JP2002125380A - Power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply which can readily restart an inverter circuit, when abnormal state is released. SOLUTION: An inverter circuit INV is provided with a preheating circuit PH for controlling preheating of a gas discharge lamp, included in a load circuit Z, and emissionless-state detecting circuit EL, which makes the inverter circuit INV oscillate intermittently through the preheat circuit PH, when the gas discharge lamp turns into emissionless state. In the inverter circuit INV, a half- bridge type is made a basic constitution, one of switching elements Q1, Q2 is served as partial smoothing, and automatic operation is constituted by using a feedback transformer DT1. A discharge resister Rd is connected between both ends of a smoothing capacitor C0 for partial smoothing, and makes electric charges of the smoothing capacitor C0 discharged, when oscillation of the inverter circuit INV is stopped due to the operation of the emissionless-state detecting circuit EL.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for converting power from an AC power supply such as a commercial power supply and supplying high-frequency power to a load circuit.

[0002]

2. Description of the Related Art Generally, this type of power supply device rectifies an AC power supply Vin with a rectifier DB as shown in FIG.
The output of the rectifier DB is converted into high frequency power by the inverter circuit INV and supplied to the load circuit Z. The illustrated inverter circuit INV employs a so-called composite partial smoothing system in which a so-called half-bridge type series inverter is used as a basic configuration and the inverter circuit INV has a harmonic reduction function, and constitutes the inverter circuit INV. Feedback transformer D for switching elements Q1 and Q2
When the output of the inverter circuit INV is fed back via T1, both switching elements Q1 and Q2 are configured to perform a self-excited operation. Further, as the load circuit Z, an output transformer LT1 including a leakage transformer
A capacitor C4 connected to the secondary side of the output transformer LT1 so as to form a resonance circuit together with the leakage inductance of the output transformer LT1, and a hot cathode type discharge lamp FL such as a fluorescent lamp connected in parallel to the capacitor C4. Including. Specifically, the secondary winding n2 of the output transformer LT1
Is connected to one end of each filament of the discharge lamp FL, and a capacitor C4 is connected between the other ends of the filaments.
Will be connected.

In order to employ the load circuit Z having such a configuration, a preheating circuit PH is required as another control circuit for preheating the discharge lamp FL, and the end state of the discharge lamp FL (so-called Emiless state) is required. ) Is also provided with an Emiless detection circuit EL as an abnormality detection circuit. Here, the end-of-life state means that the electron-emitting substance (emitter) evaporates at one of the two hot cathodes (filaments) provided in the discharge lamp FL and the discharge lamp F
L means a state in which a half-wave is turned on.

The inverter circuit INV includes a series circuit of a pair of switching elements Q1 and Q2 connected between the DC output terminals of a rectifier DB, a primary winding of a feedback transformer DT1, a load circuit Z, and a DC cut capacitor. A series circuit with C1 is connected in parallel to one switching element Q1, and one switching element Q2 is used together with a partial smoothing circuit as a switching element constituting a step-down chopper type active filter. Here, the one switching element Q1 is connected to the high potential side of the output terminal of the rectifier DB with respect to the other switching element Q2. The element Q2 is called a low-side switching element Q2 as needed. A MOSFET is used for each of the switching elements Q1 and Q2, so that even when the switching elements Q1 and Q2 are turned off, a current in a direction opposite to that when the switching elements Q1 and Q2 are turned on can flow through the body diodes. In other words, the switching element is equivalent to a configuration in which a diode is connected in anti-parallel to the collector / emitter of the transistor. Here, anti-parallel is a polarity that allows a current in a direction opposite to the forward current between the collector and the emitter when the transistor is turned on to flow through the diode, and connects the diode in parallel with the collector and emitter of the transistor. Means that.

The feedback transformer DT1 has two secondary windings, and resistors R1 and R2 are connected to each of the secondary windings. A series circuit of each secondary winding and each of the resistors R1 and R2 has a The switching elements Q1 and Q2 are connected in parallel to the gate and source. However, the polarities of the respective secondary windings of the feedback transformer DT1 with respect to the transistors Q1 and Q2 are opposite to each other, so that when one switching element Q1 is on, the other transistor Q2 is off.
A starting circuit is connected to the gate of the low-side switching element Q2. In the starting circuit, a series circuit of the resistor R3 and the capacitor C3 is connected between the DC output terminals of the rectifier DB, and a connection point between the resistor R3 and the capacitor C3 is connected to the gate of the switching element Q2 via the trigger element TD1. In addition, a connection point between the resistor R3 and the capacitor C3 is connected to the drain of the switching element Q2 via the diode D4. Here, the polarity of the diode D4 is the same as that of the low-side switching element Q2.
Is turned on so that the charge of the capacitor C3 can be discharged when the switch is turned on.

In the partial smoothing circuit, a series circuit of a smoothing capacitor C0, an inductor L1 as an inductance element, and a diode D3 is connected between the DC output terminals of the rectifier DB. The connection point between the feedback transformer DT1 and the load circuit Z is connected through the connection. Therefore, a series circuit including the smoothing capacitor C0, the inductor L1, the diode D1, the primary winding of the feedback transformer DT1, and the low-side switching element Q2 is connected between the DC output terminals of the rectifier DB. The polarity of diode D1 is such that when switching element Q2 is on, rectifier DB-smoothing capacitor C0-inductor L1-diode D1-primary winding of feedback transformer DT1-switching element Q2-rectifier DB
The polarity is such that the charging current can flow through the smoothing capacitor C0 through the path of. The polarity of the diode D3 is such that when the switching element Q2 is turned on, the smoothing capacitor C0, the capacitor C1, the load circuit Z, the primary winding of the feedback transformer DT1, the switching element Q2, the diode D3, and the inductor L1.
The polarity is such that the discharge current of the smoothing capacitor C0 can flow through the path of the smoothing capacitor C0. Switching element Q2
Whether the smoothing capacitor C0 is charged or discharged at the time of turning on depends on the magnitude relationship between the output voltage of the rectifier DB and the voltage across the smoothing capacitor C0. Smoothing capacitor C0, inductor L1, and diode D3, which form a partial smoothing circuit
Is connected in parallel with a power factor improving capacitor C2.

As described above, since the inverter circuit INV shown in the figure performs a self-excited operation, no control is necessary during a steady operation (ie, a period during which the discharge lamp FL is stably lit). During the period, power is supplied to the load circuit Z so that the discharge lamp FL is not turned on, and at the end of life, the output of the inverter circuit INV is reduced (including operation stop) so that stress is not applied to the inverter circuit INV. An operation different from that in the normal operation is required. Therefore, a preheating circuit PH for controlling the preheating period and an Emiless detection circuit EL for controlling at the end of life are provided, and the on / off of the low-side switching element Q2 can be controlled by the preheating circuit PH and the Emiless detection circuit EL. is there.
In short, the inverter circuit INV performs a self-excited operation, but adopts a configuration in which another control is performed on the low-side switching element Q2 only when an operation different from that in the normal operation is required.

The preheating circuit PH includes a pnp transistor Q6 whose emitter is connected to the gate of the switching element Q2 and whose collector is connected to the source. The base and collector of the transistor Q6 are connected to the npn transistor Q5. Collector and emitter are connected in parallel. A series circuit of a resistor R10, a diode D10, a capacitor Ct1 having a relatively large capacitance and a capacitor Cp1 having a relatively small capacitance is connected in parallel to the emitter and collector of the transistor Q6. The base of the transistor Q5 is connected to the connection point of Cp1 via the resistor R11. Further, the preheating circuit PH has a diode D8 having an anode connected to a connection point between the capacitors Ct1 and Cp1, and a cathode connected to a connection point between the resistor R10 and the diode D10, and is connected in parallel to the capacitor Cp1 and has a cathode connected to the capacitor Cp1. It has a diode D9 connected to the connection point between Ct1 and Cp1.

The Emiless detection circuit EL extracts the induced voltage of the detection winding n3 attached to the output transformer LT1 provided in the load circuit Z as a voltage proportional to the voltage between both ends of the discharge lamp FL, and after half-wave rectification by the diode D14, Resistance R
The voltage is divided by a series circuit of R4 and R5 and smoothed by a capacitor C5 via a diode D11. The voltage across the capacitor C5 is the Zener diode Z
D1 and a resistor R7 are applied to a series circuit, and a connection point between the Zener diode ZD1 and the resistor R7 is connected to a transistor Q4.
Is connected. This transistor Q4 is npn
The collector is connected to the base of a pnp-type transistor Q3, and the base is connected to the collector of the transistor Q3. Further, the resistor R7 is connected between the emitter and the base of the transistor Q4. A resistor R8 is connected between the emitter and the base of the transistor Q3, and the voltage across the capacitor C5 is applied to a circuit composed of the transistors Q3, Q4 and the resistors R7, R8 via a series circuit of a diode D5 and a resistor R6. Applied. Further, the connection point between the emitter of the transistor Q3 and the resistor R8 is connected to the cathode of the diode D7 whose anode is connected to the base of the transistor Q6 of the preheating circuit PH, and to the cathode of the diode D6. The anode of the diode D6 is connected to the resistor R9 at the connection point between the diode D10 and the capacitor Ct1 in the preheating circuit PH.
Connected via

Next, the operation of the circuit shown in FIG. 21 will be described. When the power is turned on, a charging current flows from the rectifier DB through the resistor R3 to the capacitor C3 constituting the start-up circuit, and the potential of the capacitor C3 rises, so that the trigger element TD1
Is reached, the trigger element TD1 conducts, and the charge of the capacitor C3 is discharged through the resistor R2 and the secondary winding of the feedback transformer DT1 through the trigger element TD1, whereby a voltage is applied to the gate and source of the switching element Q2. Is applied to turn on the switching element Q2.

Since the smoothing capacitor C0 is not charged immediately after the power is turned on, when the switching element Q2 is turned on, the rectifier DB, the capacitor C1, the load circuit Z, the primary winding of the feedback transformer DT1, and the switching element. A current flows through a path of Q2-rectifier DB, and a current flows through a path of rectifier DB-smoothing capacitor C0-inductor L1-diode D1-primary winding of feedback transformer DT1-switching element Q2-rectifier DB. When the smoothing capacitor C0 and the capacitor C1 are charged and the current flowing through the primary winding of the feedback transformer DT1 decreases, no voltage is induced on the secondary winding, and the switching element Q2 is turned off. When the switching element Q2 is turned off, the regenerative current of the load circuit Z is applied to the load circuit Z-feedback transformer DT.
1 and the body diode of the switching element Q1-the capacitor C1-flows through the path of the load circuit Z, and the energy stored in the inductor L1 is reduced by the diode D1-
Primary winding of feedback transformer DT1-switching element Q1
Of the body diode-smoothing capacitor C0. Thereafter, the energy stored in the feedback transformer DT1 is released, so that a reverse voltage is induced in the secondary winding of the feedback transformer DT1, and the switching element Q1 is turned on.

When the switching element Q1 is turned on, a current flows through the path of the capacitor C1, the switching element Q1, the primary winding of the feedback transformer DT1, the load circuit Z, and the capacitor C1, using the capacitor C1 as a power supply. When the capacitor C1 is discharged, the current flowing through the primary winding of the feedback transformer DT1 decreases, and no voltage is induced on the secondary winding, so that the switching element Q1 is turned off and the load circuit Z-
Capacitor C1-Smoothing capacitor C0-Inductor L1
-Diode D1-Path of Load Circuit Z and Load Circuit Z-
Capacitor C1-Capacitor C2-Switching element Q
A current flows through the body diode of No. 2, the primary winding of the feedback transformer DT1, and the path of the load circuit Z. Thereafter, the energy stored in the feedback transformer DT1 is released, so that a reverse voltage is induced in the secondary winding of the feedback transformer DT1, and the switching element Q2 is turned on again. By repeating such an operation, switching elements Q1, Q2
Are alternately turned on and off, and an alternating current flows through the load circuit Z. Such an operation is hereinafter referred to as oscillation of the inverter circuit INV.

As is apparent from the above operation, when the switching element Q2 is turned on, the smoothing capacitor C0 is charged through the inductor L1, and when the switching element Q2 is turned off, the energy released from the inductor L1 is smoothed through the body diode of the switching element Q1. Since the capacitor C0 is accumulated, this operation has the same function as that of the step-down chopper type active filter, and the voltage across the capacitor C0 is sufficiently lower than the peak voltage of the output voltage of the rectifier DB.

When the inverter circuit INV starts oscillating, a voltage applied to the gate and source of the switching element Q2 to turn on the switching element Q2 is a series circuit of a resistor R10, a diode D10, a capacitor Ct1, and a capacitor Cp1. And the capacitors Ct1 and Cp1 are charged. Since the capacitor Ct1 is larger than the capacitance of the capacitor Cp1,
The potential at the connection point of the capacitors Ct1 and Cp1 rises in a relatively short time, turning on the transistors Q5 and Q6,
The gate and source of the switching element Q2 are short-circuited to turn off the switching element Q2. Therefore, the resistance R1
By appropriately setting the time constant of the integrating circuit composed of 0, the diode D10, and the capacitors Ct1 and Cp1,
The on-period of the switching element Q2 can be made shorter than when the self-excited operation is performed. That is, since the ON period of the switching element Q2 is shortened, the AC power supply V
The energy supplied to the inverter circuit INV from "in" decreases, and the on-period of the switching element Q2 is shortened to shorten the on / off cycle of the switching elements Q1 and Q2. And the impedance of the resonance circuit (consisting of the leakage inductance and the capacitor C4) included in the load circuit Z increases, and as a result, the power supplied to the discharge lamp FL decreases. That is, the discharge lamp FL
A preheating current can be supplied to the hot cathode (filament) of the first embodiment.

