor C0-switching element Q2-discharge lamp La and capacitor C1 as shown in FIG.
-Path of inductor L1 and commercial power supply Vs-rectifier circuit D
A current flows through a path of B-inductor L0-switching element Q2-rectifier circuit DB-commercial power supply Vs. During this period b, the current I flowing through the inductor L0 as shown in FIG.
L0 increases. Further, since the charging current IC0 of the smoothing capacitor C0 flows by the holding current of the inductor L1, it gradually decreases as shown in FIG.

Thereafter, when a period c (a period from time t3 to time t4 when the switching elements Q2 and Q3 are turned off) during a period c in which the direction of the current flowing through the inductor L1 is reversed due to the resonance action of the load circuit Z, FIG. 3), the current flowing in the path of the commercial power supply Vs, the rectifier circuit DB, the inductor L0, the switching element Q2, the rectifier circuit DB, and the commercial power supply Vs during the period b continues to flow, as shown in FIG. The current ID0 flowing through the inductor L0 increases with time. Further, the smoothing capacitor C0
-Switching element Q3-inductor L1-discharge lamp La
The charge of the smoothing capacitor C0 is discharged through the path of the capacitor C1-the switching element Q2-smoothing capacitor C0. This operation is performed at time t4 at switching elements Q2 and Q2.
It continues until Q3 turns off.

A period d until all the switching elements Q1 to Q3 turn on at time t5 until the switching elements Q2 and Q3 turn off at time t4 (all the switching elements Q1 to Q
4 (off period), the current flows in the direction of decreasing the electromagnetic energy as shown in FIGS. 3C and 3D by the holding current of the inductors L1 and L0. That is, as shown in FIG. 2D, a current flows through a path of commercial power supply Vs-rectifier circuit DB-inductor L0-diode D1-smoothing capacitor C0-rectifier circuit DB-commercial power supply Vs, and smoothing capacitor C0 is connected to rectifier circuit. The battery is charged with a voltage obtained by adding the voltage across the inductor L0 to the output voltage of DB. That is, an operation corresponding to the boost chopper circuit is performed by turning on / off the switching element Q2. Further, during this period d, a current flows through the path of the inductor L1-discharge lamp La and the capacitor C1-diode D1-smoothing capacitor C0-diode D4-inductor L1.

Thereafter, at time t5, the switching element Q
1, Q4 is turned on. In a period e from the time when the switching elements Q1 and Q4 are turned on to a time t6 when the current flowing through the inductor L1 is inverted, a current flows through the same path as the period d as shown in FIG. That is, the commercial power supply V
s-rectifier circuit DB-inductor L0-diode D1-
Smoothing capacitor C0-Rectifier circuit DB-Commercial power supply Vs path and inductor L1-Discharge lamp La and capacitor C1
-Diode D1-smoothing capacitor C0-diode D
4-Current flows through the path of the inductor L1.

After the switching elements Q1 and Q4 are turned on, when the polarity of the current flowing through the inductor L1 is inverted, a period f (a period from time t6 to time t7) until the current flowing through the inductor L0 stops. Is a commercial power supply Vs-rectifier circuit DB-inductor L0-switching element Q1-smoothing capacitor C0 as shown in FIG.
-A current flows continuously on a path of the rectifier circuit DB-the commercial power supply Vs, and a current flows on a path of the smoothing capacitor C0-the switching element Q1-the discharge lamp La and the capacitor C1-the inductor L1-the switching element Q4-the smoothing capacitor C0. . As shown in FIG. 3 (e), the smoothing capacitor C0 is charged in the first half of the period f, and the smoothing capacitor C0 is discharged in the second half.

Further, no current flows through inductor L0 at time t7 before switching elements Q1 and Q4 are turned off. As shown in FIG. 2 (g), current flows through the path of the smoothing capacitor C0-switching element Q1-discharge lamp La and capacitor C1-inductor L1-switching element Q4-smoothing capacitor C0. Thus, when the electromagnetic energy of the inductor L1 is released, a current flows again as shown in FIG. 2A, and the above-described operation is repeated.

As described above, in the configuration of the present embodiment, in the steady control mode, the switching element Q2 of the four switching elements Q1 to Q4 forming the inverter circuit INV is also used as a component of the boost chopper circuit. Therefore, the input current to the rectifier circuit DB can flow at a high frequency, and the high frequency blocking filter circuit F can suppress the high frequency from flowing into the commercial power supply Vs. Also, the switching elements Q1 to Q4
Since the input current from the commercial power supply Vs flows during most of the ON / OFF period of
The harmonic distortion of the input current can be reduced. Also,
By providing the above-described filter circuit F, the commercial power supply V
A current having a sinusoidal waveform proportional to the voltage Vin of s can be drawn, and the power factor can be improved.

Next, the operation in the input power control mode will be described. The operation when the on / off of the switching element Q2 is stopped in the input power control mode (the on / off of the switching element Q2 is thinned out in the input power control mode). Will be described with reference to FIG. 4 and FIG. In FIG. 4, as in FIG. 2, ON / OFF of each of the switching elements Q1 to Q4 is represented by whether the two end points are short-circuited or opened, and the state in which the current flows through the anti-parallel connected diodes D1 to D4 is the current. The diodes D1 to D4 through which the current flows are shown between the end points.

In the input power control mode, the switching elements Q1 and Q4 are turned on and off as shown in FIG. 5A, and the switching element Q3 is turned on and off as shown in FIG. 5C, so that the switching element Q2 is turned on and off intermittently. FIG. 5B shows a state where the switching element Q2 is stopped (maintained off). That is, FIGS. 4 and 5 illustrate the operation when the switching element Q2 is intermittently stopped. The operation when the switching element Q2 is not stopped is as described with reference to FIGS. 2 and 3. It is. FIG. 5A shows ON / OFF of the switching elements Q1 and Q4,
(B) ON / OFF of the switching element Q2, (c) ON / OFF of the switching element Q3, (d) an inductor L
1, (e) shows the current IL0 flowing through the inductor L0, (f) shows the current IC0 flowing through the smoothing capacitor C0, and each of the currents IL1, IL0, IC0 has a positive direction of the arrow in FIG. There is a direction.

As shown in FIGS. 5A and 5C, switching elements Q1 and Q4 and switching element Q3 are turned on and off alternately, and at time t1, switching elements Q1 and Q4 are turned on.
Is turned off, a period a (until all switching elements Q1
During a period during which Q4 is off, the inductor L1-diode D3-smoothing capacitor C0-diode D2-discharge lamp La and capacitor L1 as shown in FIG. 4 (a) by the holding current of inductor L1 (see FIG. 5 (d)). A current flows on the path of C1-inductor L1, and at the same time, a current also flows on the path of commercial power supply Vs-rectifier circuit DB-discharge lamp La and capacitor C1-inductor L1-diode D3-smoothing capacitor C0-rectifier circuit DB-commercial power supply Vs. . The operation in this period a is the same as in the steady control mode.

Next, immediately after the switching element Q3 is turned on, during a period b (a period from time t2 to time t3) during which the holding current of the inductor L1 flows as shown in FIG. FIG. 4 (b)
As shown in FIG.
A current flows through the path of the smoothing capacitor C0-diode D2-discharge lamp La and capacitor C1-inductor L1, and at the same time, commercial power supply Vs-rectifier circuit DB-inductor L
0-discharge lamp La and capacitor C1-inductor L1
-Flows on a path of switching element Q3-smoothing capacitor C0-rectifier circuit DB-commercial power supply Vs. Since the charging current IC0 of the smoothing capacitor C0 flows by the holding current of the inductor L1, the charging current IC0 gradually decreases as shown in FIG.

Thereafter, as shown in FIG. 5C, a period c during which the direction of the current flowing through the inductor L1 is reversed by the resonance action of the load circuit Z (a period from time t3 to time t4 when the switching element Q3 is turned off). , The current stops flowing through the inductor L0. During this period c, the inductor L1-discharge lamp La and the capacitor C1-diode D as shown in FIG.
A current flows through a path of 1-switching element Q3-inductor L1. The operation in which the switching element Q3 is not involved in the charging and discharging of the smoothing capacitor C0 even when the switching element Q3 is turned on in this way is called a zero clamp mode. In the zero clamp mode, as shown in FIG. 5C, a resonance current flows through the inductor L1, but the charging and discharging of the smoothing capacitor C0 is not performed.

Further, at time t4, switching element Q3
Is turned off, the period d (all the switching elements Q1 and Q4) is turned on until the time t5 when the switching elements Q1 and Q4 are turned on.
During the period when 1 to Q4 are off), a current flows in a direction to reduce the electromagnetic energy as shown in FIG. 5D by the holding current of the inductor L1. That is, as shown in FIG. 4D, the inductor L1-discharge lamp La and capacitor C1-diode D1-smoothing capacitor C0-diode D4-
A current flows through the path of the inductor L1.

Thereafter, at time t5, the switching element Q
1, Q4 is turned on. In a period e from the time when the switching elements Q1 and Q4 are turned on to a time t6 when the current flowing through the inductor L1 is inverted, as shown in FIG.
The current continues to flow on the same path as the period d shown in (d).
That is, as shown in FIG.
A current flows through the path of a and the capacitor C1-diode D1-smoothing capacitor C0-diode D4-inductor L1.

After the switching elements Q1 and Q4 are turned on, the polarity of the current flowing through the inductor L1 is reversed at time t6.
1, during a period f until the transistor Q4 is turned off, as shown in FIG. Electric current flows. When the electromagnetic energy of the inductor L1 is released in this way, a current flows again as shown in FIG. 4A, and the above operation is repeated.

As can be seen from the operation described above, by keeping the switching element Q2 off, the period during which the input current from the commercial power supply Vs flows can be reduced, and the input power can be controlled. The voltage Vdc across the terminals is prevented from being excessively boosted. Also,
As shown in FIG. 5C, the resonance current can be continuously supplied to the load circuit Z by turning on the switching element Q3 even when the switching element Q2 is turned off.

Therefore, in the power supply device of the present embodiment, the balance between the input power and the power consumption (output power) of the load circuit Z is maintained in order to suppress the excessive boosting of the voltage Vdc across the smoothing capacitor C0. In addition, in order to supply a sufficient preheating current to the filament during the preheating period of the discharge lamp La, the control circuit
4 is controlled.

In short, in the power supply device of the present embodiment, when the power consumption in the load circuit Z is small, the switching elements Q1, Q3, and Q4 are turned on and off intermittently while the switching element Q2 is turned on and off as in the steady-state control mode. By stopping (keeping off), excessive boosting of the smoothing capacitor C0 can be prevented.
It is possible to safely and stably operate a thin tube, a high-power discharge lamp, and the like, which require a high lamp voltage, without increasing the stress of the parts used.