After the power is turned on, the capacitor Ct1 is gradually charged with the oscillation of the inverter circuit INV.
As shown in (a), the voltage at both ends increases, so that the current stops flowing in the integrating circuit. If the voltage across the capacitor Ct1 increases, the potential at the connection point between the capacitors Ct1 and Cp1 decreases, so that the base potential of the transistor Q5 decreases and the transistors Q5 and Q6 are kept off. That is, due to the operation of the preheating circuit PH, the ON period of the switching element Q2 gradually increases from the power-on as shown in FIG. 22B, so that the transistors Q5 and Q6 of the preheating circuit PH are finally kept off. To become and,
The other control stops and becomes equal to the ON period during the steady operation. When the preheating by the preheating circuit PH is completed, the oscillation frequency of the inverter circuit INV becomes low and approaches the resonance frequency of the resonance circuit included in the load circuit Z.
As shown in (c), the voltage applied to the discharge lamp FL increases, and the discharge lamp FL is turned on.

In the above-described operation, only the case where the output voltage of the rectifier DB is used as the power supply of the inverter circuit INV has been described. The higher voltage is the power supply of the inverter circuit INV. When the absolute value of the voltage of the AC power supply Vin is higher than the voltage across the smoothing capacitor C0, it corresponds to the vicinity of the peak of the output voltage of the rectifier DB, and is called a peak, and the opposite relationship is called a valley. As described above, the inverter circuit INV oscillates using the output of the rectifier DB as a power source in the peak portion, whereas the valley portion operates using the smoothing capacitor C0 as the power source as described below.
Here, the smoothing capacitor C
Since the peak value of the charging current flowing to 0 is proportional to the output voltage of the rectifier DB, a high power factor can be obtained in the above-described circuit.

Thus, in the valley, when the switching element Q2 is turned on, the smoothing capacitor C0, the capacitor C1, the load circuit Z, the primary winding of the feedback transformer DT1, the switching element Q2, the diode D3, and the inductor L1-smoothing. A current flows through the path of the capacitor C0. When the switching element Q2 is turned off, the regenerative current from the load circuit Z is applied to the load circuit Z, the primary winding of the feedback transformer DT1, the body diode of the switching element Q1, the capacitor C1, the path of the load circuit Z, or the load circuit Z. The current flows through the path of the primary winding of the feedback transformer DT1, the body diode of the switching element Q1, the capacitor C2, the rectifier DB, the capacitor C1, and the load circuit Z. By passing through such a path, an input current from the AC power supply Vin to the rectifier DB can flow even in the valley, and harmonics can be reduced.

Thereafter, when the switching element Q1 is turned on, the capacitor C1-the switching element Q1-the primary winding of the feedback transformer DT1-the load circuit Z-the capacitor C1
The current flows through the path. Further, the switching element Q1
Is turned off, the load circuit Z-capacitor C1-smoothing capacitor C0-inductor L1-diode D1-path of load circuit Z and load circuit Z-capacitor C1-capacitor C2-body diode of switching element Q2-
A current flows through the primary winding of the feedback transformer DT1 and the path of the load circuit Z. Thereafter, since the switching element Q2 is turned on again, the switching elements Q1 and Q2 are turned on and off alternately by repeating the above-described operation, and the load circuit Z
An alternating current flows through

As described above, the AC power supply Vi
n to the rectifier DB, and this input current flows at a high frequency in accordance with the on / off of the switching elements Q1 and Q2.
By inserting a high-frequency filter that blocks the on / off frequency of the switching elements Q1 and Q2 between B and B, it is possible to suppress the high frequency from flowing from the inverter circuit INV to the AC power supply Vin, and as a result, Harmonic distortion of the input current from the AC power supply Vin can be suppressed. Moreover, as described above, since the peak value of the charging current to the smoothing capacitor C0 is proportional to the output voltage of the rectifier DB, the envelope of the charging current becomes similar to the output voltage of the rectifier DB, and the high power factor Can be obtained.

In the circuit configuration shown in FIG. 21, even if the smoothing capacitor C0 is not charged immediately after the power is turned on, the ON period of the switching element Q2 immediately after the power is turned on can be shortened by the preheating circuit PH. In addition, it is possible to prevent the inrush current due to the charging current to the smoothing capacitor C0 from flowing.

When the voltage across the smoothing capacitor C0 is near zero, the energy stored in the inductor L1 increases. Therefore, the period in which the energy stored in the inductor L1 is released is longer than the period in which the regenerative current of the load circuit Z flows. become longer. Here, the current due to the energy stored in the inductor L1 and the regenerative current of the load circuit Z are equal to the switching element Q
1 body diode. Assuming that the switching element Q2 is turned on during a period in which a current is flowing through the body diode of the switching element Q1, the reverse recovery time of the body diode of the switching element Q1 is the same as the body diode of the switching element Q1 and the switching element Q2. The current flows in the direction, and as a result, both ends of the series circuit of the switching elements Q1 and Q2 conduct, and an excessive current (a so-called through current) flows. However, in the configuration shown in FIG. 21, since the primary winding of feedback transformer DT1 is inserted in the path for discharging the stored energy of inductor L1, switching is performed while current flows through the body diode of switching element Q1. Element Q
2 is not turned on, and consequently, even if a current flows through the body diode of the switching element Q1 for a longer period of time than during the normal operation as immediately after power-on,
It is possible to prevent a through current from flowing through a series circuit of the two switching elements Q1 and Q2.

In the load circuit Z, the discharge lamp FL
Is in the Emiless state or the discharge lamp FL is detached, the output transformer LT1 is turned on more than when the discharge lamp FL is steadily lit.
, The voltage across the secondary winding n2 rises, and as a result, the voltage across the detection winding n3 also rises. That is, since the voltage across the capacitor C5 increases, when the voltage exceeds the breakover voltage of the Zener diode ZD1, the Zener diode ZD1 conducts and the transistor Q4 turns on. When the transistor Q4 is turned on, the capacitor C5 and the diode D5
Resistor R6-emitter-base of transistor Q3-collector-emitter of transistor Q4-capacitor C5
, And the transistor Q3 is turned on. At this time, current also flows through the path between the emitter / collector of the transistor Q3 and the base / emitter of the transistor Q4, and the ON state of the transistors Q3 and Q4 is latched. This latch state continues as long as a current capable of maintaining on is supplied from the capacitor C5. here,
The resistors R7 and R8 are provided for protection.

As described above, transistors Q3 and Q4
Is turned on, the transistor Q6 connected to the transistors Q3 and Q4 via the diode D7 is turned on. As a result, the switching element Q2 is turned off and the oscillation of the inverter circuit INV stops. At this time,
Capacitor Ct through resistor R9 and diode D6
Since the charges of Cp1 and Cp1 are discharged, the preheating circuit PH is reset to the same state as immediately after the power is turned on.

The transistors Q3 and Q3 depend on the Emiless state.
When Q4 is turned on and the oscillation of the inverter circuit INV stops, the charging current stops flowing through the capacitor C5, and the voltage across the capacitor C5 decreases. Thus, the stopped state of the inverter circuit INV is maintained until the transistors Q3 and Q4 cannot be maintained in the on state. When the voltage between both ends of the capacitor C5 decreases and the ON state of the transistors Q3 and Q4 cannot be maintained, the starting circuit operates to restart the inverter circuit INV, and the operation of the preheating circuit PH starts. Such an operation is repeated while the Emiless state continues, and the inverter circuit INV intermittently oscillates.

On the other hand, when the discharge lamp FL is removed, the capacitor C4 included in the load circuit Z is also separated from the circuit, and the resonance circuit does not function. Therefore, once the oscillation of the inverter circuit INV is stopped, Even if the starting circuit operates, the oscillation of the inverter circuit INV does not start, and the oscillation of the inverter circuit INV stops until the next discharge lamp FL is mounted.

Emiless detection circuit E operating as described above
By providing L, the inverter circuit INV intermittently oscillates in the Emiless state, and as a result, the discharge lamp FL blinks, so that the user is notified that the discharge lamp FL is at the end of its life. In addition, it is possible to reduce the stress on the circuit caused by the half-wave current flowing in the Emiless state. In the case of the intermittent oscillation of the inverter circuit INV in the Emiless state, the waveforms of the respective parts are as shown in FIG. FIG. 23A shows the voltage between both ends of the capacitor C5. At time t0, the capacitor enters a emiless state, and a charging current flows from the detection winding n3 to the capacitor C5. The breakover voltage VZD1 of ZD1 has been reached. At this time, transistors Q3 and Q
4 is turned on and the oscillation of the inverter circuit INV stops as shown in FIG. 23C, so that the voltage across the capacitor C5 gradually decreases. In addition, transistors Q3 and Q
4 turns on, the capacitor Ct1 of the preheating circuit PH is discharged. Therefore, as shown in FIG. 23B, the voltage across the capacitor Ct1 is maintained at almost 0 V during the stop period of the inverter circuit INV.

As shown in FIG. 23 (a), at time t1, the voltage across capacitor C5 decreases and transistor Q
23, when the ON state of Q4 cannot be maintained.
As shown in (c), the inverter circuit INV is activated, and the preheating circuit PH is also activated. Therefore, as shown in FIG. 23B, the voltage between both ends of the capacitor Ct1 gradually increases, and the off period of the switching element Q2 is shortened.
As shown in (c), the output of the inverter circuit INV also increases. If the Emiless state continues, the voltage between both ends of the capacitor C5 rises again as shown in FIG. 23A, so that the inverter circuit INV stops again. Thus, the inverter circuit INV repeats the oscillation and the stop, and as a result, the discharge lamp FL blinks.

In the above-described configuration, the inverter circuit INV intermittently oscillates at the end of the life. Therefore, if the discharge lamp FL at the end of the life is removed and a normal discharge lamp FL is mounted again, the discharge lamp FL is automatically turned on. Can be turned on.
That is, since the inverter circuit INV operates as a so-called self-recovery type, even if external noise is applied to the capacitor C5 or the base of the transistor Q4 and the inverter circuit INV malfunctions and stops, the inverter circuit INV does not need to be turned on again.
There is an advantage that the oscillation of V is automatically restored.

As a power supply, as shown in FIG. 24, the rectifier DB in the power supply shown in FIG.
A diode D2 having an anode connected to a connection point between the capacitor C1 and the switching element Q1 and a cathode connected to a connection point between the switching element Q1 and the smoothing capacitor C0, and a power factor improving impedance element connected in parallel with the diode D2. A configuration in which a capacitor C6 is added is known. In this configuration, the operation from power-on to the oscillation of the inverter circuit INV is almost the same as the circuit configuration shown in FIG.

In a normal operation, when the current is in a valley, the inverter circuit INV operates using the smoothing capacitor C0 as a power supply. That is, when the switching element Q2 is turned on,
Smoothing capacitor C0-capacitor C6-capacitor C1
A resonance current flows through the path of the load circuit Z, the primary winding of the feedback transformer DT1, the switching element Q2, the diode D3, the inductor L1, and the smoothing capacitor C0, during which the capacitor C6 is charged. When the capacitor C6 is charged and the sum of the output voltage of the rectifier DB and the voltage across the capacitor C6 reaches the voltage across the smoothing capacitor C0, the resonance current in the above path stops flowing, and the rectifier DB-capacitor C1-load circuit A current flows through the path of the Z-primary winding of the feedback transformer DT1, the switching element Q2, and the rectifier DB. In short, a period during which the capacitor C6 is charged and a period during which the input current from the AC power supply Vin to the rectifier DB flows during the ON period of the switching element Q2. Here, the higher the output voltage of the rectifier DB, the higher the AC power supply V
The ratio of the period during which the input current flows from in to the rectifier DB increases.

When the switching element Q2 is turned off, the regenerative current from the load circuit Z is divided into the load circuit Z, the primary winding of the feedback transformer DT1, the body diode of the switching element Q1, the capacitor C2, the rectifier DB, and the capacitor C1.
-Flows on the path of the load circuit Z; That is, by passing through this path, the input current from the AC power supply Vin to the rectifier DB flows in the valley. Since the peak value of this current flows in a magnitude substantially proportional to the absolute value of the voltage of the AC power supply Vin, as in the case of the peak, a high power factor can be obtained.

When the switching element Q1 is turned on, the capacitor C1-capacitor C6-switching element Q1-feedback transformer DT1
When the resonance current flows through the path of the secondary winding-load circuit Z-capacitor C1, and thereafter the charge of the capacitor C6 decreases to zero, the capacitor C1-diode D2-switching element Q1-primary winding of the feedback transformer DT1 A resonance current flows through the path of the load circuit Z and the capacitor C1. Further, when the switching element Q1 is turned off, the load circuit Z
Will flow through the path of load circuit Z-capacitor C1-diode D2-smoothing capacitor C0-inductor L1-diode D1-load circuit Z.