That is, even if a ring-shaped fluorescent lamp having a rated lamp power of 97 W, a rated lamp current of 0.43 A, and a lamp voltage of 229 V is used as the discharge lamp La as a load, the structure shown in FIG. And it can be stably lit. In addition, as the discharge lamp La, a ring-shaped fluorescent lamp having the same shape, a rated lamp power of 68 W, a rated lamp current of 0.43 A, and a lamp voltage of 160 V can be used. Such a thin tube, a high-power discharge lamp with a high lamp voltage has an optical path length of 1400 mm to 2500 mm and a tube diameter of 18 mm.
２９29 mm.

In the circuit configuration shown in FIG. 1, the inductor L0 of the step-up chopper circuit is inserted between the positive terminal of the DC output terminal of the rectifier circuit DB and the connection point of the switching elements Q1 and Q2. As shown, the same effect can be obtained by inserting between the negative electrode of the DC output terminal of the rectifier circuit DB and the connection point of the switching elements Q2 and Q4. As shown in FIG. 7, both ends of the DC output terminal of the rectifier circuit DB are connected to inductors L.
A similar effect can be obtained even if the switching element Q1 is connected between both ends via a zero. Here, in the circuit configuration shown in FIG. 7, since the switching element Q1 functions as a switching element also serving as a chopper, the switching element Q1 is intermittently stopped in the input power control mode. Further, when a DC voltage may be superimposed on the load (discharge lamp) La, the circuit configuration as shown in FIG. 8 may be employed without the DC cut capacitor Cc.

(Embodiment 2) The basic configuration of the power supply device of this embodiment is substantially the same as that of Embodiment 1, and a control circuit (not shown) capable of arbitrarily controlling at least the on-duty of the switching element Q2 is used. In the input power control mode, the switching element Q
The feature is that the input power is adjusted by controlling the on-duty of the switching element Q2 instead of intermittently stopping the on / off of the switching element 2. Here, controlling the on-duty means changing the ratio of the on-period while keeping the frequency constant.

For example, if the ratio of the ON period in one cycle of the switching element Q2 is controlled to be small,
When the switching element Q2 is on, the commercial power V
The power taken from s is reduced, and the excessive boosting of the voltage Vdc across the smoothing capacitor C0 due to excess energy can be prevented. In the present embodiment, the discharge lamp La is used as a load as in the first embodiment, and the power consumption of the load circuit Z is small during the preheating period of the discharge lamp La, so that the ratio of the ON period of the switching element Q2 is reduced. By making the ON period relatively short, it is possible to prevent the voltage Vdc across the smoothing capacitor C0 from being excessively boosted.

Hereinafter, the operation in the input power control mode in the power supply device of the present embodiment will be described with reference to FIGS. 9 and 10. Note that the operation in the steady control mode is the same as that of the first embodiment, and the description is omitted.

FIG. 9 shows the configuration of FIG. 2 described in the first embodiment.
Similarly, the on / off state of each of the switching elements Q1 to Q4 is represented by whether the two end points are short-circuited or opened, and the state in which the current flows through the diodes D1 to D4 connected in anti-parallel is the state of the diodes D1 to D4 Is written between the end points.

In the input power control mode, FIGS.
The switching elements Q1 to Q4 are turned on and off as shown in FIG. 5A shows ON / OFF of the switching element Q1, FIG. 5B shows ON / OFF of the switching element Q2,
(C) ON / OFF of the switching element Q3, (d) ON / OFF of the switching element Q4, (e) an inductor L
1, the current IL1 flowing through the inductor L0, (f) represents the current IL0 flowing through the inductor L0, and (g) represents the current IC0 flowing through the smoothing capacitor C0.
The direction of the arrow in the middle is positive.

As shown in FIGS. 10A to 10D, switching elements Q1, Q4 and switching element Q3 are turned on and off alternately, and at time t1, switching elements Q1, Q4 are switched off.
4 is turned off, and at time t2, the switching element Q
During a period a (a period during which all the switching elements Q1 to Q4 are off) until Q2 is turned on, the inductor L1
9 (a), a current flows through the path of the inductor L1-diode D3-smoothing capacitor C0-diode D2-discharge lamp La and capacitor C1-inductor L1 as shown in FIG. Current also flows through the path of commercial power supply Vs-rectifier circuit DB-discharge lamp La and capacitor C1-inductor L1-diode D3-smoothing capacitor C0-rectifier circuit DB-commercial power supply Vs. The operation in this period a is the same as in the steady control mode.

Next, at time t2, switching element Q2
Immediately after Q3 is turned on, as shown in FIG. 10 (e), a period b (time t2
(Period until the time t3 when the holding current of the inductor L1 is inverted), as shown in FIG.
-Switching element Q3-Smoothing capacitor C0-Switching element Q2-Path of discharge lamp La and capacitor C1-Inductor L1, and commercial power supply Vs-Rectifier circuit DB-
Inductor L0-switching element Q2-rectifier circuit DB
-A current flows through the path of the commercial power supply Vs. During this period b, as the electromagnetic energy of the inductor L1 decreases, FIG.
0 (f), the current IL flowing through the inductor L0
0 increases. Also, the charging current I of the smoothing capacitor C0
Since C0 flows by the holding current of the inductor L1, it gradually decreases as shown in FIG.

Thereafter, during a period c (a period from time t3 to a time t4 when the switching element Q2 is turned off) until the switching element Q2 is turned off, as shown in FIG. -Rectifier circuit DB-Inductor L0-Switching element Q2-Rectifier circuit DB-
The current flowing on the path of the commercial power supply Vs continues to flow, and the current ID0 flowing through the inductor L0 increases with time as shown in FIG. Further, a smoothing capacitor C0-switching element Q3-inductor L1-discharge lamp La and capacitor C1-switching element Q2
-The charge of the smoothing capacitor C0 is released through the path of the smoothing capacitor C0. This operation is continued until the switching element Q2 is turned off at time t4.

During a period d from when the switching element Q2 is turned off at time t4 to when the switching element Q1 is turned on at time t5, the holding current of the inductor L1 causes
As shown in FIG. 9D, the inductor L1-discharge lamp La and capacitor C1-diode D1-switching element Q
3-Current flows through the path of the inductor L1 (zero clamp mode). In this zero clamp mode, FIG.
As shown in (e), a resonance current flows through the inductor L1.
In the period d, a current also flows through the path of the commercial power supply Vs, the rectifier circuit DB, the inductor L0, the diode D1, the smoothing capacitor C0, the rectifier circuit DB, and the commercial power supply Vs due to the holding current of the inductor L0.

FIG. 9E shows a period e (a period in which the switching elements Q2 and Q4 are off) from the time when the switching element Q1 is turned on at time t5 to the time when the switching element Q3 is turned off at time t6. In the period d, the inductor L1-discharge lamp La and capacitor C1-diode D1-switching element Q3-inductor L1
The current flowing in the path continues to flow. Also,
Due to the holding current of the inductor L0, a current continues to flow through the path of the commercial power supply Vs-rectifier circuit DB-inductor L0-diode D1-smoothing capacitor C0-rectifier circuit DB-commercial power supply Vs.

FIG. 10 (f) shows a period f (a period during which switching elements Q2, Q3, and Q4 are off) from when switching element Q3 is turned off at time t6 to when switching element Q4 is turned on at time t7. , The commercial power supply Vs-rectifier circuit DB-inductor L0-diode D1
-A current flows through the path of the smoothing capacitor C0-the rectifier circuit DB-the commercial power supply Vs, and the smoothing capacitor C0 is connected to the rectifier circuit DB.
Of the inductor L0 to the output voltage of the inductor L0. That is, an operation corresponding to the boost chopper circuit is performed by turning on / off the switching element Q2. Also, during this period f, the inductor L1-discharge lamp La
A current flows through a path of capacitor C1-diode D1-smoothing capacitor C0-diode D4-inductor L1.

Thereafter, at time t7, switching element Q4
During the period g from when the switch is turned on until the current flowing through the inductor L1 is inverted at time t8, a current flows through the same path as the period f as shown in FIG. 9 (g). That is, commercial power supply Vs-rectifier circuit DB-inductor L0-diode D
1-Smoothing capacitor C0-Rectifier circuit DB-Commercial power supply Vs
Current flows through the path of the inductor L1-discharge lamp La and capacitor C1-diode D1-smoothing capacitor C0-diode D4-inductor L1.

When the polarity of the current flowing through the inductor L1 is reversed, a period h (a period from time t8 to time t9) until the current flowing through the inductor L0 stops.
Is a commercial power supply Vs-rectifier circuit DB- as shown in FIG.
Current continues to flow through the path of inductor L0-switching element Q1-smoothing capacitor C0-rectifier circuit DB-commercial power supply Vs, and smoothing capacitor C0-switching element Q1-discharge lamp La and capacitor C1-inductor L1-switching element Q4. -Smoothing capacitor C
Current flows in the path of 0. As shown in FIG. 10 (g), in the first half of this period h, the smoothing capacitor C0 is charged,
In the latter half, the discharging of the smoothing capacitor C0 is performed.

Further, since no current flows through inductor L0 at time t9 before switching elements Q1 and Q4 are turned off, after that, during a period i until time t10 when switching elements Q1 and Q4 are turned off, FIG. As shown in FIG. 9 (i), a current flows through the path of the smoothing capacitor C0-switching element Q1-discharge lamp La and capacitor C1-inductor L1-switching element Q4-smoothing capacitor C0. Thus, when the electromagnetic energy of the inductor L1 is released, the current flows again as shown in FIG. 9A, and the above operation is repeated.

As can be seen from the operation described above, the on-duty of the switching element Q2 is reduced (the ratio of the on-period of the switching element Q2 is relatively smaller than the ratio of the on-period of the switching element Q2 in the steady control mode). Accordingly, the period during which the input current from the commercial power supply Vs flows is reduced, and the input power can be controlled. As a result, the voltage Vdc across the smoothing capacitor C0 can be obtained.
Is prevented from being excessively boosted. FIG.
As shown in (d) and (e), the switching element Q2
By turning on the switching element Q3 even in the state where is turned off, the resonance current can continue to flow through the load circuit Z (zero clamp mode).

In short, the present embodiment controls the on-duty of the switching element Q2 shared by the step-up chopper circuit, and turns on the switching element Q3 which is at a diagonal position to the switching element Q2 at least while the switching element Q2 is off. By turning on and off the switching elements Q3 and Q4 alternately (complementarily), it is possible to control the input power while flowing a resonance current to the load circuit Z.

Therefore, in the power supply device of the present embodiment, the balance between the input power and the power consumption (output power) of the load circuit Z is maintained in order to suppress the excessive boosting of the voltage Vdc across the smoothing capacitor C0. In addition, in order to supply a sufficient preheating current to the filament during the preheating period of the discharge lamp La, the control circuit
4 is controlled.

That is, since the on-duty of the switching element Q2 is reduced while the switching elements Q1 and Q2 are alternately turned on and off, and the switching elements Q3 and Q4 are turned on and off, excessive boosting of the smoothing capacitor C0 can be prevented. As in the first embodiment, it becomes possible to safely and stably operate a thin tube, a high-power discharge lamp, and the like that require a high lamp voltage without increasing the stress of the components used.