By repeating the above operation, a high-frequency voltage is applied to the load circuit Z, and the discharge lamp FL included in the load circuit Z can be turned on at a high frequency.
In the circuit configuration shown in FIG. 24, by adding a parallel circuit of a capacitor C6 and a diode D2 to the circuit configuration of FIG.
The period during which the input current flows through B can be made longer than that of the circuit configuration of FIG. 21, and as a result, harmonic distortion can be further reduced than that of the circuit configuration of FIG. In addition, since the peak value of the input current can be made to flow substantially in proportion to the absolute value of the input voltage of the AC power source Vin, a high power factor can be obtained.

The operation of the crest in the circuit configuration shown in FIG. 24 is the same as that of the circuit shown in FIG. That is, when the switching element Q2 is turned on, a current flows through a path passing through the load circuit Z and a path passing through the smoothing capacitor C0 and the inductor L1, and when the switching element Q2 is turned off, the inductor L1-the primary winding of the feedback transformer DT1. A regenerative current flows through the path of the body diode of the switching element Q1, the smoothing capacitor C0, and the inductor L1. When the switching element Q1 is turned on, the capacitor C1-the capacitor C6-the switching element Q1-
The primary winding of the feedback transformer DT1-the resonance current flows through the path of the load circuit Z-the capacitor C1 and the charge of the capacitor C6 decreases, so that the capacitor C1-the diode D2-the switching element Q1-the primary winding of the feedback transformer DT1- A resonance current flows through the path of the load circuit Z-the capacitor C1. Further, when the switching element Q1 is turned off, a current flows through the path of the load circuit Z, the capacitor C1, the diode D2, the smoothing capacitor C0, the inductor L1, the diode D1, and the load circuit Z.

As a power supply device, there is also known a circuit configuration to which a pulse width setting circuit PW is added as shown in FIGS. FIG. 25 is a circuit diagram of the circuit of FIG.
FIG. 26 is obtained by adding a pulse width setting circuit PW to the circuit of FIG. The pulse width setting circuit PW controls the ON time of the switching element Q2 similarly to the preheating circuit PH.
Includes an npn-type transistor Q7 having a collector and an emitter connected to the base and collector of a transistor Q6 for controlling the gate potential of the switching element Q2.
The pulse width setting circuit PH includes a series circuit of a resistor R13 and a capacitor C8 connected between both ends of the control power supply Vcc. Connected.
The collector and the emitter of the transistor Q8 are connected in parallel to the capacitor C8. A series circuit of two resistors R14 and R15 is connected in parallel as a DC impedance element to the switching element Q2.
The base of the transistor Q8 is connected to the connection point of the transistors 14 and R15. A capacitor C7 is connected in parallel to the base and the emitter of the transistor Q8.

In the pulse width setting circuit PW, the voltage across the capacitor C7 changes in accordance with the on / off state of the switching element Q2, so that the transistor Q8 is turned on / off in accordance with the on / off state of the switching element Q2. When the transistor Q8 is turned on, the capacitor C8 is discharged, and when the transistor Q8 is turned off, the resistor R
13, the capacitor C8 is charged.

That is, when the switching element Q2 turns on, the transistor Q8 turns off and the capacitor C
8 is charged, and after a lapse of a predetermined time determined by the resistor R13 and the capacitor C8, the transistor Q7 is turned on, turning on the transistor Q6, and consequently turning off the switching element Q2. As described above, the ON period of the switching element Q2 is determined by the time constant of the integrating circuit including the resistor R13 and the capacitor C8. When the switching element Q2 is turned off, the transistor Q7 is turned on, so that the capacitor C8 is discharged, so that the switching element Q2 is turned on next time. Thus, the pulse width setting circuit PW determines the ON period of the switching element Q2.

[0038]

Each of the power supply devices shown in FIGS. 21, 24, 25, and 26 has a load circuit Z when in the Emiless state or when the discharge lamp FL comes off.
Rapidly changes, the power supply becomes excessive with respect to the power consumption, and the oscillation of the inverter circuit INV stops with the voltage across the smoothing capacitor C0 rising. As in the Emiless state, the inverter circuit INV
Is restarted after stopping, the starting voltage is applied from the capacitor C3 to the gate of the switching element Q2, and a resonance current can flow through a path passing through the capacitor C1, the load circuit Z, the feedback transformer DT1, and the switching element Q2. Since the voltage across the smoothing capacitor C0 is high, a sufficient current cannot flow through the path of the smoothing capacitor C0, the inductor L1, the diode D1, the primary winding of the feedback transformer DT1, and the switching element Q2 ( In some cases, a secondary output sufficient to drive the switching elements Q1 and Q2 cannot be obtained in the feedback transformer DT1. As a result, after the Emiless state is detected, the discharge lamp FL may not be automatically turned on again.

Moreover, the capacitor Ct1 of the preheating circuit PH is discharged when the oscillation of the inverter circuit INV is stopped due to the Emiless state or the discharge lamp FL coming off, so that the preheating circuit PH shortens the ON period of the switching element Q2. As a result, the current flowing through the primary winding of the feedback transformer DT1 is further reduced. Therefore, the inverter circuit INV
In the intermittent oscillation, when the inverter circuit INV shifts from the stop state to the oscillation state, the inverter circuit INV may not be able to be activated even though the activation circuit is operating.

In particular, in the power supply device shown in FIGS. 25 and 26, if the Emiless detection circuit EL operates and the switching element Q2 is turned off due to the Emiless state or the discharge lamp FL coming off, the DC output terminal of the rectifier DB In the meantime,
Capacitor C1 with infinite DC impedance
And a series circuit of a load circuit Z having zero DC impedance and a feedback transformer DT1, and a resistor R1
4 and R15, a capacitor C
In this state, the operation of the inverter circuit INV is stopped in a state where a voltage higher than that in the normal operation is applied to the inverter 1. When the voltage across the capacitor C1 is high as described above, when the switching element Q2 is turned on by restarting, the capacitor C1-the load circuit Z-the primary winding of the feedback transformer DT1-
The current flowing through the path of the switching element Q2 becomes small, and the smoothing capacitor C0
-Since the current flowing through the path of the inductor L1-the primary winding of the feedback transformer DT1-the switching element Q2 is also small,
As a result, it is more likely that the inverter circuit INV cannot be started. In short, the resistor R1 is connected to the switching element Q2.
The fact that the series circuit of R4 and R15 are connected in parallel causes the restart to be difficult.

Further, in addition to the above-described problem, the power supply device shown in FIG. 26 operates so as to take in the input current to a part of the resonance current of the inverter circuit INV. When the input power becomes excessive with respect to the output power at the time of light load as in the case of the above, the voltage between both ends of the smoothing capacitor C0 and the capacitor C1 tends to increase more than the circuit configuration shown in FIG. Since the rise in the voltage between both ends of the capacitor C1 at the time is large, it is more difficult to restart than the circuit configuration of FIG.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a power supply device capable of easily returning an inverter circuit to a normal operation state when an abnormal state of a load is released. It is in.

[0043]

According to the first aspect of the present invention, there is provided a rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier and supplying output power to a load circuit, and limiting the output power of the inverter circuit. And control the other control circuit to temporarily stop the operation of the inverter circuit when an abnormality is detected in the load circuit, and then control the other control circuit to return to the output power during normal operation An inverter circuit, which is connected between the output terminals of the rectifier and alternately turns on and off, and a series circuit of two switching elements, and alternately switches the switching elements by feeding back part of the output power. A feedback transformer to be turned on and off, and a series circuit of a load circuit and a primary winding of the feedback transformer are connected between one of the DC output terminals of the rectifier and a connection point of both switching elements. And a smoothing capacitor in which a series circuit of one of the switching element, the inductance element, and the primary winding of the feedback transformer is connected between the output terminals of the rectifier and partially smoothes the output voltage of the rectifier. And a discharge impedance element for discharging the electric charge of the smoothing capacitor when the inverter circuit is stopped.

According to a second aspect of the present invention, there is provided a rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier for supplying output power to a load circuit, and a function for limiting the output power of the inverter circuit. Control circuit and an abnormality detection circuit that controls the other control circuit so as to temporarily stop the operation of the inverter circuit when an abnormality of the load circuit is detected, and then controls the other control circuit to return to the output power during normal operation. An inverter circuit connected between the output terminals of the rectifier, and a series circuit of two switching elements that are alternately turned on and off; a feedback transformer that alternately turns on and off the switching elements by feeding back part of the output power; A DC circuit in which a series circuit of a load circuit and a primary winding of a feedback transformer is connected between one of the DC output terminals of the rectifier and a connection point of both switching elements. And a series circuit of one of the switching element, the inductance element and the primary winding of the feedback transformer is connected between the output terminals of the rectifier, and a series circuit of the inductance element and the primary winding of the feedback transformer is formed. A smoothing capacitor connected between both ends of the other switching element for partially smoothing the output voltage of the rectifier, and one end on the rectifier side in a series circuit of a load circuit, a primary winding of a feedback transformer, and a DC cut capacitor, and both switchings; A diode inserted between the series circuit of elements with a polarity for flowing a charging current from the rectifier to the smoothing capacitor, and an impedance element connected in parallel with the diode for power factor improvement, and the smoothing capacitor is provided when the inverter circuit is stopped. And a discharge impedance element for discharging the electric charges.

According to a third aspect of the present invention, in the first or second aspect, the inductance element is an inductor.

According to a fourth aspect of the present invention, in the first or second aspect, the inductance element is an inductance component included in the load circuit.

According to a fifth aspect of the present invention, there is provided a rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier for supplying output power to a load circuit, and a function for limiting the output power of the inverter circuit. Control circuit and an abnormality detection circuit that controls the other control circuit so as to temporarily stop the operation of the inverter circuit when an abnormality of the load circuit is detected, and then controls the other control circuit to return to the output power during normal operation. An inverter circuit connected between the output terminals of the rectifier, and a series circuit of two switching elements that are alternately turned on and off; a feedback transformer that alternately turns on and off the switching elements by feeding back part of the output power; A DC circuit in which a series circuit of a load circuit and a primary winding of a feedback transformer is connected between one of the DC output terminals of the rectifier and a connection point of both switching elements. And a smoothing capacitor for connecting a series circuit of one switching element, an inductance element and a primary winding of a feedback transformer between output terminals of the rectifier to partially smooth an output voltage of the rectifier, and the one switching element A DC impedance element connected in parallel with the DC impedance, and a voltage dividing impedance element for forming a voltage dividing circuit together with the DC impedance and suppressing a rise in voltage across the DC cut capacitor when the inverter circuit is stopped is added. It is.

According to a sixth aspect of the present invention, there is provided a rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier for supplying output power to a load circuit, and a function for limiting the output power of the inverter circuit. Control circuit and an abnormality detection circuit that controls the other control circuit so as to temporarily stop the operation of the inverter circuit when the abnormality of the load circuit is detected, and then controls the other control circuit to return to the output power during normal operation. An inverter circuit connected between the output terminals of the rectifier, and a series circuit of two switching elements that are alternately turned on and off; a feedback transformer that alternately turns on and off the switching elements by feeding back part of the output power; A DC circuit in which a series circuit of a load circuit and a primary winding of a feedback transformer is connected between one of the DC output terminals of the rectifier and a connection point of both switching elements. And a series circuit of one of the switching element, the inductance element, and the primary winding of the feedback transformer are connected between the output terminals of the rectifier, and a series circuit of the inductance element and the primary winding of the feedback transformer is formed. A smoothing capacitor connected between both ends of the other switching element for partially smoothing the output voltage of the rectifier, and one end on the rectifier side in a series circuit of a load circuit, a primary winding of a feedback transformer, and a DC cut capacitor, and both switching circuits; A diode inserted between the rectifier and the series circuit of the element with a polarity for flowing a charging current from the rectifier to the smoothing capacitor, an impedance element for power factor improvement connected in parallel to the diode, and connected in parallel to the one switching element. And a DC impedance element. Inhibit voltage-dividing impedance elements an increase in the voltage across the capacitor for DC blocking at the time of stop of the capacitor circuit in which is formed by addition.

According to a seventh aspect of the present invention, in the fifth or sixth aspect, the inductance element is an inductor.

According to an eighth aspect of the present invention, in the fifth or sixth aspect, the inductance element is an inductance component included in the load circuit.

According to a ninth aspect of the present invention, there is provided a rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier for supplying output power to a load circuit, and a function for limiting the output power of the inverter circuit. Control circuit and an abnormality detection circuit that controls the other control circuit so as to temporarily stop the operation of the inverter circuit when the abnormality of the load circuit is detected, and then controls the other control circuit to return to the output power during normal operation. An inverter circuit connected between the output terminals of the rectifier, and a series circuit of two switching elements that are alternately turned on and off; a feedback transformer that alternately turns on and off the switching elements by feeding back part of the output power; A DC circuit in which a series circuit of a load circuit and a primary winding of a feedback transformer is connected between one of the DC output terminals of the rectifier and a connection point of both switching elements. And a smoothing capacitor in which a series circuit of one of the switching element, the inductance element and the primary winding of the feedback transformer is connected between the output terminals of the rectifier and partially smoothes the output voltage of the rectifier. However, it has a function of shortening the on-time of the switching element as compared with the normal operation, and has a separate capacitor connected in such a manner that the on-time of the switching element becomes longer as the voltage between both ends is higher. At the time when the output power of the inverter circuit is restored, the voltage across the other control capacitor is set higher than immediately after the power is turned on.

A rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier for supplying output power to a load circuit, and a function for limiting the output power of the inverter circuit. Control circuit and an abnormality detection circuit that controls the other control circuit so as to temporarily stop the operation of the inverter circuit when the abnormality of the load circuit is detected, and then controls the other control circuit to return to the output power during normal operation. An inverter circuit connected between the output terminals of the rectifier, and a series circuit of two switching elements that are alternately turned on and off; a feedback transformer that alternately turns on and off the switching elements by feeding back part of the output power; A series circuit consisting of a load circuit and a primary winding of a feedback transformer is connected between one of the DC output terminals of the rectifier and a connection point between the two switching elements. And a series circuit of a switching capacitor, an inductance element and a primary winding of a feedback transformer connected between an output terminal of the rectifier and a series circuit of an inductance element and a primary winding of the feedback transformer. Is connected between both ends of the other switching element, and a smoothing capacitor for partially smoothing the output voltage of the rectifier, and one end on the rectifier side in a series circuit of a load circuit, a primary winding of a feedback transformer, and a DC cut capacitor. A diode inserted with a polarity to flow a charging current from the rectifier to the smoothing capacitor between the series circuit of the switching elements,
A power factor improving impedance element connected in parallel with the diode, and the other control circuit has a function of shortening the on time of the switching element compared with the normal operation. The voltage at both ends of the other control capacitor is set higher than immediately after the power is turned on at the time when the abnormality detection circuit restores the output power of the inverter circuit. .

According to an eleventh aspect, in the ninth or tenth aspect, the inductance element is an inductor.

According to a twelfth aspect of the present invention, in the ninth or tenth aspect, the inductance element is an inductance component included in the load circuit.

A rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier for supplying output power to a load circuit, and a function for limiting the output power of the inverter circuit. And an abnormality detection circuit that controls the other control circuit so as to temporarily reduce the output power of the inverter circuit when the abnormality of the load circuit is detected, and then controls the other control circuit to return to the output power during normal operation. A series circuit of two switching elements connected between the output terminals of the rectifier and alternately turned on and off, and a feedback transformer for alternately turning on and off the switching elements by feeding back part of the output power. A series circuit of the load circuit and the primary winding of the feedback transformer is connected between one of the DC output terminals of the rectifier and the connection point of both switching elements. A series circuit of one of a switching element, an inductance element, and a primary winding of a feedback transformer is connected between an output terminal of the rectifier and a smoothing capacitor for partially smoothing an output voltage of the rectifier; The circuit has a function of shortening the on-time of the switching element as compared with the time of normal operation, and further includes a bypass capacitor connected to increase the on-time of the switching element as the voltage between both ends is higher, and includes an abnormality detection circuit. Is to set the voltage across the other capacitor at the time when the output power of the inverter circuit is restored to be higher than immediately after the power is turned on.

According to a fourteenth aspect of the present invention, there is provided a rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier for supplying output power to a load circuit, and a function for limiting the output power of the inverter circuit. And an abnormality detection circuit that controls the other control circuit so as to temporarily reduce the output power of the inverter circuit when the abnormality of the load circuit is detected, and then controls the other control circuit to return to the output power during normal operation. A series circuit of two switching elements connected between the output terminals of the rectifier and alternately turned on and off, and a feedback transformer for alternately turning on and off the switching elements by feeding back part of the output power. A series circuit of a load circuit and a primary winding of a feedback transformer is connected between one of the DC output terminals of the rectifier and a connection point of both switching elements. Tsu and capacitor preparative, of one switching element and an inductance element and a feedback transformer 1
A series circuit with the secondary winding is connected between the output terminals of the rectifier, and a series circuit with the inductance element and the primary winding of the feedback transformer is connected between both ends of the other switching element to partially smooth the output voltage of the rectifier. A smoothing capacitor,
A rectifier is inserted between one end on the rectifier side and a series circuit of both switching elements in a series circuit of a load circuit, a primary winding of a feedback transformer, and a DC cut capacitor with a polarity for flowing a charging current from the rectifier to the smoothing capacitor. A diode and a power factor improving impedance element connected in parallel to the diode, and the other control circuit has a function of shortening the on-time of the switching element as compared with the normal operation. Equipped with another control capacitor connected to extend the on-time of the element, and set the voltage across the other control capacitor higher than immediately after power-on when the abnormality detection circuit restores the output power of the inverter circuit. Is what you do.

According to a fifteenth aspect, in the thirteenth or fourteenth aspect, the inductance element is an inductor.

According to a sixteenth aspect, in the thirteenth or fourteenth aspect, the inductance element is an inductance component included in the load circuit.

[0059]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) As shown in FIG. 1, this embodiment has basically the same configuration as that shown in FIG. 21, and has a smoothing capacitor C0 and an inductor. The only difference is that a discharge resistor Rd as a discharge impedance element is connected in parallel to a series circuit with L1. The discharge resistor Rd is set to a resistance value that does not affect normal operation, and the smoothing capacitor Cd is kept off while the switching element Q2 is kept off by the Emiless detection circuit EL.
The resistance value is set to a value such that 0 can be discharged. Other configurations and operations are the same as those of the conventional configuration shown in FIG.

According to the configuration of this embodiment, when the Emiless detection circuit EL detects the Emiless state or the disconnection state of the discharge lamp FL and the switching element Q2 is turned off, the capacitor C5 is discharged and the switching element Q2 is discharged.
The charge of the smoothing capacitor C0 will be discharged through the discharge resistor Rd until the start of the second operation. Therefore, the capacitor C5 is discharged and the preheating circuit PH
When the switching element Q2 is restarted by the start-up circuit in a state where the capacitors Ct1 and Cp1 provided in the power supply are discharged, the voltage across the smoothing capacitor C0 is reduced. -Inductor L-diode D1-feedback transformer DT1 1
A current large enough to oscillate the inverter circuit INV can flow through the path between the next winding and the switching element Q2. That is, the restart of the inverter circuit INV becomes easy. Here, if the relationship between the resistance value of the discharge resistor Rd and the discharge time of the capacitor C5 is appropriately selected, the charge of the smoothing capacitor C0 can be reduced to almost zero at the time of restarting. The same large current can flow through the primary winding of the feedback transformer DT1. Moreover, since only the discharge resistor Rd is added to the conventional configuration, it is possible to inexpensively realize a configuration that enhances the startup performance in restarting the inverter circuit INV.

When the Emiless detection circuit EL detects the Emiless state and the inverter circuit INV performs intermittent oscillation, the waveforms of the respective parts are as shown in FIG. FIG. 2A shows the voltage between both ends of the capacitor C5. At time t0, the capacitor C5 enters an emiless state, and the detection coil n3 is connected to the capacitor C5.
As a result, the voltage across the capacitor C5 rises and reaches the breakover voltage VZD1 of the Zener diode ZD1. At this time, the transistor Q
3 and Q4 are turned on and the oscillation of the inverter circuit INV is stopped as shown in FIG.
Gradually decreases. Also, the transistor Q
Since the capacitor Ct1 of the preheating circuit PH is discharged when Q3 and Q4 are turned on, as shown in FIG. 2B, the voltage across the capacitor Ct1 is maintained at almost 0V during the stop period of the inverter circuit INV. When the oscillation of the inverter circuit INV stops in this way, the smoothing capacitor C0 is discharged through the discharge resistor Rd as described above, and the voltage across the smoothing capacitor C0 gradually decreases as shown in FIG.

At time t1 when the voltage across the smoothing capacitor C0 approaches zero, if the voltage across the capacitor C5 drops and the transistors Q3 and Q4 cannot be kept on, the inverter circuit INV as shown in FIG. Is activated, and as shown in FIG. 2D, the voltage across the smoothing capacitor C0 increases, and the preheating circuit PH is activated. Therefore, as shown in FIG. 2B, the voltage across the capacitor Ct1 gradually increases, and the OFF period of the switching element Q2 becomes shorter, and the inverter circuit IN as shown in FIG. 2C.
The output of V also increases. If the Emiless state continues,
As shown in FIG. 2A, since the voltage across the capacitor C5 increases again, the inverter circuit INV stops again. Thus, the inverter circuit INV repeats the oscillation and the stop, and as a result, the discharge lamp FL blinks.

(Second Embodiment) This embodiment is similar to FIG.
As shown in FIG. 1, an anode is connected to the connection point between the rectifier DB and the capacitor C1 and a cathode is connected to the connection point between the switching element Q1 and the smoothing capacitor C0 in the configuration of the first embodiment shown in FIG. A diode D2 connected thereto is added, and a capacitor C6 connected in parallel to the diode D2 is added. In other words, the conventional configuration shown in FIG. 24 has a configuration in which a discharge resistor Rd is connected in parallel to a series circuit of the smoothing capacitor C0 and the inductor L1. The resistance value of the discharge resistor Rd is the first
Are set based on the same standard as that of the embodiment, and do not affect the normal operation, and the Emiless detection circuit EL
As a result, the smoothing capacitor C0 is discharged while the switching element Q2 is kept off, and at the time of restart, the current flowing through the primary winding of the feedback transformer DT1 through the smoothing capacitor C0 is sufficient to oscillate the inverter circuit INV. It is set to be on the order. Other configurations and operations are the same as those of the conventional configuration shown in FIG.

The effect of providing the discharge resistor Rd is the same as that of the first embodiment, and the Emiless detection circuit EL
When the inverter circuit INV is restarted after the operation of the inverter circuit INV, the smoothing capacitor C
The voltage between both ends of 0 has dropped, and just like immediately after power-on,
Smoothing capacitor C0-Inductor L-Diode D1-
Primary winding of feedback transformer DT1-switching element Q2
With this path, a current large enough to cause the inverter circuit INV to oscillate can flow. That is, the restart of the inverter circuit INV becomes easy. here,
If the relationship between the resistance value of the discharge resistor Rd and the discharge time of the capacitor C5 is appropriately selected, the smoothing capacitor C
0 can be reduced to almost zero. In this case, a current as large as that at the time of turning on the power is supplied to 1 of the feedback transformer DT1.
It becomes possible to flow to the next winding. Moreover, since only the discharge resistor Rd is added to the conventional configuration, it is possible to inexpensively realize a configuration that enhances the startup performance in restarting the inverter circuit INV.

(Third Embodiment) This embodiment is similar to FIG.
As shown in the figure, the second embodiment is different from the second embodiment in that the connection position of the cathode of the diode D1 constituting the partial smoothing circuit is changed. That is, in the second embodiment, the cathode of the diode D1 is connected to the load circuit Z and the feedback transformer DT1.
In this embodiment, the cathode of the diode D1 is connected to the connection point between the load circuit Z and the capacitor C1. Also, the second
In the embodiment, the inductor L1 is provided in the partial smoothing circuit. On the other hand, in the present embodiment, the inductor L1 is omitted, and the discharge resistor Rd is connected in parallel to the smoothing capacitor C0. In short, the output transformer LT1 provided in the load circuit Z instead of the inductor L1 forming the partial smoothing circuit
In addition, the inductance of the feedback transformer DT1 is used as the inductance element. By employing such a configuration, the inductor L1 can be reduced, and the inductor L1 can be reduced in response to the addition of the discharge resistor Rd. As a result, the number of components can be prevented from increasing or decreasing.
Other configurations and operations are the same as those of the second embodiment.

(Fourth Embodiment) This embodiment is different from FIG.
25, the only difference is that a voltage dividing resistor Rs as a voltage dividing impedance element is connected in parallel to the capacitor C1 with respect to the conventional configuration shown in FIG. The voltage dividing resistor Rs is set to a resistance value that does not affect the normal operation, and the resistors R14 and R1 are held while the switching element Q2 is kept off by the Emiless detection circuit EL.
5, the voltage applied to the inverter circuit INV is divided so as to be set to a resistance value that prevents the voltage across the capacitor C1 from rising more than during normal operation. Other configurations and operations are the same as those of the conventional configuration shown in FIG.

According to the configuration of this embodiment, when the Emiless detection circuit EL detects the Emiless state or the disconnection state of the discharge lamp FL and the switching element Q2 is turned off, the capacitor C5 is discharged and the switching element Q2 is restarted. In the meantime, the voltage across the capacitor C1 is
The power supply voltage to the inverter circuit INV is divided by the voltage dividing resistor Rs and the resistors R14 and R15. Here, the DC resistance of the load circuit Z and the primary winding of the feedback transformer DT1 is sufficiently smaller than the resistors R14 and R15 and the voltage dividing resistor Rs. Since the voltage across the capacitor C1 is the voltage across the voltage dividing resistor Rs, setting the voltage dividing resistor Rs appropriately according to the size of the resistors R14 and R15 prevents the voltage across the capacitor C1 from becoming excessive. Can be prevented.

In short, according to the configuration of the present embodiment, it is possible to suppress an increase in the voltage across the capacitor C1 during the period when the oscillation of the inverter circuit INV is stopped, so that the capacitor C5 is discharged and the preheating circuit PH With the capacitors Ct1 and Cp1 provided in
At the time when the switching element Q2 is restarted by the starting circuit, a current sufficient to oscillate the inverter circuit INV from the power supply through the path of the capacitor C1, the load circuit Z, the primary winding of the feedback transformer DT1, and the switching element Q2. Can be shed. That is, the restart of the inverter circuit INV becomes easy. Here, since only the voltage dividing resistor Rs is added to the conventional configuration, the inverter circuit INV
A configuration that enhances the start-up performance at the time of restart can be realized at low cost. In this embodiment, the capacitor C1
Need not be discharged, and the voltage dividing resistor Rs is connected to the capacitor C
1 only suppresses a rise in the voltage across the capacitor C1, and there is no need to flow the discharge current of the capacitor C1.
A resistor having a small rated power can be used for s, and a resistor that is less expensive can be used for the voltage dividing resistor Rs than the discharge resistor Rd used in the first to third embodiments.

(Fifth Embodiment) This embodiment is different from FIG.
As shown in FIG. 26, the point that a voltage dividing resistor Rs is connected in parallel to the capacitor C1 with respect to the conventional configuration shown in FIG.
The inductor Lf is connected to the AC input terminal of the rectifier DB, the capacitor Cf is connected between the DC output terminals of the rectifier DB, and the diode D11 is inserted between one (positive) DC output terminal of the rectifier DB and the diode D2. Are different. That is, the capacitor C is different from that of the fourth embodiment.
f, an inductor Lf, and a diode D11, a diode D2 having an anode connected to a connection point between the diode D11 and the capacitor C1, and a cathode connected to a connection point between the switching element Q1 and the smoothing capacitor C1.
And a capacitor C6 is connected in parallel with the diode D2.

The capacitor Cf and the inductor Lf form a filter circuit, which removes high frequency components from the input current from the AC power supply Vin to the rectifier DB. In other words, the filter circuit prevents the leakage of the high-frequency current from the inverter circuit INV to the AC power supply Vin. The diode D11 is provided to separate the filter circuit capacitor Cf so as not to affect the resonance operation of the inverter circuit INV.

The basic operation is the same as that of the conventional configuration shown in FIG. 26, and the function of the voltage dividing resistor Rs is the same as that of the fourth embodiment. In other words, the voltage dividing resistor Rs is set to a resistance value that does not affect normal operation, and is applied to the inverter circuit INV together with the resistors R14 and R15 while the switching element Q2 is kept off by the Emiless detection circuit EL. Of the capacitor C1 is set to a resistance value that prevents the voltage across the capacitor C1 from rising more than during normal operation.

The effect of providing the voltage dividing resistor Rs is the same as that of the fourth embodiment, and the Emiless detection circuit EL
When the switching element Q2 is turned off by detecting the Emiless state or the detached state of the discharge lamp FL, the capacitor C
5 is discharged and the switching element Q2 is activated again, the voltage between both ends of the capacitor C1 changes the power supply voltage to the inverter circuit INV from the voltage dividing resistor Rs and the resistor R1.
4 and R15, and the voltage is divided by the voltage dividing resistor Rs.
Is appropriately set according to the magnitudes of the resistors R14 and R15, it is possible to prevent the voltage across the capacitor C1 from becoming excessive.

As described above, it is possible to suppress an increase in the voltage across the capacitor C1 during the period when the oscillation of the inverter circuit INV is stopped, so that the capacitor C5 is discharged and the capacitor Ct provided in the preheating circuit PH is discharged.
1, when the switching element Q2 is restarted by the starting circuit in a state where Cp1 is discharged, an inverter circuit is provided from the power supply to the capacitor C1, the load circuit Z, the primary winding of the feedback transformer DT1, and the switching element Q2. IN
A current sufficient to oscillate V can flow. That is, the restart of the inverter circuit INV becomes easy.

(Sixth Embodiment) This embodiment relates to FIG.
As shown in FIG. 7, the connection relationship between the voltage dividing resistor Rs and the capacitor C1 is changed from the fifth embodiment shown in FIG. That is, in the fifth embodiment, the voltage dividing resistor Rs is connected in parallel to the capacitor C1, whereas in the present embodiment, the voltage dividing resistor Rs is connected in parallel to the series circuit of the diode D11 and the capacitor C1. ing. In this configuration, a diode D11 is inserted between the capacitor C1 and the voltage dividing resistor Rs, and the polarity of the diode D11 is such that the charge of the capacitor C1 is prevented from discharging through the voltage dividing resistor Rs. As a result, while the oscillation of the inverter circuit INV is stopped by the operation of the Emiless detection circuit EL, the charge of the capacitor C1 is reliably prevented from discharging through the resistor Rs, and the loss due to the resistor Rs is reduced to the fifth embodiment. It can be reduced than the form. Other configurations and operations are the same as those of the fifth embodiment.

(Seventh Embodiment) This embodiment is different from the embodiment shown in FIG.
As shown in FIG. 7, the connection relationship between the voltage dividing resistor Rs and the capacitor C1 is changed from the fifth embodiment shown in FIG. That is, in the fifth embodiment, the voltage dividing resistor Rs is connected in parallel to the capacitor C1, whereas in the present embodiment, the voltage dividing resistor Rs is connected in parallel to the series circuit of the diode D2 and the capacitor C1. ing. In this configuration, the diode D2 is inserted between the capacitor C1 and the voltage dividing resistor Rs. However, as in the fifth embodiment, if the resistance value of the voltage dividing resistor Rs is appropriately set, the Emiless detection is performed. While the oscillation of the inverter circuit INV is stopped by the operation of the circuit EL, it is possible to prevent the voltage across the capacitor C1 from becoming higher than that in the normal operation. Other configurations and operations are the same as those of the fifth embodiment.

(Eighth Embodiment) This embodiment is different from the embodiment shown in FIG.
As shown in FIG. 6, the connection position of the voltage dividing resistor Rs is changed from that of the fifth embodiment shown in FIG. That is, in the fifth embodiment, the voltage dividing resistor Rs is connected in parallel to the capacitor C1, whereas in the present embodiment, the voltage dividing resistor Rs is connected in parallel to the switching element Q1. When the Emiless detection circuit EL operates and the switching element Q2 is turned off, the DC impedance of the load circuit Z and the primary winding of the feedback transformer DT1 may be regarded as substantially zero. Are substantially equivalent to a state where the voltage dividing resistor Rs is connected in parallel to the capacitor C1. As a result, also in this embodiment, as in the fifth embodiment, if the resistance value of the voltage dividing resistor Rs is appropriately set, the oscillation of the inverter circuit INV is stopped by the operation of the Emiless detection circuit EL. It is possible to prevent the voltage between both ends of the capacitor C1 from becoming higher during the normal operation. Other configurations and operations are the same as those of the fifth embodiment.

(Ninth Embodiment) This embodiment is different from the ninth embodiment shown in FIG.
As shown by 0, the connection position of the cathode of the diode D1 is different from that of the fifth embodiment shown in FIG. That is, the cathode of the diode D1 is connected to the fifth
In the embodiment, the load circuit Z and the feedback transformer DT1
In contrast to the connection at the connection point with the next winding, in the present embodiment, it is connected at the connection point between the capacitor C1 and the load circuit Z. In this embodiment, the inductor L1 connected in series to the smoothing capacitor C0 is omitted. This configuration is a modification similar to the modification of the third embodiment with respect to the first embodiment.
The inductance of the output transformer LT1 and the feedback transformer DT1 provided in the load circuit Z is used. By employing the configuration of the present embodiment, the inductor L1 can be reduced, and the number of components can be reduced as compared with the fifth embodiment. Other configurations and operations are the same as those of the fifth embodiment.

(Tenth Embodiment) In the present embodiment, as shown in FIG. 11, the connection relationship between the voltage dividing resistor Rs and the capacitor C1 is changed from the ninth embodiment shown in FIG. It was done. That is, in the ninth embodiment,
While the voltage dividing resistor Rs is connected in parallel to the capacitor C1, in the present embodiment, the voltage dividing resistor Rs is connected to the diode D1.
1 and a capacitor C1 are connected in parallel to a series circuit.
In other words, the relationship between this embodiment and the ninth embodiment is the same as the relationship between the sixth embodiment and the fifth embodiment.

Therefore, in the configuration of the present embodiment, the diode D11 is inserted between the capacitor C1 and the voltage dividing resistor Rs, and the polarity of the diode D11 prevents the charge of the capacitor C1 from being discharged through the voltage dividing resistor Rs. As a result, while the oscillation of the inverter circuit INV is stopped by the operation of the Emiless detection circuit EL, the charge of the capacitor C1 is reliably prevented from discharging through the resistor Rs, and the loss due to the resistor Rs is reduced to the ninth. It can be reduced compared to the embodiment. Other configurations and operations are the same as in the ninth embodiment.

(Eleventh Embodiment) In this embodiment, as shown in FIG. 12, the connection relationship between the voltage dividing resistor Rs and the capacitor C1 is changed from the ninth embodiment shown in FIG. It was done. That is, in the ninth embodiment,
While the voltage dividing resistor Rs is connected in parallel with the capacitor C1, in this embodiment, the voltage dividing resistor Rs is connected to the diode D2.
And a capacitor C1 in parallel. In other words, the relationship between this embodiment and the ninth embodiment is
This is the same as the relationship between the seventh embodiment and the fifth embodiment.

Therefore, in the configuration of the present embodiment, the ninth
Similarly to the embodiment, if the resistance value of the voltage dividing resistor Rs is appropriately set, the voltage across the capacitor C1 is set to the normal operation while the oscillation of the inverter circuit INV is stopped by the operation of the Emiless detection circuit EL. Can be prevented. Other configurations and operations are the same as in the ninth embodiment.

(Twelfth Embodiment) As shown in FIG. 13, the twelfth embodiment differs from the ninth embodiment shown in FIG. 10 in the connection position of the voltage dividing resistor Rs. .
That is, in the ninth embodiment, the voltage dividing resistor Rs is connected in parallel to the capacitor C1, whereas in the present embodiment, the voltage dividing resistor Rs is connected in parallel to the switching element Q1. In other words, the relationship between this embodiment and the ninth embodiment is the same as the relationship between the eighth embodiment and the fifth embodiment.

According to the configuration of this embodiment, when the Emiless detection circuit EL operates and the switching element Q2 is turned off, one of the load circuit Z and the feedback transformer DT1 is turned off.
Since the DC impedance of the secondary winding may be regarded as substantially zero, the state in which the voltage dividing resistor Rs is connected in parallel to the switching element Q1 is substantially equivalent to the state in which the voltage dividing resistor Rs is connected in parallel to the capacitor C1. As a result, also in the present embodiment, similarly to the ninth embodiment, the voltage dividing resistor Rs
By appropriately setting the resistance values of the above, it is possible to prevent the voltage across the capacitor C1 from becoming higher than during normal operation while the oscillation of the inverter circuit INV is stopped by the operation of the Emiless detection circuit EL. Other configurations and operations are the same as in the ninth embodiment.

(Thirteenth Embodiment) This embodiment is different from the conventional configuration shown in FIG.
When the inverter circuit INV is temporarily stopped by the above operation and restarted, the preheating circuit PH performs the preheating operation from the middle instead of from the beginning, so that the primary winding of the feedback transformer DT1 is connected. It is intended to eliminate the difficulty of restarting due to a shortage of flowing current.
That is, when the inverter circuit INV is performing intermittent oscillation, the temperature of the hot cathode (filament) is relatively high, and it is considered that it is not necessary to perform the preheating operation from the beginning.
Therefore, in the present embodiment, the on-period of the switching element Q2 at the start of oscillation of the inverter circuit INV is made longer than that at power-on at the time of restart, and the feedback transformer DT1 is turned on.
The restart is facilitated by supplying a sufficient current to the primary winding.

In the conventional configuration shown in FIG. 25, during the operation of the Emiless detection circuit EL, the capacitor Ct of the preheating circuit PH is not discharged until the capacitor C5 in the Emiless detection circuit EL is discharged and the inverter circuit INV is restarted.
While the resistor R9 is set so as to completely discharge one charge, in the present embodiment, the above-described operation is realized by increasing the resistance value of the resistor R9 as compared with the conventional configuration. That is, by setting the resistor R9 to be larger than the conventional configuration, even if the charge of the capacitor C5 is discharged and the stop state of the inverter circuit INV by the Emiless detection circuit EL is released, the charge remains in the capacitor Ct1. . In short, the configuration of the present embodiment is shown in FIG.
5 is a circuit equivalent to the circuit shown in FIG. 5, in which the discharge resistor Rd is omitted from the first embodiment shown in FIG. 1, or the voltage dividing resistor Rs is used in the fourth embodiment shown in FIG. This is a circuit equivalent to the deleted configuration. According to this configuration, when the inverter circuit INV restarts, the capacitor C
Since the charge at t1 remains, the period forcibly shortened by the preheating circuit PH in the ON period of the switching element Q2 is reduced, and as a result, the ON period of the switching element Q2 when the inverter circuit INV is restarted is reduced. It can be longer than when power is turned on.