It is needless to say that the control circuit described in the present embodiment may be provided in the circuit configuration shown in FIGS. 7 to 9 described in the first embodiment. However, in the circuit configuration shown in FIG. 7, instead of controlling the on-duty of the switching element Q2, the on-duty of the switching element Q1 is controlled.

(Embodiment 3) The basic configuration of the power supply device of this embodiment is the same as the conventional configuration shown in FIG.
As shown in FIG. 1, a first series circuit in which a pair of switching elements Q1 and Q2 composed of MOSFETs are connected in series,
A pair of switching elements Q3 and Q
4 is connected in parallel with a second series circuit in which
A full-bridge type inverter circuit INV in which a load circuit Z is connected between a connection point between the two switching elements Q3 and Q4 in the first series circuit and a connection point between the two switching elements Q1 and Q2 in the second series circuit. Have. In FIG. 11, diodes D1 to D4 connected in anti-parallel to switching elements Q1 to Q4 are MOSFET Q1 respectively.
1 to 4 show body diodes. Also, the connection point between the switching elements Q1 and Q3 and the switching elements Q2 and Q4
Is connected to a smoothing capacitor C0.
Further, a series circuit in which two diodes D01 and D02 are connected in series in the forward direction is connected in parallel to the smoothing capacitor C0,
The other end of the inductor L0 having one end connected to the connection point between the two diodes D01 and D02 is connected to one output end of a filter circuit F connected to both ends of the commercial power supply Vs. The other output terminal of the filter circuit F is connected to a connection point between the switching elements Q1 and Q2. Diode D0
1 and D02 are connected to the polarities of a diode bridge together with the diodes D1 and D2.

The load circuit Z has a series circuit of a capacitor C1, an inductor L1, and a DC cut capacitor Cc. A discharge lamp La as a load is connected to the capacitor C1 in parallel, and is not shown. Is the capacitor C1
Are connected to the non-power supply side of the filament of the discharge lamp La.

The switching elements Q1 to Q4 are controlled by control signals S1 to S4 from a control circuit (not shown). Further, similarly to the above-described conventional configuration, a means (not shown) for detecting the voltage polarity of the commercial power supply Vs is provided.

The basic operation of this embodiment is substantially the same as that of the conventional configuration shown in FIG. 34. However, similarly to the first embodiment, control (input) is performed such that the control circuit intermittently stops the chopper switching element. Power control mode), the input power from the commercial power supply Vs is controlled, and the switching element at the diagonal position of the switching element also serving as a chopper is turned on and off, and a resonance current is supplied to the load circuit Z in the zero clamp mode. You can keep flowing. By the way, in the circuit configuration of the present embodiment, as described in the above conventional configuration, the switching element Q1 functions as a switching element also serving as a chopper in the positive half cycle of the commercial power supply Vs, and the switching element Q2 in the negative half cycle. Function as a chopper-switching element, a means for detecting the voltage polarity of the commercial power supply Vs described above (hereinafter referred to as voltage polarity detection means) is provided, and the control circuit operates based on the detection output of the voltage polarity detection means. The switching element to be stopped intermittently is determined.

Therefore, in the present embodiment, each of the two switching elements Q1, Q2, Q3, and Q4 is operated at a high frequency (a frequency sufficiently higher than the frequency of the commercial power supply Vs) without using the zero clamp mode. The switching elements Q1, Q4, Q which are turned on and off alternately and are at diagonal positions
The operation (operation in the steady control mode) when both Q2 and Q3 are controlled to be on at the same time is the same as the operation of the above-described conventional configuration.

That is, while the voltage Vin of the commercial power supply Vs is positive, the switching elements Q1 and Q4 are on while the commercial power supply Vs-inductor L0-diode D01-switching element Q1-commercial power supply Vs. A current flows, and a current also flows through the path of the smoothing capacitor C0-the switching element Q1-the load circuit Z-the switching element Q4-the smoothing capacitor C0. Inductor L
The current value passing through 0 is the voltage Vin (instantaneous value) of the commercial power supply Vs
Increase in proportion to When the switching elements Q1 and Q4 are turned off, the electromagnetic energy stored in the inductor L0 is equal to the inductor L0-diode D01-smoothing capacitor C0-diode D2-commercial power supply Vs-inductor L
0 is discharged and used for charging the smoothing capacitor C0. With this operation, the switching element Q1 of the inverter circuit INV is also used as a switching element of the boost chopper circuit.

Further, since switching elements Q2 and Q3 are turned on as switching elements Q1 and Q4 are turned off, when charging of smoothing capacitor C0 is completed, smoothing capacitor C0 is used as a power source for smoothing capacitor C0-switching element. Q3-Load circuit Z-Switching element Q
In FIG. 34, the load circuit Z is connected to the
The current flows to the left of.

On the other hand, during the negative half cycle of the commercial power supply Vs, during the ON period of the switching elements Q2 and Q3,
Commercial power supply Vs-switching element Q2-diode D0
Electromagnetic energy is accumulated in the inductor L0 by flowing a current through the path of (2-inductor L0-commercial power supply Vs). This electromagnetic energy is applied to the switching elements Q2, Q2
3 turns off, inductor L0-commercial power supply Vs-diode D1-smoothing capacitor C0-diode D02
-Smoothing capacitor C is discharged through the path of inductor L0.
Used to charge 0. Also, in the negative half cycle, an AC voltage is applied to the load circuit Z using the smoothing capacitor C0 as a power supply. In short, in the negative half cycle, the switching element Q2 of the inverter circuit INV is also used as the switching element of the boost chopper circuit.

Therefore, in the present embodiment, the control circuit detects the commercial power Vs based on the detection output of the voltage polarity detection means.
Although the switching element Q1 is intermittently stopped in the positive half cycle, the switching element Q4 is alternately turned on and off with the switching element Q3, and the switching element Q2 is intermittently stopped in the negative half cycle of the commercial power supply Vs. Even if the switching element Q3
By performing control so as to turn on and off alternately with the control circuit 4 (operating the switching elements Q1 to Q4 in the input power control mode), the input power is controlled while flowing the resonance current to the load circuit Z as in the first embodiment. Can be.

Incidentally, similarly to the second embodiment, the control circuit is configured to control the on-duty of the switching element also serving as a chopper, thereby controlling the input power from the commercial power supply Vs and the switching circuit serving also as the chopper. Even if the switching element at a diagonal position to the element is turned on and off so that the resonance current continues to flow through the load circuit Z in the zero clamp mode, the input power can be controlled while the resonance current flows through the load circuit Z.

(Embodiment 4) The circuit configuration and basic operation of the power supply device of the present embodiment are the same as those of Embodiment 1, and the voltage Vdc across the smoothing capacitor C0 after the power is turned on.
Is characterized by the control of the switching element Q2 by the control circuit in a period until the voltage reaches a set value (hereinafter, referred to as a Vdc set value) and becomes stable. Here, the power supply device according to the present embodiment includes a voltage Vd across the smoothing capacitor C0.
a voltage detection circuit (not shown) for detecting c.
The control circuit controls the number of pulses of the control signal S2 of the switching element Q2 in a certain period so that the voltage detected by the voltage detection circuit becomes equal to the set value of Vdc.

Although the smoothing capacitor C0 is used which has a relatively large element tolerance with a margin for the Vdc set value, the Vdc set value is made as large as possible to be close to the element tolerance. It is conceivable to use a capacitor having a relatively small element resistance as the smoothing capacitor C0 by setting the value. Here, when the power is turned on in the power supply device of the first embodiment, the voltage Vdc across the smoothing capacitor C0 increases with the passage of time. However, when the Vdc set value is set to a value close to the element withstand capability, the voltage Vdc increases. The time delay of the detection circuit (Δ
Due to t), there is a possibility that the voltage Vdc across the smoothing capacitor C0 exceeds the set value of Vdc and further exceeds the withstand voltage of the element, as indicated by a broken line G in FIG.

In the present embodiment, in order to solve this kind of inconvenience, the control circuit controls the switching element Q2 during the period in which the voltage Vdc across the smoothing capacitor C0 increases with time, such as immediately after power-on. Signal S
It is characterized in that the number of pulses in the fixed period 2 is changed as shown by a solid line A in FIG. 12 (that is, the rate at which the switching element Q2 is turned off intermittently is changed). That is, the control circuit keeps the number of pulses of the control signal S2 substantially constant until the voltage detected by the voltage detection circuit reaches a predetermined value smaller than the Vdc set value, and controls the control signal as the detected voltage approaches the Vdc set value from the predetermined value. Control is performed such that the number of pulses of the signal S2 is reduced (the ON state of the switching element Q2 is thinned out). By performing such control, the voltage Vd across the smoothing capacitor C0 is obtained.
c shows the solid line A ′ in FIG.
And the rising speed near the Vdc set value becomes smaller than the rising speed immediately after the power is turned on. Therefore, even if there is a time delay (Δt) of the voltage detection circuit, the smoothing capacitor C0 can be used. It is possible to prevent the terminal voltage Vdc from reaching the element withstand voltage.

Thus, in the power supply device of the present embodiment, as in the first embodiment, not only can the input power be controlled while the resonance current flows through the load circuit Z, but also the voltage Vdc across the smoothing capacitor C0 can be controlled. Can be quickly raised and do not exceed the element tolerance, and the operation is stable and the reliability can be increased.

The switching element Q by the control circuit
12, the control is performed such that the number of pulses of the control signal S2 of the switching element Q2 in a certain period gradually decreases as the voltage detected by the voltage detection circuit increases, as shown by a dashed line B in FIG. Is also good. By performing such control, the smoothing capacitor C0
Of the voltage Vdc of the smoothing capacitor C0 becomes slower with the rising curve as shown by the one-dot chain line B ′ in FIG.
The voltage V across the smoothing capacitor C0 near the set value of Vdc
Since the rising speed of dc can be made smaller than the rising speed immediately after the power is turned on, it is possible to prevent the voltage Vdc across the smoothing capacitor C0 from reaching the element withstand even if there is a time delay (Δt) of the voltage detection circuit. Become.

The voltage Vd across the smoothing capacitor C0
By increasing the number of pulses of the control signal S2 of the switching element Q2 during the period when c is smaller than the predetermined value as compared with the first embodiment, the voltage Vd across the smoothing capacitor C0 is increased.
Control may be performed to further increase the rising speed of c. Also, during the period when the voltage across the smoothing capacitor C0 is low, only the switching element Q2 is turned on and off and the other switching elements Q1, Q3, and Q4 are kept off, so that the smoothing capacitor C0 continues to be charged without being discharged. Can be shortened until the voltage Vdc reaches the set value.

(Embodiment 5) The circuit configuration and the basic operation of the power supply device of the present embodiment are substantially the same as those of the first embodiment.
The voltage Vdc across the smoothing capacitor C0 is equal to a set value (hereinafter, referred to as “Vdc”).
The control circuit controls the switching element Q2 until the switching element Q2 reaches the Vdc setting value and stabilizes. Here, the power supply device of the present embodiment includes a voltage detection circuit (not shown) for detecting the voltage Vdc across the smoothing capacitor C0, and the control circuit changes the voltage detected by the voltage detection circuit to the Vdc set value. The number of pulses and the on-duty of the control signal S2 of the switching element Q2 in a certain period are controlled so as to be equal.

As the smoothing capacitor C0, a capacitor having a relatively large element tolerance with respect to the Vdc set value is used, but the Vdc set value is increased as much as possible to reduce the element tolerance. By setting the values close to each other, it is conceivable to use a smoothing capacitor C0 having a relatively small element resistance. Here, when the power is turned on in the power supply device of the first embodiment, the voltage Vdc across the smoothing capacitor C0 gradually increases with time, but when the Vdc set value is set to a value close to the element withstand capability, Due to the time delay (Δt) of the voltage detection circuit, there is a possibility that the voltage Vdc across the smoothing capacitor C0 exceeds the set value of Vdc and further exceeds the element resistance as shown by a broken line G in FIG.

In the present embodiment, in order to solve this kind of problem, during a period in which the voltage Vdc across the smoothing capacitor C0 increases with time, such as immediately after power-on, the control circuit operates the control signal of the switching element Q2. S2
Are changed as shown by the solid line A in FIG. 13 and the on-duty of the control signal S2 is changed as shown by the solid line A ″ in FIG. The voltage detected by the voltage detection circuit is V
Until the predetermined value smaller than the dc set value is reached, the number of pulses and the on-duty of the control signal S2 are made substantially constant. As the detected voltage approaches the Vdc set value from the predetermined value, the number of pulses and the on-duty of the control signal S2 respectively Is controlled so as to reduce. By performing such control, the voltage Vdc across the smoothing capacitor C0 increases in a rising curve as shown by a solid line A 'in FIG. 13, and the rising speed near the Vdc set value is smaller than immediately after the power is turned on. Therefore, even if there is a time delay (Δt) of the voltage detection circuit, the voltage Vd across the smoothing capacitor C0
It is possible to prevent c from reaching the element withstand capability.

Thus, in the power supply device of the present embodiment, as in the first embodiment, not only the input power can be controlled while the resonance current flows through the load circuit Z, but also the voltage Vdc across the smoothing capacitor C0. Can be quickly raised and do not exceed the element tolerance, and the operation is stable and the reliability can be increased.

The switching element Q by the control circuit
2 is performed by controlling the voltage Vd across the smoothing capacitor C0.
The number of pulses of the control signal S2 of the switching element Q2 during the period when c is smaller than the predetermined value is increased as compared with the case of the first embodiment to increase the rising speed of Vdc.
As shown by a two-dot chain line B ″, even if control is performed such that the on-duty of the control signal S2 of the switching element Q2 is rapidly reduced when the voltage detected by the voltage detection circuit approaches a set value of Vdc to some extent. By performing such control, the voltage Vdc across the smoothing capacitor C0 increases in a rising curve as shown by a two-dot chain line B in Fig. 13, and the rate of rise of the voltage Vdc across the smoothing capacitor C0 increases. The rising speed of the voltage Vdc across the smoothing capacitor C0 in the vicinity of the set value of Vdc can be made smaller than immediately after the power is turned on. Therefore, even if there is a time delay (Δt) of the voltage detection circuit, the smoothing capacitor C0
Can be prevented from reaching the element withstand voltage. When such control is performed, control may be performed such that the number of pulses of the control signal S2 in a certain period is also rapidly reduced when the voltage detected by the voltage detection circuit approaches a set value of Vdc to some extent.

(Embodiment 6) The circuit configuration and the basic operation of the power supply device of this embodiment are the same as those of Embodiment 1, and the voltage Vdc across the smoothing capacitor C0 after the power is turned on.
Is characterized by the control of the switching element Q2 by the control circuit until the voltage reaches the Vdc set value and becomes stable. Here, the power supply device of the present embodiment includes a voltage detection circuit (not shown) for detecting the voltage Vdc across the smoothing capacitor C0, and the control circuit changes the voltage detected by the voltage detection circuit to the Vdc set value. The number of pulses, on-duty, and the like of the control signal S2 of the switching element Q2 in a certain period are controlled so as to be equal.

As the smoothing capacitor C0, a capacitor having a relatively large element tolerance with respect to the Vdc set value is used, but the Vdc set value is increased as much as possible to reduce the element tolerance. By setting the values close to each other, it is conceivable to use a smoothing capacitor C0 having a relatively small element resistance. Here, when the power is turned on in the power supply device of the first embodiment, the voltage Vdc across the smoothing capacitor C0 increases with the passage of time. If the predetermined value Vpa (detection point PA) for determining the timing for changing the state of S2 is set equal to the Vdc set value, the time delay (Δt) of the voltage detection circuit causes a broken line G in FIG. As shown, the voltage Vd across the smoothing capacitor C0
There is a possibility that c may exceed the set value of Vdc and further exceed the element resistance.

In the present embodiment, in order to solve this kind of problem, when the voltage Vdc across the smoothing capacitor C0 rises, the control circuit determines the timing for changing the state of the control signal S2. Value Vpb
(Detection point PB) is set lower than the Vdc set value. That is, when the voltage detected by the voltage detection circuit reaches a predetermined value Vpb smaller than the Vdc set value, the control circuit suppresses the increase in the voltage Vdc across the smoothing capacitor C0 by controlling the number of pulses of the control signal S2, on-duty, and the like. Control to be performed. By performing such control, the voltage Vdc across the smoothing capacitor C0 increases in a rising curve shown by a solid line A 'in FIG. 14, and the smoothing capacitor C0 near the Vdc set value is increased.
Since the rise of the voltage Vdc at both ends of 0 is suppressed, it is possible to prevent the voltage Vdc across the smoothing capacitor C0 from reaching the element withstand capability even if the voltage detection circuit has a time delay (Δt).

In the power supply device of this embodiment, as in the first embodiment, the input power can be controlled while the resonance current flows through the load circuit Z, and the voltage Vdc across the smoothing capacitor C0 can be controlled. Can be quickly raised and do not exceed the element withstand capability, and the operation is stable and the reliability can be increased.

(Embodiment 7) The circuit configuration and basic operation of the power supply device of the present embodiment are the same as those of Embodiment 1, and the voltage Vdc across the smoothing capacitor C0 after the power is turned on.
Is characterized by the control of the switching element Q2 by the control circuit until the voltage reaches the Vdc set value. Here, the power supply device of the present embodiment includes a voltage detection circuit (not shown) for detecting the voltage Vdc across the smoothing capacitor C0, and the control circuit determines that the voltage detected by the voltage detection circuit is V
The number of pulses of the control signal S2 of the switching element Q2 (the number of times the switching element Q2 is turned on in a certain period), the on-duty, and the like are controlled to be equal to the dc set value.

As the smoothing capacitor C0, a capacitor having a relatively large element tolerance with respect to the Vdc set value is used, but the Vdc set value is increased as much as possible to reduce the element tolerance. By setting the values close to each other, it is conceivable to use a smoothing capacitor C0 having a relatively small element resistance. Here, when the power is turned on in the power supply device of the first embodiment, the voltage Vdc across the smoothing capacitor C0 increases with the passage of time. However, when the Vdc set value is set to a value close to the withstand element, the control signal If the predetermined value Vpa (detection point P _A ) for determining the timing for changing the state of S2 is set equal to the set value of Vdc, the time lag (Δt) of the voltage detection circuit causes a broken line G in FIG. The voltage Vd across the smoothing capacitor C0 as shown by
There is a possibility that c may exceed the set value of Vdc and further exceed the element resistance.

In the present embodiment, in order to solve this kind of problem, when the voltage Vdc across the smoothing capacitor C0 rises, the control circuit determines a predetermined timing for changing the state of the control signal S2. Value Vpb
The feature is that (detection point P _B ) is set lower than the Vdc set value. In the present embodiment, Vdc
Increases the number of pulses of the control signal S2 of the switching element Q2 or the on-duty until the voltage reaches the predetermined value Vpb, thereby increasing the voltage Vd across the smoothing capacitor C0.
The rising speed of dc is increased. That is, in the present embodiment, the time required for the voltage Vdc across the smoothing capacitor C0 to reach the predetermined value Vpb is shorter than in the sixth embodiment, and the control circuit determines that the voltage detected by the voltage detection circuit is V
When the predetermined value Vpb, which is smaller than the dc set value, is reached, control is performed such that the number of pulses of the control signal S2, on-duty, and the like are suppressed from increasing the voltage Vdc across the smoothing capacitor C0. By performing such control, the voltage Vdc across the smoothing capacitor C0 increases in a rising curve shown by a solid line A ′ in FIG. 15, and the increase in the voltage Vdc across the smoothing capacitor C0 near the set value of Vdc. Since the voltage is suppressed, it is possible to prevent the voltage Vdc across the smoothing capacitor C0 from reaching the element withstand even if there is a time delay of the voltage detection circuit.

In the power supply device according to the present embodiment, as in the first embodiment, the input power can be controlled while the resonance current flows through the load circuit, and the voltage Vdc across the smoothing capacitor C can be controlled. It is possible to quickly raise the temperature and not to exceed the element withstand capability, thereby achieving stable operation and high reliability.

In the third embodiment, the same control may be performed by providing the voltage detection circuit.

(Eighth Embodiment) The basic configuration of a power supply device according to the present embodiment is substantially the same as that of the first embodiment, and as shown in FIG. Is added, and the control circuit 10 drives the drive circuits 121 to ₁ to output pulse signals from the control pulse generation circuit 11 as control signals S1 to S4.
12 ₄ is provided with a stop circuit 13 for stopping the output of the pulse signal to the driving circuit 12 ₂ from the control pulse generation circuit 11. Here, stop circuit 13, or it is stopped or passed through a pulse signal to the driving circuit 12 ₂ in response to the detected voltage level of the voltage detection circuit 21. Here, the control circuit 10, for turning on and off the switching element Q1~Q4 by applying a pulse signal from the control pulse generating circuit 11 as the control signal S1~S4 through driving circuits 12 ₁ to 12 _4. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

Also in this embodiment, the discharge lamp La is used as the load, and the capacitor C1 is connected to the non-power supply side of the filament.
Is connected.

In the boost chopper circuit described in the first embodiment, circuit constants and the like are set so as to take in optimum power when the discharge lamp La is turned on.
Since the power consumption during the preheating period a is smaller than the power taken in by the boost chopper circuit, if the switching element Q2 is operated in the same manner as when the discharge lamp La is turned on, the input power becomes larger than the output power. In addition, the voltage Vdc across the smoothing capacitor C0 may be excessively boosted, and the stress applied to the element may be increased, and the element may be destroyed.