The operation of the present embodiment is as shown in FIG.
FIG. 14A shows a voltage between both ends of the capacitor C5.
Flows from the capacitor C5 to the capacitor C5, the voltage across the capacitor C5 rises, and the Zener diode ZD
1 breakover voltage VZD1. At this time, the transistors Q3 and Q4 are turned on, and FIG.
As shown in (c), the oscillation of the inverter circuit INV stops, so that the voltage across the capacitor C5 gradually decreases.
Here, when the transistors Q3 and Q4 are turned on, the capacitor Ct1 of the preheating circuit PH is discharged through the resistor R9, but as shown in FIG.
The voltage at both ends of 1 is not set to 0 V during the stop period of the inverter circuit INV.

As shown in FIG. 14 (a), at time t1, the voltage across capacitor C5 decreases and transistor Q
When the on state of Q3 and Q4 cannot be maintained, FIG.
As shown in (c), the inverter circuit INV is activated, and the preheating circuit PH is also activated. At this point, the off-period of the switching element Q2 is relatively short since the voltage across the capacitor Ct1 is not 0 V as shown in FIG.
As shown in (c), the output of the inverter circuit INV is restarted from a relatively large state. If the Emiless state continues, as shown in FIG.
Of the inverter circuit INV
Stops again. Thus, the inverter circuit INV repeats the oscillation and the stop, and as a result, the discharge lamp FL blinks.

As can be seen by comparing FIG. 14 showing the operation of the present embodiment with FIG. 23 showing the operation of the conventional configuration, at the time t1 when the capacitor C5 is discharged and the inverter circuit INV is restarted in the present embodiment. , Capacitor Ct
1, a sufficient charge is left, and as a result, a sufficiently large current can flow through the feedback transformer DT1 at the time of restart. As a result, restart is easier than in the conventional configuration. Other configurations and operations are shown in FIG.
Is similar to the conventional configuration shown in FIG.

(Fourteenth Embodiment) This embodiment is different from the configuration of the thirteenth embodiment in that an inductor Lf is connected to the AC input terminal of the rectifier DB and the rectifier DB is different from that of the thirteenth embodiment, as shown in FIG. Between the DC output terminals of
, A diode D11 is inserted between the DC output terminal of one (positive electrode) of the rectifier DB and the diode D2, and an anode is connected to a connection point between the diode D11 and the capacitor C1 to connect the switching element Q1 and the smoothing capacitor C1.
In this configuration, a diode D2 having a cathode connected to the connection point 1 is added, and a capacitor C6 is connected in parallel to the diode D2. The capacitor Cf and the inductor Lf form a filter circuit, and the filter circuit removes high-frequency components from an input current from the AC power supply Vin to the rectifier DB. In other words, the filter circuit prevents the leakage of the high-frequency current from the inverter circuit INV to the AC power supply Vin. The diode D11 is connected to the capacitor Cf for the filter circuit by the inverter circuit INV.
Are provided so as not to affect the resonance operation of. The relationship between the configuration of the present embodiment and the thirteenth embodiment is the same as that of the fourth embodiment shown in FIG. 5 and the fifth embodiment shown in FIG.
This is the same as the relationship with the embodiment. The operation by the diode D2 and the capacitor C6 is the same as that of the conventional configuration shown in FIG.

In this embodiment, as in the thirteenth embodiment, when the oscillation of the inverter circuit INV is stopped by the operation of the Emiless detection circuit EL, the capacitor C5 is discharged and the inverter circuit INV is restarted. Since the resistor R9 is set so that the electric charge of the capacitor Ct1 is not completely discharged, the restart is facilitated by the same operation as in the thirteenth embodiment. Other configurations and operations are the same as those of the thirteenth embodiment.

(Fifteenth Embodiment) As shown in FIG. 16, this embodiment differs from the fourteenth embodiment shown in FIG. 15 in that the connection position of the cathode of the diode D1 is changed. . That is, while the cathode of the diode D1 is connected to the connection point between the load circuit Z and the primary winding of the feedback transformer DT1 in the fourteenth embodiment, the capacitor C1 and the load circuit It is connected to the connection point with Z. In this embodiment, the inductor L1 connected in series to the smoothing capacitor C0 is omitted. This configuration is a modification similar to the modification of the third embodiment with respect to the first embodiment.
1, the inductance of the output transformer LT1 and the feedback transformer DT1 provided in the load circuit Z is used. By adopting the configuration of the present embodiment, the inductor L
1 can be reduced, and the number of parts can be reduced as compared with the fourteenth embodiment. Other configurations and operations are the same as those of the fourteenth embodiment.

Sixteenth Embodiment In each of the above-described embodiments, the oscillation of the inverter circuit INV is temporarily stopped and then restarted during the operation of the Emiless detection circuit EL, so that the inverter circuit INV operates intermittently. In this embodiment, the Emiless detection circuit E
At the time of the operation of L, the output of the inverter circuit INV is lowered instead of stopping the oscillation of the inverter circuit INV. Therefore, during the operation of the Emiless detection circuit EL, the inverter circuit INV alternates between the normal output and the low output alternately.

More specifically, in the present embodiment, as shown in FIG. 17, in the conventional configuration shown in FIG.
The Hp capacitor Ct1 is connected to a pnp transistor Q1.
In this configuration, a series circuit of a collector / emitter 0 and a resistor R16 is connected in parallel, one end of a resistor R9 is connected to the base of the transistor Q10, and a diode D7 is omitted. That is, in the conventional configuration shown in FIG.
Is directly connected to one end of the capacitor Ct1, whereas in the present embodiment, one end of the resistor R9 is connected to one end of the capacitor Ct1 via the base / emitter of the transistor Q10 and the resistor R16. It is.

According to this configuration, since the diode D7 is not provided, the transistor Q6 of the preheating circuit PH does not turn on during the operation of the Emiless detection circuit EL, and the inverter circuit INV does not stop. The operation of the Emiless detection circuit EL causes the transistor Q
When 10 is turned on, the voltage across the capacitor Ct1 decreases to a voltage determined by a voltage dividing circuit including the resistor R16 (including the resistors R7 to R9 in addition to the resistor R16), and the voltage across the capacitor Ct1 becomes 0V. No. That is, during the operation of the Emiless detection circuit EL, the ON period of the switching element Q2 is shorter than in the normal operation, but longer than immediately after the power is turned on. Thus, during the operation of the Emiless detection circuit EL, the output of the inverter circuit INV is lower than in the normal operation, and the operation continues. When the capacitor C5 of the Emiless detection circuit EL is discharged and the transistors Q3 and Q4 are turned off, the transistor Q10 is also turned off, and the voltage across the capacitor Ct1 rises, and the operation shifts to the normal operation.

The operation of this embodiment is as shown in FIG.
FIG. 18A shows the voltage between both ends of the capacitor C5.
Flows from the capacitor C5 to the capacitor C5, the voltage across the capacitor C5 rises, and the Zener diode ZD
1 breakover voltage VZD1. At this time, the transistors Q3 and Q4 are turned on, and FIG.
As shown in (c), although the inverter circuit INV continues to oscillate, the output becomes lower than during normal operation. Thus, the voltage across the capacitor C5 gradually decreases. Here, when the transistors Q3 and Q4 are turned on, the voltage across the capacitor Ct1 of the preheating circuit PH decreases to a voltage determined by the voltage dividing circuit including the resistor R16 as shown in FIG.

As shown in FIG. 18A, at time t1, the voltage across capacitor C5 decreases and transistor Q
When the ON state of Q3 and Q4 cannot be maintained, FIG.
As shown in (c), the output of the inverter circuit INV increases again. At this point, the off-period of the switching element Q2 is relatively short since the voltage across the capacitor Ct1 is not 0 V as shown in FIG. 18B, and the output of the inverter circuit INV is relatively large as shown in FIG. 18C. Will increase. If the Emiless state continues, the voltage across the capacitor C5 rises again as shown in FIG. 18A, and the output of the inverter circuit INV becomes low again. As described above, the inverter circuit INV alternately repeats the normal operation and the low output operation, and changes the power supplied to the load circuit Z. That is, Emiless can be notified by changing the brightness of the discharge lamp FL included in the load circuit Z.

As can be seen from a comparison between FIG. 16 showing the operation of the present embodiment and FIG. 23 showing the operation of the conventional configuration, in the present embodiment, the oscillation of the inverter circuit INV at time t0 when the Emiless detection circuit EL operates. At time t1 when the capacitor C5 is discharged without stopping, electric charge remains in the capacitor Ct1, and a sufficiently large current can flow to the feedback transformer DT1. As a result, the restart problem does not occur as compared with the conventional configuration, and the circuit stress can be reduced by reducing the output in the Emiless state.

(Seventeenth Embodiment) This embodiment differs from the configuration of the sixteenth embodiment shown in FIG. 17 in that an inductor Lf is connected to the AC input terminal of the rectifier DB as shown in FIG. Connected, a capacitor Cf is connected between the DC output terminals of the rectifier DB, a diode D11 is inserted between one (positive) DC output terminal of the rectifier DB and the diode D2, and a connection between the diode D11 and the capacitor C1. A diode D2 having an anode connected to a point and a cathode connected to a connection point between the switching element Q1 and the smoothing capacitor C1 is added, and a capacitor C6 is connected in parallel to the diode D2. Capacitor Cf
And the inductor Lf form a filter circuit, which removes high frequency components from the input current from the AC power supply Vin to the rectifier DB. In other words, the filter circuit converts the AC power supply V from the inverter circuit INV.
Prevents the leakage of high-frequency current to in. The diode D11 is provided to separate the filter circuit capacitor Cf so as not to affect the resonance operation of the inverter circuit INV. The relationship between the configuration of this embodiment and the sixteenth embodiment is the same as that of the fourth embodiment shown in FIG.
This is the same as the relationship with the fifth embodiment shown in FIG. The operation by the diode D2 and the capacitor C6 is as follows.
This is the same as the conventional configuration shown in FIG.

In this embodiment, as in the sixteenth embodiment, when the Emiless detection circuit EL operates, the inverter circuit INV continues to oscillate but has a low output. Further, when the capacitor C5 is discharged and the output of the inverter circuit INV increases again, the resistor R16 and the transistor Q10 are provided so that the voltage across the capacitor Ct1 does not become 0V. Other configurations and operations are the same as those of the thirteenth embodiment.

(Eighteenth Embodiment) This embodiment is different from the seventeenth embodiment shown in FIG. 19 in that the connection position of the cathode of the diode D1 is changed as shown in FIG. . That is, the cathode of the diode D1 is connected to the connection point between the load circuit Z and the primary winding of the feedback transformer DT1 in the seventeenth embodiment, whereas the capacitor C1 and the load circuit are connected in the present embodiment. It is connected to the connection point with Z. In this embodiment, the inductor L1 connected in series to the smoothing capacitor C0 is omitted. This configuration is a modification similar to the modification of the third embodiment with respect to the first embodiment.
1, the inductance of the output transformer LT1 and the feedback transformer DT1 provided in the load circuit Z is used. By adopting the configuration of the present embodiment, the inductor L
1 can be reduced, and the number of parts can be reduced as compared with the seventeenth embodiment. Other configurations and operations are the same as those of the seventeenth embodiment.

In each of the above-described embodiments, the configuration of the load circuit Z may be any configuration other than the conventional configuration, as long as it is a load circuit including a resonance circuit. In the circuit configuration including the discharge lamp FL, the number of discharge lamps FL is not limited to one.

[0102]

According to the first aspect of the present invention, there is provided a rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier for supplying output power to a load circuit, and a function for limiting the output power of the inverter circuit. An abnormality detection circuit that controls the other control circuit so as to temporarily stop the operation of the inverter circuit when the abnormality of the load circuit is detected, and then controls the other control circuit to return to the output power during normal operation. Wherein an inverter circuit is connected between the output terminals of the rectifiers and is a series circuit of two switching elements that are alternately turned on and off; and a feedback transformer that alternately turns on and off the switching elements by feeding back part of the output power. And a series circuit of a load circuit and a primary winding of a feedback transformer is connected between one of the DC output terminals of the rectifier and a connection point of both switching elements. An inverter circuit, comprising a series capacitor of a switching capacitor, an inductance element, and a primary winding of a feedback transformer connected between the output terminals of the rectifier and partially smoothing the output voltage of the rectifier. And a discharge impedance element for discharging the electric charge of the smoothing capacitor when the operation is stopped. Since the smoothing capacitor is discharged when the inverter circuit is stopped due to the operation of the abnormality detection circuit, the primary winding of the feedback transformer is required when the operation is restarted. By passing a sufficiently large current through the line through the smoothing capacitor, the startability of the inverter circuit can be improved. As a result, the restart at the time of the intermittent operation becomes easy.