The power supply device of the present embodiment solves this kind of problem. The voltage detection circuit 21 detects the peak value of the potential of the positive electrode at the DC output terminal of the rectifier circuit DB,
The stop circuit 13 switches the switching element Q according to the detection level.
2 is intermittently stopped to stop the step-up chopper operation, and the voltage Vdc across the smoothing capacitor C0.
Suppress the rise. That is, since the switching element Q2 is controlled while performing the feedforward by detecting the magnitude of the peak value of the potential Vi of the positive electrode at the DC output terminal of the rectifier circuit DB, the smoothing is performed more accurately and quickly than when the feedforward control is not performed. The voltage Vdc across the capacitor C0 is V
DC setting value can be approached. Note that the inverter circuit INV can supply a resonance current to the discharge lamp La as a load by the operation (input power control mode) described in the first embodiment even if the switching element Q2 is intermittently stopped.

Here, if the set value of Vdc is set to a value that can supply sufficient power to the discharge lamp La within a range that does not apply excessive stress to the element, the smoothing capacitor C0 can be quickly set after the power is turned on. The voltage Vdc between both ends can be raised to the Vdc set value, the filament of the discharge lamp La can be easily preheated in a short period of time, and the discharge lamp La has a thin tube as shown in FIG. Even if a lamp is used, a preheating current required for the preheating period can be secured.

In short, the power supply device of the present embodiment is designed to maintain the balance between the input power and the output of the load circuit Z in order to suppress the rise of the voltage Vdc across the capacitor C0, and to prevent the discharge lamp La from moving forward. The control circuit controls each of the switching elements Q1 to Q4 so that a sufficient preheating current is supplied to the filament during the preheating period.

As the discharge lamp La of this embodiment, a ring-shaped fluorescent lamp having a rated lamp power of 97 W, a rated lamp current of 0.43 A and a lamp voltage of 229 V, a lamp of the same shape having a rated lamp power of 68 W, and a rated lamp current of May be used, and a ring fluorescent lamp having a lamp voltage of 160 V may be used. Note that these annular fluorescent lamps are thin tube, high-power discharge lamps having a high lamp voltage, and having an optical path length of 1400 mm or more.
Some have a diameter of 2500 mm and a pipe diameter of 18 mm to 29 mm.

In the third embodiment, the same control may be performed by providing the voltage detection circuit 21.

(Embodiment 9) The basic configuration of a power supply device according to the present embodiment is substantially the same as that of Embodiment 1, and as shown in FIG. 17, a voltage detector for detecting the effective value of the voltage Vdc across the smoothing capacitor C0. A control circuit that adds a circuit 22 and a comparator circuit 23 that compares a detection output of the voltage detection circuit 22 with a set value set by the setting circuit 24 and generates a predetermined output when the detected output exceeds the set value; 10 is characterized in that by adding a stop circuit 13 for stopping the pulse signal from the control pulse generating circuit 11 receives a predetermined output of the comparator circuit 23 to the drive circuit 12 _2. Here, the control circuit 10 outputs the pulse signals from the control pulse generation circuit 11 to the drive circuits 121 to ₁ .
For turning on and off the switching element Q1~Q4 by providing a control signal S1~S4 through 12 _4.
The stop circuit 13 has been inserted between the drive circuit 12 ₂ for driving a control pulse generating circuit 11 and the switching element Q2. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

Also in this embodiment, a discharge lamp La having two filaments is used as a load, and a capacitor C1 is connected to the non-power supply side of the filament.

In the boost chopper circuit described in the first embodiment, circuit constants and the like are set so as to take in optimum power when the discharge lamp La is turned on.
Since the power consumption during the preheating period a is smaller than the power taken in by the step-up chopper circuit, if the switching element Q2 is operated in the same manner as when the discharge lamp La is turned on, the input power becomes larger than the output power. As a result, the voltage Vdc across the smoothing capacitor C0 increases, and the stress applied to the element increases, possibly leading to destruction of the element.

The power supply device according to the present embodiment solves this kind of problem. When the voltage detected by the voltage detection circuit 22 exceeds the set value set by the setting circuit 24, the operation of the switching element Q2 is intermittently performed. To stop the step-up chopper operation and
0 is suppressed from increasing. That is, since the switching element Q2 is controlled while detecting and feeding back the voltage Vdc across the smoothing capacitor C0, the voltage Vdc across the smoothing capacitor C0 approaches the set value more accurately and quickly than when no feedback control is performed. Can be. Note that the inverter circuit INV can supply a resonance current to the discharge lamp La as a load by the operation described in the first embodiment (zero clamp mode) even when the switching element Q2 is intermittently stopped.

Here, if the above set value is set to a value that can supply sufficient power to the discharge lamp La within a range that does not apply excessive stress to the element, the smoothing capacitor C0 can be quickly turned on after the power is turned on. The voltage Vdc between both ends can be raised to a set value, and it is easy to preheat the filament of the discharge lamp La in a short period of time. As the discharge lamp La, a thin tube as shown in FIG. , A sufficient preheating current can be secured.

In short, the power supply device of the present embodiment maintains the balance between the input power and the output of the load circuit Z in order to suppress the rise of the voltage Vdc across the smoothing capacitor C0, and also controls the discharge lamp La The control circuit controls the switching elements Q1 to Q4 so that a sufficient preheating current is supplied to the filament during the preheating period.

As the discharge lamp La of this embodiment, an annular fluorescent lamp having a rated lamp power of 97 W, a rated lamp current of 0.43 A and a lamp voltage of 229 V, a lamp of the same shape having a rated lamp power of 68 W, and a rated lamp current of May be used, and a ring fluorescent lamp having a lamp voltage of 160 V may be used. As a thin tube, a high-power discharge lamp with a high lamp voltage, the optical path length is 1400 mm to 2500 mm, and the tube diameter is 18 mm to
There is a thing of 29 mm.

The voltage detection circuit 22 in the present embodiment detects the effective value of the voltage Vdc across the smoothing capacitor C0.
c may be detected, or the commercial power supply V
The peak value of the voltage Vdc across the smoothing capacitor C0 may be detected with a time constant of about several cycles of s.

In the third embodiment, the voltage detection circuit 2
2 and the like may be provided to perform the same control.

(Embodiment 10) The basic configuration of a power supply device of this embodiment is substantially the same as that of Embodiment 9 and has a circuit configuration as shown in FIG. The feature is that the values VH and VL (where VH> VL) are set, and the comparison circuit 22 has hysteresis. The voltage Vdc across the smoothing capacitor C0 is controlled so as to fall within a range between the two set values VH and VL. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Also in this embodiment, the discharge lamp L having two filaments is used as a load.
a and a capacitor C1 on the non-power supply side of the filament.
Is connected.

In the power supply device of the present embodiment, the effective value of the voltage Vdc across the smoothing capacitor C0 is detected by the voltage detection circuit 22, and as shown in FIG. 19, when the detected voltage exceeds the set value VH, the switching element By stopping the operation of Q2, the chopper operation is stopped to suppress an increase in the voltage Vdc across the smoothing capacitor C0. Thereafter, when the voltage Vdc across the smoothing capacitor C0 becomes equal to or less than the set value VL, the switching element Q2 is operated. The voltage Vdc across the smoothing capacitor C0 is increased. As described above, in the present embodiment, by providing the comparison circuit 22 with hysteresis, it is possible to add hysteresis to the voltage at which the operation of the switching element Q2 switches, so that malfunction due to noise or the like near the set value can be prevented. Can be.

As in the ninth embodiment, if the set value is set to a value that can provide sufficient power to the discharge lamp La within a range that does not apply excessive stress to the element, a short time after the power is turned on, And the voltage Vdc across the smoothing capacitor C0
Can be increased to a set value, it is easy to preheat the filament of the discharge lamp in a short period, and even if a thin tube as shown in FIG. 36 and a high-efficiency annular fluorescent lamp are used as the discharge lamp, The pre-heating current can be secured.

The voltage detection circuit 2 according to the present embodiment
2, the effective value of the voltage Vdc across the smoothing capacitor C0 is detected. However, the average value of the voltage Vdc across the smoothing capacitor C0 may be detected, or a time constant of about several cycles of the commercial power supply Vs may be used. Voltage V across the smoothing capacitor C0
The peak value of dc may be detected. In the third embodiment, the same control may be performed by providing the voltage detection circuit 22 and the like.

(Embodiment 11) The basic configuration of the power supply device of the present embodiment is substantially the same as that of Embodiment 1, and as shown in FIG. 20, a voltage detection device for detecting the peak value of the voltage Vdc across the smoothing capacitor C0. The circuit 22 is added and the control circuit 10
Is characterized in that an output control circuit 13 'for controlling a pulse signal from the control pulse generation circuit 11 according to the detection level of the voltage detection circuit 22 is provided. Here, the control circuit 10
Is the output a pulse signal generated by the control pulse generating circuit 11 as the control signal S1~S4 through driving circuits 12 ₁ to 12 ₄ switching elements Q1~Q4 intended to on-off control, the output control circuit 13, the control It is provided between the pulse generation circuit 11 and the drive circuit 12 _2. In addition,
The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In this embodiment, a discharge lamp La having two filaments is used as a load, and a capacitor C1 is connected to the non-power supply side of the filament.

The boost chopper circuit described in the first embodiment is set so as to take in the optimum power when the discharge lamp La is turned on. However, the power consumption in the preheating period of the discharge lamp La is taken in by the chopper circuit. The switching element Q2 is connected to the discharge lamp L
If the operation is performed in the same manner as at the time of lighting a, the input power becomes larger than the output power, so that the voltage Vdc across the smoothing capacitor C0 increases, the stress applied to the element increases, and the element may be destroyed.

The power supply device of the present embodiment solves this kind of problem, and detects the voltage detected by the voltage detection circuit 22 (the peak value of the voltage Vdc across the smoothing capacitor C0).
By setting the period during which the output control circuit 13 'stops the switching element Q2 according to the magnitude of the voltage, the excessive boosting of the voltage Vdc across the smoothing capacitor C0 is suppressed.
That is, since the switching element Q2 is controlled while detecting and feeding back the voltage Vdc across the smoothing capacitor C0, the voltage Vdc across the smoothing capacitor C0 approaches the set value more accurately and quickly than when no feedback control is performed. Can be.

The voltage Vd across the smoothing capacitor C0
By regularly stopping the switching element Q2 in synchronization with the cycle of the peak value of c, the same effect as in the tenth embodiment can be obtained. Further, the same control may be performed by adding the voltage detection circuit 22 in the configuration of the third embodiment.

(Embodiment 12) The power supply device of this embodiment
The basic configuration is substantially the same as that of the first embodiment, and is shown in FIG.
As described above, the control circuit 10 includes the resistor R15 and the capacitor C1.
And a timer circuit 15 formed of a series circuit with
The switching element Q2 is turned on by the elapsed time from the on-time.
The feature is that it is configured to control the duty.
is there. Here, the control circuit 10 includes the control pulse generation circuit 1
The pulse signal generated in step 1 ₁~ 12_FourThrough
Switching elements Q1 to Q4 as control signals S1 to S4.
And a control pulse generation circuit.
11 and drive circuit 12_Two, 12_ThreeControl pulse generation times between
For controlling the on-duty of the pulse signal from the road 11
A duty ratio control circuit 16 is inserted. Also control
The circuit 10 includes a resistor R15 and a capacitor of the timer circuit 15.
An output voltage Va based on a potential Va1 at a connection point with C15.
2 is provided with a mode switching circuit 17 that switches in three stages.
The duty ratio control circuit 16 includes a mode switching circuit 17
Of the pulse signal based on the output voltage Va2 of
To control the security Here, mode off
The conversion circuit 17 has a cathode connected to the resistor R15 and the capacitor C1.
5 and a pair of zener diodes ZD connected to the connection point
1, ZD2, and the zener diode ZD2
The Zener voltage VZ2 is the Zener of the Zener diode ZD1.
It is set higher than the voltage VZ1. Vc in FIG.
c indicates a power supply voltage, and the power supply voltage Vcc is
The output may be obtained by smoothing the output or using an external power supply.
It may be a constant DC voltage. The implementation
The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
Omitted.

The operation of the power supply according to the present embodiment will be described below with reference to FIG.

FIG. 22 shows the waveforms of the respective parts after the power is turned on in FIG. 22, (a) shows the voltage Va1 waveform, (b) shows the on / off state of the switching element Sw1, (c) shows on / off of the switching element Sw2, and (d) Shows the waveform of the voltage Va2, (e) shows the on-duty of the control signal S2 of the switching element Q2, and (f) shows the waveform of the voltage Vdc across the smoothing capacitor C0.

Before turning on the commercial power supply, the switching element Sw
1 and Sw2 are both off, and when the commercial power supply Vs is turned on at time t0, Va1 as shown in FIG.
Increases with time, and when the voltage Va1 reaches the Zener voltage VZ1 of the Zener diode ZD1 at time t1,
Switching elements Sw1 as shown in FIG. 22 (b) is turned on and conducts the Zener diode ZD1, the voltage Va2 is lowered from Va2 ₃ Va2 ₁ to (Va2 _3> Va2 _1).
Then, the duty ratio control circuit 16 controls the control signal S2.
Is the on-duty OD immediately after power-on
3 to OD1 (OD3> OD1).

Thereafter, the voltage Va1 further increases as shown in FIG.
When the voltage Va1 reaches the Zener voltage VZ2 of the Zener diode ZD2 at time t2, the Zener diode ZD2 becomes conductive and the switching element Sw2 turns on as shown in FIG. 22B, and the voltage Va2 rises as shown in FIG. Va2
_It rises from ₁ to Va2 ₂ (Va2 ₁ <Va2 ₂ <Va2 ₃ ). Then, the duty ratio control circuit 16 changes the on-duty of the control signal S2 from OD1 to OD2 (OD1 <O
D2 <OD3).

By the above operation, the smoothing capacitor C
0, the terminal voltage Vdc changes as shown in FIG. 22 (f). When attention is paid to the on-duty of the switching element Q2, the voltage Vdc across the smoothing capacitor C0 immediately after the power is turned on.
In order to increase dc quickly, a relatively large value (OD
Although the input power is increased by setting to 3), the discharge lamp L
Since the power consumption during the preceding preheating period and the starting period is smaller than during lighting, the on-duty is set to a relatively small value (O
D1), the power consumption is large during lighting, so the on-duty is larger than during pre-heating and at startup (OD2)
Is set to

Thus, in the present embodiment, the same effects as in the above embodiment can be obtained with a simple control circuit 10 using the timer circuit 15 without performing feedback control or feedforward control. Note that the same effect can be obtained by changing the frequency of switching (turning on) the switching element Q2 instead of changing the on-duty of the switching element Q2.

(Thirteenth Embodiment) The basic configuration of a power supply device according to the present embodiment is substantially the same as that of the first embodiment, and as shown in FIG. 23, a voltage detector for detecting the effective value of the voltage Vdc across the smoothing capacitor C0. The circuit 22 is added and the control circuit 10
The control signal S according to the detection level of the voltage detection circuit 22.
The second embodiment is characterized in that a duty ratio control circuit 16 for controlling the on-duty of S3 is provided. Here, the control circuit 1
0 is a switching element Q1~Q4 a pulse signal generated by the control pulse generating circuit 11 as the control signal S1~S4 through driving circuits 12 ₁ to 12 ₄ in which on-off control, duty ratio control circuit 16, a pulse generator It is provided between the circuit 11 and the drive circuits 12 ₂ and 12 ₃ . Note that the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In this embodiment, a discharge lamp La having two filaments is used as a load, and a capacitor C1 is connected to the non-power supply side of the filament.

Incidentally, the step-up chopper circuit is a discharge lamp La
Is set so as to take in the optimum power when the lamp is turned on, but the power consumption during the preheating period of the discharge lamp La is smaller than the power taken in by the boost chopper circuit. If the operation is performed in the same manner as during lighting, the input power becomes larger than the output power, so that the voltage Vdc across the smoothing capacitor C0 increases,
In some cases, the stress applied to the device is increased and the device may be destroyed.

The power supply device of the present embodiment solves this kind of problem. When the detection voltage (effective value of the voltage Vdc across the smoothing capacitor C0) of the voltage detection circuit 22 increases, the control signal S2 is turned on. The duty is reduced to suppress an increase in the voltage Vdc across the smoothing capacitor C0, and when the detection voltage decreases, the on-duty is increased to increase Vdc. That is, the voltage Vdc across the smoothing capacitor C0 is detected and fed back and the amount of power drawn in the boost chopper circuit is controlled, so that the voltage Vdc across the smoothing capacitor C0 is set more accurately and quickly than when no feedback control is performed. Value can be approached. Here, the inverter circuit INV can flow the resonance current to the discharge lamp La by the same operation as that of the first embodiment regardless of the operation and the stop of the switching element Q2.

If the set value is set to a value that can provide sufficient power to the load within a range that does not apply an excessive stress to the element, the voltage Vdc across the smoothing capacitor C0 can be reduced in a short time after the power is turned on. The discharge lamp La can be raised to the set value, and the filament of the discharge lamp La can be easily preheated in a short period of time. Even when a thin tube and a high-efficiency annular fluorescent lamp as shown in FIG. Thus, a preheating current can be secured.

The voltage detection circuit 2 according to the present embodiment
2, the effective value of the voltage Vdc across the smoothing capacitor C0 is detected. However, an average value of the voltage Vdc across the smoothing capacitor C0 may be detected, or a time constant of about several cycles of the commercial power supply Vs may be used. Voltage V across the smoothing capacitor C0
The peak value of dc may be detected. In the third embodiment, the same control may be performed by providing the voltage detection circuit 22 and the like.

(Embodiment 14) As shown in FIG. 24, the power supply device of this embodiment has a circuit configuration obtained by combining Embodiment 9 and Embodiment 13, and includes a smoothing capacitor C0.
To control the on-duty of the control signal of the switching element Q2, and stop the operation of the switching element Q2 when the voltage detected by the voltage detection circuit 22 reaches the set value set by the setting circuit 24. Thus, the excessive increase in the voltage Vdc across the smoothing capacitor C0 is sharply suppressed, and the voltage Vdc across the smoothing capacitor C0 can be increased to the set value with higher accuracy in a shorter period of time. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In particular, when a discharge lamp La having a hot cathode is used as a load, the output voltage is stabilized by controlling the on-duty of the switching element Q2 including the rated lighting to stabilize the voltage Vdc across the smoothing capacitor C0. Further, at the time of preheating, which is a light load, the voltage Vdc across the smoothing capacitor C0 sharply rises, so that the switching element Q2
Is added to control the voltage Vdc across the smoothing capacitor C0 more accurately.

As described above, in the present embodiment, there is an effect that the input power can be controlled quickly and accurately with respect to a load such as the discharge lamp La in which the load fluctuates greatly. Further, it becomes possible to preheat and start a thin tube and a high-efficiency ring-shaped fluorescent lamp as shown in FIG. 36 immediately after turning on the power. In the third embodiment, the voltage detection circuit 22
May be provided to perform the same control.

(Embodiment 15) The basic configuration of a power supply device of the present embodiment is substantially the same as that of Embodiment 1, and as shown in FIG. 25, a discharge lamp L having two filaments as a load as shown in FIG.
a is used. Here, the discharge lamp La has a capacitor C1 connected to the non-power supply end of the filament. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In this embodiment, the switching elements Q1 to Q1
It is characterized in that a control circuit (not shown) for controlling ON / OFF of Q4 controls the switching frequency (drive frequency) of switching elements Q1 to Q4.

Hereinafter, the operation of the power supply device of the present embodiment will be described with reference to FIG.

FIG. 26 shows the operation waveform of each part.
FIG. 26A shows a no-load secondary voltage of the discharge lamp La, and FIG.
Represents the filament current, (c) represents the voltage Vdc across the smoothing capacitor C0, and (d) represents the switching frequency (drive frequency).

When the driving frequency is constant at fpre from the start of the preheating as shown by the broken line B in FIG. 26 (d), the voltage Vdc across the smoothing capacitor C0 as shown by the broken line B in FIG. 26 (c). Takes a relatively long time to reach the Vdc set value at the time of preceding preheating. Therefore, FIG.
As shown by the broken line B in FIG. 6 (b), the rising of the filament current also becomes in line with the rising of the voltage Vdc across the smoothing capacitor C0, and the average during a certain period before the voltage Vdc across the smoothing capacitor C0 stabilizes. The filament preheating current is the voltage Vdc across the smoothing capacitor C0.
Becomes smaller than the filament preheating current after the stabilization. If an attempt is made to increase the filament preheating current, the no-load secondary voltage of the discharge lamp La also increases, and the stress applied to the discharge lamp La increases.
There is a problem that the life of a is shortened.

On the other hand, in the present embodiment, the control circuit sets the drive frequency at the start of the preheating as shown by a solid line A in FIG.
The characteristic is that the drive frequency approaches fpre as the voltage Vdc across the smoothing capacitor C0 approaches the set value.

By performing such control, the filament current during the period when the voltage Vdc across the smoothing capacitor C0 rises to the set value is increased while suppressing the rise of the no-load secondary voltage, and the voltage across the smoothing capacitor C0 is increased. It is possible to increase the average filament preheating current for a certain period before Vdc is stabilized at the Vdc set value. In addition, when the driving frequency decreases, the power drawn by the boost chopper circuit also increases. Therefore, as shown by the solid line A in FIG. 26C, the rising speed of the voltage Vdc across the smoothing capacitor C0 increases, and the voltage across the smoothing capacitor C0 increases. The time required for Vdc to reach the set value is also reduced.