The invention according to claim 2 has a rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier for supplying output power to a load circuit, and a function for limiting the output power of the inverter circuit. Control circuit and an abnormality detection circuit that controls the other control circuit so as to temporarily stop the operation of the inverter circuit when the abnormality of the load circuit is detected, and then controls the other control circuit to return to the output power during normal operation. An inverter circuit connected between the output terminals of the rectifier, and a series circuit of two switching elements that are alternately turned on and off; a feedback transformer that alternately turns on and off the switching elements by feeding back part of the output power; A DC circuit in which a series circuit of a load circuit and a primary winding of a feedback transformer is connected between one of the DC output terminals of the rectifier and a connection point of both switching elements. And a series circuit of one of the switching element, the inductance element, and the primary winding of the feedback transformer are connected between the output terminals of the rectifier, and a series circuit of the inductance element and the primary winding of the feedback transformer is formed. A smoothing capacitor connected between both ends of the other switching element for partially smoothing the output voltage of the rectifier, and one end on the rectifier side in a series circuit of a load circuit, a primary winding of a feedback transformer, and a DC cut capacitor, and both switching circuits; A diode inserted between the series circuit of elements with a polarity to flow charging current from the rectifier to the smoothing capacitor, and an impedance element for power factor improvement connected in parallel with the diode, and the smoothing capacitor is provided when the inverter circuit is stopped. It has a discharge impedance element for discharging the electric charge of Operation since discharging the smoothing capacitor when stopping the inverter circuit according to the, at the time of restart flowed sufficiently large current through the smoothing capacitor to the primary winding of the feedback transformer, it is possible to improve the starting performance of the inverter circuit. As a result, the restart at the time of the intermittent operation becomes easy. In addition, since the impedance element for improving the power factor is provided, the idle period of the input current from the AC power supply to the rectifier is reduced, and the high frequency distortion is reduced only by using a relatively simple high frequency blocking filter circuit. A high power factor can be obtained by making the input current substantially proportional to the absolute value of the input voltage from the AC power supply.

According to a third aspect of the present invention, in the first or second aspect of the present invention, since the inductance element is an inductor, it is easy to design the inductance element according to a target specification. The invention is claimed in claim 1
Alternatively, in the invention of claim 2, since the inductance element is an inductance component included in the load circuit, the number of components is reduced.

According to a fifth aspect of the present invention, there is provided a rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier for supplying output power to a load circuit, and a function for limiting the output power of the inverter circuit. Control circuit and an abnormality detection circuit that controls the other control circuit so as to temporarily stop the operation of the inverter circuit when an abnormality of the load circuit is detected, and then controls the other control circuit to return to the output power during normal operation. An inverter circuit connected between the output terminals of the rectifier, and a series circuit of two switching elements that are alternately turned on and off; a feedback transformer that alternately turns on and off the switching elements by feeding back part of the output power; A DC circuit in which a series circuit of a load circuit and a primary winding of a feedback transformer is connected between one of the DC output terminals of the rectifier and a connection point of both switching elements. And a smoothing capacitor for connecting a series circuit of one switching element, an inductance element and a primary winding of a feedback transformer between output terminals of the rectifier to partially smooth an output voltage of the rectifier, and the one switching element A DC impedance element connected in parallel with the DC impedance, and a voltage dividing impedance element for forming a voltage dividing circuit together with the DC impedance and suppressing a rise in voltage across the DC cut capacitor when the inverter circuit is stopped is added. Since the rise in the voltage across the DC cut capacitor is suppressed when the inverter circuit is stopped due to the operation of the abnormality detection circuit, it is sufficient to pass the DC cut capacitor through the primary winding of the feedback transformer when restarting. A large current can flow, and the startability of the inverter circuit can be improved. As a result, the restart at the time of the intermittent operation becomes easy.

According to a sixth aspect of the present invention, there is provided a rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier for supplying output power to a load circuit, and a function for limiting the output power of the inverter circuit. Control circuit and an abnormality detection circuit that controls the other control circuit so as to temporarily stop the operation of the inverter circuit when an abnormality of the load circuit is detected, and then controls the other control circuit to return to the output power during normal operation. An inverter circuit connected between the output terminals of the rectifier, and a series circuit of two switching elements that are alternately turned on and off; a feedback transformer that alternately turns on and off the switching elements by feeding back part of the output power; A DC circuit in which a series circuit of a load circuit and a primary winding of a feedback transformer is connected between one of the DC output terminals of the rectifier and a connection point of both switching elements. And a series circuit of one of the switching element, the inductance element, and the primary winding of the feedback transformer are connected between the output terminals of the rectifier, and a series circuit of the inductance element and the primary winding of the feedback transformer is formed. A smoothing capacitor connected between both ends of the other switching element for partially smoothing the output voltage of the rectifier, and one end on the rectifier side in a series circuit of a load circuit, a primary winding of a feedback transformer, and a DC cut capacitor, and both switching circuits; A diode inserted between the rectifier and the series circuit of the element with a polarity for flowing a charging current from the rectifier to the smoothing capacitor, an impedance element for power factor improvement connected in parallel to the diode, and connected in parallel to the one switching element. And a DC impedance element. A voltage dividing impedance element that suppresses an increase in the voltage across the DC cut capacitor when the inverter circuit is stopped, and a voltage across the DC cut capacitor when the inverter circuit is stopped due to the operation of the abnormality detection circuit. Is suppressed, a sufficiently large current flows through the primary winding of the feedback transformer through the DC cut capacitor at the time of restart, and the startability of the inverter circuit can be improved. As a result, the restart at the time of the intermittent operation becomes easy. In addition, since the impedance element for improving the power factor is provided, the idle period of the input current from the AC power supply to the rectifier is reduced, and the high frequency distortion is reduced only by using a relatively simple high frequency blocking filter circuit. A high power factor can be obtained by making the input current substantially proportional to the absolute value of the input voltage from the AC power supply.

According to a seventh aspect of the present invention, in the fifth or sixth aspect, since the inductance element is an inductor, it is easy to design the inductance element according to a target specification. The invention is claimed in claim 5
Alternatively, in the invention according to claim 6, since the inductance element is an inductance component included in the load circuit, the number of components is reduced.

According to a ninth aspect of the present invention, there is provided a rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier for supplying output power to a load circuit, and a function for limiting the output power of the inverter circuit. Control circuit and an abnormality detection circuit that controls the other control circuit so as to temporarily stop the operation of the inverter circuit when an abnormality of the load circuit is detected, and then controls the other control circuit to return to the output power during normal operation. An inverter circuit connected between the output terminals of the rectifier, and a series circuit of two switching elements that are alternately turned on and off; a feedback transformer that alternately turns on and off the switching elements by feeding back part of the output power; A DC circuit in which a series circuit of a load circuit and a primary winding of a feedback transformer is connected between one of the DC output terminals of the rectifier and a connection point of both switching elements. And a smoothing capacitor in which a series circuit of one of the switching element, the inductance element and the primary winding of the feedback transformer is connected between the output terminals of the rectifier and partially smoothes the output voltage of the rectifier. However, it has a function of shortening the on-time of the switching element as compared with the normal operation, and has a separate capacitor connected in such a manner that the on-time of the switching element becomes longer as the voltage between both ends is higher. When the output power of the inverter circuit is restored, the voltage across the other control capacitor is set higher than immediately after the power is turned on.When the inverter circuit restarts after the operation of the inverter circuit is stopped by the operation of the abnormality detection circuit, The circuit is restarted with a relatively high output, and a sufficiently large current flows through the primary winding of the feedback transformer. , It is possible to improve the starting performance of the inverter circuit. As a result, the restart at the time of the intermittent operation becomes easy.

A rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier for supplying output power to a load circuit, and a function for limiting the output power of the inverter circuit. Control circuit and an abnormality detection circuit that controls the other control circuit so as to temporarily stop the operation of the inverter circuit when an abnormality of the load circuit is detected, and then controls the other control circuit to return to the output power during normal operation. An inverter circuit connected between the output terminals of the rectifier, and a series circuit of two switching elements that are alternately turned on and off; a feedback transformer that alternately turns on and off the switching elements by feeding back part of the output power; A series circuit consisting of a load circuit and a primary winding of a feedback transformer is connected between one of the DC output terminals of the rectifier and a connection point between the two switching elements. And a series circuit of a switching capacitor, an inductance element and a primary winding of a feedback transformer connected between an output terminal of the rectifier and a series circuit of an inductance element and a primary winding of the feedback transformer. Is connected between both ends of the other switching element, and a smoothing capacitor for partially smoothing the output voltage of the rectifier, and one end on the rectifier side in a series circuit of a load circuit, a primary winding of a feedback transformer, and a DC cut capacitor. A diode inserted with a polarity to flow a charging current from the rectifier to the smoothing capacitor between the series circuit of the switching elements,
A power factor improving impedance element connected in parallel with the diode, and the other control circuit has a function of shortening the on time of the switching element compared with the normal operation. The capacitor is connected in such a way as to increase the output voltage of the inverter circuit when the abnormality detection circuit restores the output power of the inverter circuit. At the time of restart after the operation of the inverter circuit is stopped due to the operation of the abnormality detection circuit, the inverter circuit is restarted with a relatively high output state, and a sufficiently large current flows through the primary winding of the feedback transformer. In addition, the startability of the inverter circuit can be improved. As a result, the restart at the time of the intermittent operation becomes easy. In addition, since the impedance element for improving the power factor is provided, the idle period of the input current from the AC power supply to the rectifier is reduced, and the high frequency distortion is reduced only by using a relatively simple high frequency blocking filter circuit. It is possible,
Also, a high power factor can be obtained by making the input current substantially proportional to the absolute value of the input voltage from the AC power supply.

According to a twelfth aspect of the present invention, in the ninth or tenth aspect of the present invention, since the inductance element is an inductor, it is easy to design the inductance element according to a target specification. According to the invention of claim 9 or claim 10, since the inductance element is an inductance component included in the load circuit, the number of components is reduced.

According to a thirteenth aspect of the present invention, there is provided a rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier for supplying output power to a load circuit, and a function for limiting the output power of the inverter circuit. And an abnormality detection circuit that controls the other control circuit so as to temporarily reduce the output power of the inverter circuit when the abnormality of the load circuit is detected, and then controls the other control circuit to return to the output power during normal operation. A series circuit of two switching elements connected between the output terminals of the rectifier and alternately turned on and off, and a feedback transformer for alternately turning on and off the switching elements by feeding back part of the output power. A series circuit of the load circuit and the primary winding of the feedback transformer is connected between one of the DC output terminals of the rectifier and the connection point of both switching elements. A series circuit of one of a switching element, an inductance element, and a primary winding of a feedback transformer is connected between an output terminal of the rectifier and a smoothing capacitor for partially smoothing an output voltage of the rectifier; The circuit has a function of shortening the on-time of the switching element as compared with the time of normal operation, and further includes a bypass capacitor connected to increase the on-time of the switching element as the voltage between both ends is higher, and includes an abnormality detection circuit. When the output power of the inverter circuit is restored, the voltage across the other control capacitor is set higher than immediately after the power is turned on. Even if the abnormality detection circuit operates, the inverter circuit only lowers the output. Thus, the circuit stress of the inverter circuit can be reduced without stopping the operation. In addition, when the inverter circuit returns to normal operation, the inverter circuit is restarted at a relatively high output state, so that a sufficiently large current flows through the primary winding of the feedback transformer, and the startability of the inverter circuit is reduced. Can be increased. As a result, the restart at the time of the intermittent operation becomes easy.

According to a fourteenth aspect of the present invention, there is provided a rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier for supplying output power to a load circuit, and a function for limiting the output power of the inverter circuit. And an abnormality detection circuit that controls the other control circuit so as to temporarily reduce the output power of the inverter circuit when the abnormality of the load circuit is detected, and then controls the other control circuit to return to the output power during normal operation. A series circuit of two switching elements connected between the output terminals of the rectifier and alternately turned on and off, and a feedback transformer for turning on and off the switching elements alternately by feeding back part of the output power. A DC circuit in which a series circuit of a load circuit and a primary winding of a feedback transformer is connected between one of the DC output terminals of the rectifier and a connection point of both switching elements. Tsu and capacitor preparative, of one switching element and an inductance element and a feedback transformer 1
A series circuit with the secondary winding is connected between the output terminals of the rectifier, and a series circuit with the inductance element and the primary winding of the feedback transformer is connected between both ends of the other switching element to partially smooth the output voltage of the rectifier. A smoothing capacitor,
A rectifier is inserted between one end on the rectifier side and a series circuit of both switching elements in a series circuit of a load circuit, a primary winding of a feedback transformer, and a DC cut capacitor with a polarity for flowing a charging current from the rectifier to the smoothing capacitor. A diode and a power factor improving impedance element connected in parallel with the diode, and the other control circuit has a function of shortening the on-time of the switching element as compared with the normal operation. Equipped with another capacitor connected to extend the on-time of the element, and set the voltage across the other capacitor higher than immediately after power-on when the abnormality detection circuit restores the output power of the inverter circuit. Even if the abnormality detection circuit operates, the inverter circuit only stops the output and stops the operation. It can be without, to reduce the circuit stress of the inverter circuit. In addition, when the inverter circuit returns to normal operation, the inverter circuit is restarted at a relatively high output state, so that a sufficiently large current flows through the primary winding of the feedback transformer, and the startability of the inverter circuit is reduced. Can be increased. As a result, the restart at the time of the intermittent operation becomes easy. In addition, since the impedance element for improving the power factor is provided, the idle period of the input current from the AC power supply to the rectifier is reduced, and the high frequency distortion is reduced only by using a relatively simple high frequency blocking filter circuit. A high power factor can be obtained by making the input current substantially proportional to the absolute value of the input voltage from the AC power supply.