The driving frequency is changed from fpre ′ to fpr
In order to change the driving frequency to e, feedback control for changing the driving frequency by detecting the voltage Vdc across the smoothing capacitor C0 may be performed. Furthermore, it may be combined with the circuits of the ninth, thirteenth, and fourteenth embodiments.

As described above, in this embodiment, it is possible to increase the preheating current of the filament while suppressing the stress on the discharge lamp La. Note that, in the third embodiment, the same control may be performed by providing a voltage detection circuit for detecting the voltage Vdc across the smoothing capacitor C0.

(Embodiment 16) The basic configuration of a power supply device according to this embodiment is substantially the same as that of Embodiment 1, and the load circuit Z has a transformer T as shown in FIG.
The difference is that a capacitor C1 is connected between both ends of the secondary winding, and a discharge lamp La as a load is connected between both ends of the secondary winding of the transformer T. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In this embodiment, the same effect can be obtained by performing the same control as in the first and second embodiments.

In the first and second embodiments,
Since both ends of the discharge lamp La are electrically connected to the negative electrode of the smoothing capacitor C0 only through the switching element Q2 or the switching element Q4, they are in a state of floating at a high frequency. On the other hand, in this embodiment, since the discharge lamp La is connected to both ends of the secondary winding of the transformer T, even if one end of the discharge lamp La is electrically connected to the negative electrode of the smoothing capacitor C0, Since power can be applied, radiation noise from the discharge lamp La can be suppressed, and safety can be easily ensured.

(Embodiment 17) The basic configuration of a power supply device of this embodiment is substantially the same as that of Embodiment 16, and a discharge lamp La having a filament as a load as shown in FIG. It is characterized in that a capacitor C1 is connected therebetween (constituting a so-called C preheating circuit). Note that the same components as those of the sixteenth embodiment are denoted by the same reference numerals, and description thereof is omitted.

In the power supply device of the present embodiment, the magnitude of the filament current of the discharge lamp La is determined by the voltage between both ends of the discharge lamp La and the impedance of the capacitor C1, and the driving frequency of the inverter circuit INV is relatively increased during the preheating. Thus, a large filament current is obtained in a short time.

As shown in FIG. 29, a preheating circuit 31 composed of a capacitor C31 and a preheating winding on the secondary side of the transformer T may be connected to each filament of the discharge lamp La. The apparatus can optimally preheat the filament irrespective of the voltage across the discharge lamp La. Here, it goes without saying that the capacitor C1 may be provided on the primary side of the transformer T.

In this embodiment, if a step-up transformer is used as the transformer T, for example, a ring-shaped fluorescent lamp having a high lamp voltage as shown in FIG. 36 can be easily started and stably lit, and the filament preheating condition must be satisfied. Will also be easier.

The technical concept of the present embodiment may be applied to the third embodiment.

[0181]

According to the first aspect of the present invention, there is provided a smoothing capacitor,
A first series circuit in which a pair of switching elements having diodes connected between both ends of the smoothing capacitor and connected in antiparallel to each other are connected in series; and a diode connected between both ends of the smoothing capacitor and connected in antiparallel to each other And a second series circuit in which a pair of switching elements having a series connection are connected between the connection points of the pair of switching elements constituting the first and second series circuits including the LC resonance circuit and the load, respectively. A load circuit;
A pulsating power supply obtained by rectifying commercial power is connected between both ends of at least one switching element of the series circuit via an inductor, and has a period in which switching elements at diagonal positions are simultaneously turned on, and the first and second switching elements have a period. A steady-state control mode in which a pair of switching elements constituting a series circuit are alternately turned on and off, and a pulsating power supply in a first series circuit in which a pair of switching elements constituting a second series circuit are alternately turned on and off. An intermittent stop of the on / off of the switching element connected between both ends, and an input power control mode having a period in which the other switching element of the first series circuit is turned on simultaneously with the switching element at the diagonal position. Therefore, a switching element having a pulsating power supply connected between both ends constitutes a part of the step-up chopper circuit together with the inductor. In addition, by operating in the input power control mode even if the power required for the load changes, the on / off of the switching element connected between both ends of the pulsating power supply can be intermittently reduced. By stopping the operation, the period during which the input current from the commercial power supply flows can be reduced to prevent the voltage across the smoothing capacitor from being excessively boosted, and the switching element connected between both ends of the pulsating power supply is located at a diagonal position. Since the resonance current can be continuously supplied to the load circuit by turning on and off the switching element, the power supply to the load circuit can be controlled while controlling the input power, and the voltage across the smoothing capacitor is adjusted to an appropriate value. And the required power can be stably supplied to the load.

According to a second aspect of the present invention, in the first aspect of the present invention, a pulsating power source obtained by rectifying a commercial power source is connected between both ends of one switching element of the first series circuit via an inductor. There is an effect that one switching element forms a part of the boost chopper circuit and has a function of improving input current distortion.

According to a third aspect of the present invention, in the first aspect of the present invention, a pulsating power source obtained by rectifying a commercial power source is connected between both ends of each switching element of the first series circuit via an inductor. In the mode, since the switching elements in which the commercial power supply is stopped during the positive half cycle and the negative half cycle are different, each switching element of the first series circuit forms a part of the step-up chopper circuit and the input current. There is an effect that a function of improving distortion can be provided.

The invention according to claim 4 is a first series circuit in which a smoothing capacitor and a pair of switching elements each having a diode connected between both ends of the smoothing capacitor and connected in antiparallel with each other are connected in series; A second series circuit in which a pair of switching elements having diodes connected between both ends of the capacitor and connected in antiparallel to each other are connected in series; and a first and a second series circuit each including an LC resonance circuit and a load. A load circuit connected between the connection points of each pair of switching elements, and a pulsating power supply obtained by rectifying a commercial power supply between both ends of at least one switching element of the first series circuit is connected via an inductor; Each pair of switches constituting the first and second series circuits has a period during which the switching elements at diagonal positions are simultaneously turned on. And a pair of switching elements forming a first and a second series circuit having a period in which a switching element at a diagonal position is simultaneously turned on and a pair of switching elements constituting a first and second series circuit being alternated. And an input power control mode in which the pulsating power supply of the first series circuit controls the on-duty of the switching element connected between both ends of the first series circuit. A part of the boost chopper circuit can be configured together with the inductor to reduce the input current distortion.Also, even if the power required for the load changes, it operates in the input power control mode to connect between both ends of the pulsating power supply. The on-duty of the switched switching element is reduced to reduce the period during which the input current from the commercial power supply flows The voltage across the smoothing capacitor can be prevented from being excessively boosted, and the switching element at the diagonal position of the switching element connected between both ends of the pulsating power supply is turned on and off, so that the resonance current continues to flow through the load circuit. Therefore, the power supplied to the load circuit can be controlled while controlling the input power, the voltage across the smoothing capacitor can be set to an appropriate value, and the required power can be supplied to the load stably. There is an effect that can be.

A fifth aspect of the present invention, according to the first to fourth aspects, further comprises a control circuit for turning on and off each switching element, wherein the control circuit pulsates according to the magnitude of the voltage value across the smoothing capacitor. The voltage across the smoothing capacitor is controlled to a substantially set value by changing the number of times that the switching element to which the power supply is connected is turned on within a predetermined period, so that the voltage across the smoothing capacitor is controlled to an appropriate value with good controllability. There is an effect that it can be controlled.

According to a sixth aspect of the present invention, in the first to fourth aspects of the present invention, a control circuit for turning on / off each switching element is provided, and the control circuit pulsates according to the magnitude of the voltage value across the smoothing capacitor. Since the voltage across the smoothing capacitor is controlled to a substantially set value by changing the on-duty of the switching element connected to the power supply, the voltage across the smoothing capacitor can be controlled to an appropriate value with good controllability. There is.

A seventh aspect of the present invention, according to the first to fourth aspects, further comprises a control circuit for turning on and off each switching element, wherein the control circuit pulsates in accordance with the magnitude of the voltage value across the smoothing capacitor. Since the voltage across the smoothing capacitor is controlled to a substantially set value by changing the operating frequency of the switching element to which the power supply is connected, the voltage across the smoothing capacitor can be controlled to an appropriate value with good controllability. This has the effect.

An eighth aspect of the present invention, according to the first to fourth aspects of the present invention, further comprises a control circuit for turning on and off each switching element, wherein the control circuit comprises an effective value, an instantaneous value, and a peak value of the pulsating power supply. The voltage across the smoothing capacitor is controlled to a substantially set value by controlling the operation of the switching element on the side to which the pulsating power supply is connected in accordance with one size, so that the voltage across the smoothing capacitor is set to an appropriate value. There is an effect that control can be performed with good controllability.

In a ninth aspect of the present invention, in the first to fifth aspects, a control circuit for turning on / off each switching element is provided, and the control circuit controls the operation of the switching element to which the pulsating power supply is connected. When the voltage across the smoothing capacitor is controlled to a substantially set value by switching, when the voltage across the smoothing capacitor reaches a first predetermined value, the side to which the pulsating power supply is connected so as to suppress the rise in the voltage across the smoothing capacitor. When the voltage across the smoothing capacitor reaches a second predetermined value, the operation of the switching element to which the pulsating power supply is connected is switched so that the voltage across the smoothing capacitor rises. Hysteresis can be added to the voltage for switching the operation of the connected switching element, or malfunction due to noise can be prevented. Can not, there is an effect that can be controlled with good controllability of the voltage across the smoothing capacitor to the appropriate value.

A tenth aspect of the present invention is the invention according to the first to fifth aspects, further comprising a control circuit for turning on and off each switching element, wherein the control circuit makes a voltage value across the smoothing capacitor reach a predetermined value after power-on. During this period, the voltage across the smoothing capacitor is substantially set to a set value by changing the number of times the switching element connected to the pulsating power supply is turned on within a certain period according to the magnitude of the voltage value across the smoothing capacitor. , The voltage between both ends of the smoothing capacitor can be increased to a desired voltage value in a relatively short time, and there is an effect that stable and highly reliable operation can be performed.

An eleventh aspect of the present invention is the invention according to the first to fifth aspects, further comprising a control circuit for turning on and off each switching element, wherein the control circuit is connected to a pulsating power supply in accordance with the elapsed time from the power-on. Since the voltage at both ends of the smoothing capacitor is controlled to a substantially set value by controlling the operation of the switching element on the side that has been set, the voltage across the smoothing capacitor can be raised to a desired voltage value in a relatively short time, There is an effect that stable and highly reliable operation becomes possible.

In a twelfth aspect of the present invention, in accordance with the first to fifth aspects, a control circuit for turning on / off each switching element is provided, and the control circuit causes the voltage value across the smoothing capacitor to reach a predetermined value after power-on. During this period, the number of on-duties and the on-duty of the switching element to which the pulsating power supply is connected are changed according to the magnitude of the voltage value across the smoothing capacitor to change the voltage across the smoothing capacitor. Since the voltage is controlled to a substantially set value, the voltage between both ends of the smoothing capacitor can be increased to a desired voltage value in a relatively short time, and there is an effect that stable and highly reliable operation can be performed.

According to a thirteenth aspect of the present invention, in the first to twelfth aspects, since the load is a discharge lamp, an appropriate voltage across the smoothing capacitor is obtained irrespective of the state of the discharge lamp during a preheating period or after lighting. Thus, the electric power required for the discharge lamp can be stably supplied.

According to a fourteenth aspect, in the thirteenth aspect, the discharge lamp has a rated lamp power of about 97 W, a rated lamp current of about 0.43 A, and a lamp voltage of about 229 V.
Since the ring-shaped fluorescent lamp described above is used, it is possible to stably supply necessary power to such a high-output fluorescent lamp and to stably turn on the high-output fluorescent lamp.

According to a fifteenth aspect, in the thirteenth aspect, the discharge lamp has a rated lamp power of about 68 W, a rated lamp current of about 0.43 A, and a lamp voltage of about 160 V.
Since the ring-shaped fluorescent lamp described above is used, it is possible to stably supply necessary power to such a high-output fluorescent lamp and to stably turn on the high-output fluorescent lamp.

According to a sixteenth aspect, in the thirteenth aspect, the discharge lamp has an optical path length of about 1400 to 2500.
mm and a tube diameter of about 18 to 29 mm, it is possible to stably supply electric power required for such a discharge lamp having a long optical path length, and to stably light the lamp.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment.

FIG. 2 is an operation explanatory view of the above.

FIG. 3 is an operation explanatory diagram of the above.

FIG. 4 is an operation explanatory diagram of the above.

FIG. 5 is an operation explanatory view of the above.

FIG. 6 is a circuit diagram of another configuration example of the embodiment.

FIG. 7 is a circuit diagram of another configuration example of the embodiment.

FIG. 8 is a circuit diagram of another configuration example of the embodiment.

FIG. 9 is an operation explanatory view of the above.

FIG. 10 is an operation explanatory view of the above.

FIG. 11 is a circuit diagram showing a third embodiment.

FIG. 12 is an operation explanatory diagram of the fourth embodiment.

FIG. 13 is an operation explanatory diagram of the fifth embodiment.

FIG. 14 is an operation explanatory diagram of the sixth embodiment.

FIG. 15 is an operation explanatory diagram of the seventh embodiment.

FIG. 16 is a circuit diagram showing an eighth embodiment.

FIG. 17 is a circuit diagram showing a ninth embodiment;

FIG. 18 is a circuit diagram showing a tenth embodiment.

FIG. 19 is a diagram illustrating the operation of the above.

FIG. 20 is a circuit diagram showing an eleventh embodiment.

FIG. 21 is a circuit diagram showing a twelfth embodiment.

FIG. 22 is an explanatory diagram of the above operation.

FIG. 23 is a circuit diagram showing a thirteenth embodiment.

FIG. 24 is a circuit diagram showing a fourteenth embodiment.

FIG. 25 is a circuit diagram showing a fifteenth embodiment;

FIG. 26 is an explanatory diagram of the above operation.

FIG. 27 is a circuit diagram showing a sixteenth embodiment.

FIG. 28 is a circuit diagram showing a seventeenth embodiment.

FIG. 29 is a circuit diagram showing another configuration example of the above.

FIG. 30 is a circuit diagram showing a conventional example.

FIG. 31 is a circuit diagram of a control circuit of the above.

FIG. 32 is an explanatory diagram of the above operation.

FIG. 33 is an explanatory diagram of the operation of the above.

FIG. 34 is a circuit diagram showing another conventional example.

FIG. 35 is an explanatory diagram of the operation of the above.

36A is an external view of a discharge lamp, and FIG. 36B is an explanatory view of a main part of FIG.

[Explanation of symbols]

 La Discharge lamp L0 Inductor L1 Inductor C0 Smoothing capacitor C1 Capacitor INV Inverter circuit Z Load circuit Q1 to Q4 Switching element D1 to D4 Diode Vs Commercial power supply DB Rectifier circuit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masahiro Naroo 1048, Kazuma, Kadoma, Osaka Prefecture Inside Matsushita Electric Works, Ltd. (72) Inventor Kazuo Hori 1048, Kazuma, Kazuma, Kadoma, Osaka Prefecture Matsushita Electric Works, Ltd. (72) Inventor Masato Onishi 1048 Odaka, Kazuma, Osaka Prefecture F-term in Matsushita Electric Works Co., Ltd. CC07 DB01 DC05

Claims (16)

[Claims] 1. A first series circuit in which a smoothing capacitor, a pair of switching elements having diodes connected between both ends of the smoothing capacitor and connected in antiparallel to each other are connected in series, and between both ends of the smoothing capacitor. A second series circuit in which a pair of switching elements having diodes connected in anti-parallel to each other are connected in series, and a pair of switching elements respectively forming the first and second series circuits each including an LC resonance circuit and a load. A load circuit connected between the connection points of the elements, a pulsating power supply obtained by rectifying commercial power supply across both ends of at least one switching element of the first series circuit is connected via an inductor, and is located at a diagonal position. Each pair of switching elements that have a period in which the switching elements are simultaneously turned on and that constitute the first and second series circuits are connected to each other. The steady control mode in which the switching elements are alternately turned on and off, and the switching elements in the first series circuit in which the pair of switching elements are alternately turned on and off and the pulsating power supply of the first series circuit is connected between both ends are intermittently turned on and off. And an input power control mode having a period during which the other switching element of the first series circuit is simultaneously turned on at the same time as the switching element at the diagonal position. 2. The power supply device according to claim 1, wherein a pulsating power supply obtained by rectifying a commercial power supply is connected between both ends of one switching element of the first series circuit via an inductor. 3. A pulsating power supply obtained by rectifying a commercial power supply is connected between both ends of each switching element of the first series circuit via an inductor. In the input power control mode, the commercial power supply has a positive half cycle and a negative power cycle. 2. The power supply device according to claim 1, wherein a switching element that is intermittently stopped differs between the half cycle period and the half cycle period. 4. A first series circuit in which a smoothing capacitor, a pair of switching elements having diodes connected between both ends of the smoothing capacitor and connected in antiparallel to each other are connected in series, and between both ends of the smoothing capacitor. A second series circuit in which a pair of switching elements having diodes connected in anti-parallel to each other are connected in series, and a pair of switching elements respectively forming the first and second series circuits each including an LC resonance circuit and a load. A load circuit connected between the connection points of the elements, a pulsating power supply obtained by rectifying commercial power supply across both ends of at least one switching element of the first series circuit is connected via an inductor, and is located at a diagonal position. Each pair of switching elements that have a period in which the switching elements are simultaneously turned on and that constitute the first and second series circuits are connected to each other. A steady control mode in which the switching elements are alternately turned on and off, and a period in which the switching elements at the diagonal positions are simultaneously turned on, and each pair of switching elements constituting the first and second series circuits are alternately turned on and off; A power supply device comprising: an input power control mode for controlling an on-duty of a switching element connected between both ends of the pulsating power supply in the first series circuit. 5. A control circuit for turning on / off each switching element, wherein the control circuit turns on a switching element to which a pulsating power supply is connected within a predetermined period according to a magnitude of a voltage value across the smoothing capacitor. The power supply device according to any one of claims 1 to 4, wherein the voltage between both ends of the smoothing capacitor is controlled to a substantially set value by changing the number of times the power supply is performed. 6. A control circuit for turning on / off each switching element, wherein the control circuit changes an on-duty of a switching element to which a pulsating power supply is connected according to a magnitude of a voltage value across the smoothing capacitor. 5. The power supply device according to claim 1, wherein the voltage across the smoothing capacitor is controlled to a substantially set value. 7. A control circuit for turning on / off each switching element, wherein the control circuit changes the operating frequency of the switching element to which the pulsating power supply is connected according to the magnitude of the voltage value across the smoothing capacitor. 5. The power supply device according to claim 1, wherein the voltage across the smoothing capacitor is controlled to a substantially set value. 8. A control circuit for turning on / off each switching element, wherein the control circuit is connected to the pulsating power supply in accordance with one of an effective value, an instantaneous value, and a peak value of the pulsating power supply. 5. The power supply device according to claim 1, wherein the voltage across the smoothing capacitor is controlled to a substantially set value by controlling the operation of the switching element. 9. A control circuit for turning on and off each switching element, wherein the control circuit switches the operation of the switching element to which the pulsating power supply is connected to control the voltage across the smoothing capacitor to a substantially set value. When the voltage across the smoothing capacitor reaches a first predetermined value, the operation of the switching element to which the pulsating power supply is connected is switched so as to suppress the rise of the voltage across the smoothing capacitor, and the voltage across the smoothing capacitor becomes the second voltage. The power supply device according to any one of claims 1 to 4, wherein the operation of the switching element to which the pulsating power supply is connected is switched so that the voltage between both ends increases when the predetermined value is reached. 10. A control circuit for turning on / off each switching element, wherein the control circuit adjusts the magnitude of the voltage value across the smoothing capacitor until the voltage value across the smoothing capacitor reaches a predetermined value after the power is turned on. 6. The voltage between both ends of a smoothing capacitor is controlled to a substantially set value by changing the number of times of ON of a switching element to which a pulsating power supply is connected in a predetermined period accordingly. The power supply according to any one of the above. 11. A smoothing capacitor comprising a control circuit for turning on and off each switching element, wherein the control circuit controls an operation of a switching element to which a pulsating power supply is connected in accordance with an elapsed time from power-on. The power supply device according to any one of claims 1 to 5, wherein the voltage between both ends is controlled to a substantially set value. 12. A control circuit for turning on / off each switching element, wherein the control circuit adjusts the magnitude of the voltage value across the smoothing capacitor until the voltage value across the smoothing capacitor reaches a predetermined value after the power is turned on. The voltage between both ends of the smoothing capacitor is controlled to a substantially set value by changing the number of times and the on-duty of the switching element on the side to which the pulsating power supply is connected in a predetermined period accordingly. Item 6. The power supply device according to any one of Items 5. 13. The power supply device according to claim 1, wherein the load is a discharge lamp. 14. The discharge lamp has a rated lamp power of about 9
7. A ring-type fluorescent lamp having a lamp power of 7 W, a rated lamp current of approximately 0.43 A, and a lamp voltage of approximately 229 V.
3. The power supply device according to 3. 15. The discharge lamp has a rated lamp power of about 6
2. A ring-type fluorescent lamp of 8 W, a rated lamp current of approximately 0.43 A, and a lamp voltage of approximately 160 V.
3. The power supply device according to 3. 16. The discharge lamp has an optical path length of about 1400 to about 1400.
14. The power supply according to claim 13, wherein the diameter is 2500 mm and the tube diameter is approximately 18 to 29 mm.