According to a fifteenth aspect of the present invention, in the thirteenth or fourteenth aspect, since the inductance element is an inductor, it is easy to design the inductance element according to a target specification. The invention is
In the invention according to claim 13 or 14, since the inductance element is an inductance component included in the load circuit, the number of components is reduced.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention.

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

FIG. 3 is a circuit diagram showing a second embodiment of the present invention.

FIG. 4 is a circuit diagram showing a third embodiment of the present invention.

FIG. 5 is a circuit diagram showing a fourth embodiment of the present invention.

FIG. 6 is a circuit diagram showing a fifth embodiment of the present invention.

FIG. 7 is a circuit diagram showing a sixth embodiment of the present invention.

FIG. 8 is a circuit diagram showing a seventh embodiment of the present invention.

FIG. 9 is a circuit diagram showing an eighth embodiment of the present invention.

FIG. 10 is a circuit diagram showing a ninth embodiment of the present invention.

FIG. 11 is a circuit diagram showing a tenth embodiment of the present invention.

FIG. 12 is a circuit diagram showing an eleventh embodiment of the present invention.

FIG. 13 is a circuit diagram showing a twelfth embodiment of the present invention.

FIG. 14 is an operation explanatory diagram of the thirteenth embodiment of the present invention.

FIG. 15 is a circuit diagram showing a fourteenth embodiment of the present invention.

FIG. 16 is a circuit diagram showing a fifteenth embodiment of the present invention.

FIG. 17 is a circuit diagram showing a sixteenth embodiment of the present invention.

FIG. 18 is an operation explanatory view of the above.

FIG. 19 is a circuit diagram showing a seventeenth embodiment of the present invention.

FIG. 20 is a circuit diagram showing an eighteenth embodiment of the present invention.

FIG. 21 is a circuit diagram showing a conventional example.

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

FIG. 23 is an explanatory diagram of the operation of the above.

FIG. 24 is a circuit diagram showing another conventional example.

FIG. 25 is a circuit diagram showing still another conventional example.

FIG. 26 is a circuit diagram showing another conventional example.

[Explanation of symbols]

 C0 Smoothing capacitor C1 Capacitor (for DC cut) C6 Capacitor Ct1 (Capacitor for other control) D2 Diode DB Rectifier DT1 Feedback transformer EL Emiless detection circuit INV Inverter circuit L1 Inductor LT1 Output transformer PH Preheating circuit Q1, Q2 Switching element R14, R15 Resistance Rd Discharge resistance Rs Voltage dividing resistance Vin AC power supply Z Load circuit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshinobu Murakami 1048 Okadoma Kadoma, Kadoma-shi, Osaka Matsushita Electric Works, Ltd. (72) Inventor Joji Oyama 1048 Okadoma Kadoma, Kadoma-shi, Osaka Matsushita Electric Works ( 72) Inventor Shigeru Well 1048 Kadoma, Kazuma, Osaka Prefecture F-term in Matsushita Electric Works, Ltd.

Claims (16)

[Claims] 1. A rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier and supplying output power to a load circuit, a remote control circuit having a function of limiting the output power of the inverter circuit, and a load. An abnormality detection circuit that controls the other control circuit so as to temporarily stop the operation of the inverter circuit when the abnormality of the circuit is detected, and then controls the other control circuit so as to return to the output power during normal operation. A series circuit of two switching elements connected between output terminals of a rectifier and alternately turned on and off, a feedback transformer for alternately turning on and off the switching elements by feeding back part of output power, a load circuit and a feedback transformer. A series circuit with the primary winding of the rectifier is connected between one of the DC output terminals of the rectifier and the connection point of the two switching elements, and A series circuit of one of the switching element, the inductance element, and the primary winding of the feedback transformer is connected between the output terminals of the rectifier; and a smoothing capacitor for partially smoothing the output voltage of the rectifier is provided. A power supply device further comprising a discharge impedance element for discharging the electric charge of the power supply. 2. A rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier and supplying output power to a load circuit, a control circuit having a function of limiting the output power of the inverter circuit, and a load. An abnormality detection circuit that controls the other control circuit so as to temporarily stop the operation of the inverter circuit when the abnormality of the circuit is detected, and then controls the other control circuit so as to return to the output power during normal operation. A series circuit of two switching elements connected between output terminals of a rectifier and alternately turned on and off, a feedback transformer for alternately turning on and off the switching elements by feeding back part of output power, a load circuit and a feedback transformer. A series circuit with the primary winding of the rectifier is connected between one of the DC output terminals of the rectifier and the connection point of the two switching elements, and A series circuit of one switching element, an inductance element and a primary winding of a feedback transformer is connected between the output terminals of the rectifier, and a series circuit of the inductance element and the primary winding of the feedback transformer is connected to the other switching element. And a series circuit of one end on the rectifier side and both switching elements in a series circuit of a load circuit, a primary winding of a feedback transformer, and a DC cut capacitor connected between both ends of the rectifier. Between the rectifier and the polarity to flow the charging current from the rectifier to the smoothing capacitor, and a power factor improving impedance element connected in parallel to the diode, and discharges the charge of the smoothing capacitor when the inverter circuit is stopped. A power supply device further comprising a discharge impedance element to be discharged. 3. The power supply device according to claim 1, wherein the inductance element is an inductor. 4. The power supply device according to claim 1, wherein the inductance element is an inductance component included in the load circuit. 5. A rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier and supplying output power to a load circuit, a remote control circuit having a function of limiting the output power of the inverter circuit, and a load. An abnormality detection circuit that controls the other control circuit so as to temporarily stop the operation of the inverter circuit when the abnormality of the circuit is detected, and then controls the other control circuit so as to return to the output power during normal operation. A series circuit of two switching elements connected between output terminals of a rectifier and alternately turned on and off, a feedback transformer for alternately turning on and off the switching elements by feeding back part of output power, a load circuit and a feedback transformer A series circuit with the primary winding of the rectifier is connected between one of the DC output terminals of the rectifier and a connection point of the two switching elements, and a capacitor for DC cut is provided. A series circuit of one switching element, an inductance element, and a primary winding of a feedback transformer is connected between the output terminals of the rectifier, and a smoothing capacitor for partially smoothing the output voltage of the rectifier is connected in parallel to the one switching element. A DC impedance element, and a voltage dividing circuit that forms a voltage dividing circuit together with the DC impedance and suppresses a rise in voltage across the DC cut capacitor when the inverter circuit is stopped. Power supply. 6. A rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier for supplying output power to a load circuit, a remote control circuit having a function of limiting output power of the inverter circuit, and a load. An abnormality detection circuit that controls the other control circuit so as to temporarily stop the operation of the inverter circuit when the abnormality of the circuit is detected, and then controls the other control circuit so as to return to the output power during normal operation. A series circuit of two switching elements connected between output terminals of a rectifier and alternately turned on and off, a feedback transformer for alternately turning on and off the switching elements by feeding back part of output power, a load circuit and a feedback transformer. A series circuit with the primary winding of the rectifier is connected between one of the DC output terminals of the rectifier and the connection point of the two switching elements, and A series circuit of one switching element, an inductance element and a primary winding of a feedback transformer is connected between the output terminals of the rectifier, and a series circuit of the inductance element and the primary winding of the feedback transformer is connected to the other switching element. And a series circuit of one end on the rectifier side and both switching elements in a series circuit of a load circuit, a primary winding of a feedback transformer, and a DC cut capacitor connected between both ends of the rectifier. A diode inserted with a polarity to flow a charging current from the rectifier to the smoothing capacitor, a power factor improving impedance element connected in parallel to the diode, and a DC impedance element connected in parallel to the one switching element. When the inverter circuit is stopped, a voltage divider circuit is formed with the DC impedance. Power apparatus characterized by inhibiting voltage-dividing impedance elements an increase in the voltage across the capacitor for flow cut is made is added. 7. The power supply device according to claim 5, wherein the inductance element is an inductor. 8. The power supply device according to claim 5, wherein the inductance element is an inductance component included in the load circuit. 9. A rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier and supplying output power to a load circuit, a remote control circuit having a function of limiting the output power of the inverter circuit, and a load. An abnormality detection circuit that controls the other control circuit so as to temporarily stop the operation of the inverter circuit when the abnormality of the circuit is detected, and then controls the other control circuit so as to return to the output power during normal operation. A series circuit of two switching elements connected between output terminals of a rectifier and alternately turned on and off, a feedback transformer for alternately turning on and off the switching elements by feeding back part of output power, a load circuit and a feedback transformer. A series circuit with the primary winding of the rectifier is connected between one of the DC output terminals of the rectifier and the connection point of the two switching elements, and A series circuit of one of the switching element, the inductance element, and the primary winding of the feedback transformer is connected between the output terminals of the rectifier; and a smoothing capacitor for partially smoothing the output voltage of the rectifier is provided. It has a function of shortening the on-time of the normal operation, and has another capacitor connected so that the on-time of the switching element becomes longer as the voltage between both ends is higher. A power supply device characterized in that the voltage across the other control capacitor at the time when power is restored is set higher than immediately after power-on. 10. A rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier and supplying output power to a load circuit, a remote control circuit having a function of limiting the output power of the inverter circuit, and a load. An abnormality detection circuit that controls the other control circuit so as to temporarily stop the operation of the inverter circuit when the abnormality of the circuit is detected, and then controls the other control circuit so as to return to the output power during normal operation. A series circuit of two switching elements connected between output terminals of a rectifier and alternately turned on and off, a feedback transformer for alternately turning on and off the switching elements by feeding back part of output power, a load circuit and a feedback transformer. DC cut capacitor connected in series with the primary winding of the rectifier between one of the DC output terminals of the rectifier and the connection point of both switching elements And a series circuit of one switching element, an inductance element and the primary winding of the feedback transformer is connected between the output terminals of the rectifier, and a series circuit of the inductance element and the primary winding of the feedback transformer is connected to the other switching element. A smoothing capacitor connected between both ends of the element to partially smooth the output voltage of the rectifier, and one end on the rectifier side and a series connection of both switching elements in a series circuit of a load circuit, a primary winding of a feedback transformer, and a DC cut capacitor. A diode inserted between the circuit and the rectifier with a polarity for flowing a charging current from the rectifier to the smoothing capacitor, and an impedance element for power factor improvement connected in parallel to the diode,
The alternate control circuit has a function of shortening the ON time of the switching element as compared with the normal operation, and includes an alternate control capacitor connected to increase the ON time of the switching element as the voltage across both ends is increased, and A power supply device characterized in that the voltage across the other control capacitor is set higher than immediately after power-on when the detection circuit restores the output power of the inverter circuit. 11. The power supply device according to claim 9, wherein the inductance element is an inductor. 12. The power supply device according to claim 9, wherein the inductance element is an inductance component included in the load circuit. 13. A rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier and supplying output power to a load circuit, a control circuit having a function of limiting the output power of the inverter circuit, and a load. An abnormality detection circuit for controlling the control circuit so as to once reduce the output power of the inverter circuit when detecting an abnormality in the circuit, and then controlling the control circuit so as to return to the output power during normal operation; Is a series circuit of two switching elements connected between the output terminals of the rectifier and alternately turned on and off, a feedback transformer for alternately turning on and off the switching elements by feeding back part of the output power, and a load circuit and a feedback circuit. A DC cut capacitor connected in series with the primary winding of the transformer between one of the DC output terminals of the rectifier and the connection point of both switching elements. A series circuit of one of the switching element, the inductance element, and the primary winding of the feedback transformer is connected between the output terminals of the rectifier, and includes a smoothing capacitor for partially smoothing the output voltage of the rectifier. It has a function of shortening the on-time of the switching element compared to the normal operation, and has another capacitor connected so that the on-time of the switching element becomes longer as the voltage between both ends is higher, and the abnormality detection circuit is an inverter circuit. A power supply device, wherein the voltage across the other control capacitor at the time when the output power is restored is set higher than immediately after the power is turned on. 14. A rectifier for rectifying an AC power supply, an inverter circuit connected to an output terminal of the rectifier and supplying output power to a load circuit, a control circuit having a function of limiting the output power of the inverter circuit, and a load. An abnormality detection circuit that controls another control circuit so as to temporarily reduce the output power of the inverter circuit when the circuit abnormality is detected, and then controls the other control circuit to return to the output power during normal operation; Is a series circuit of two switching elements connected between the output terminals of the rectifier and alternately turned on and off, a feedback transformer for alternately turning on and off the switching elements by feeding back part of the output power, and a load circuit and a feedback circuit. A DC cutting capacitor connected in series between the primary winding of the transformer and one of the DC output terminals of the rectifier and the connection point of both switching elements. And a series circuit of one switching element, an inductance element and the primary winding of the feedback transformer is connected between the output terminals of the rectifier, and a series circuit of the inductance element and the primary winding of the feedback transformer is connected to the other. A smoothing capacitor connected between both ends of the switching element for partially smoothing the output voltage of the rectifier, one end on the rectifier side in a series circuit of a load circuit, a primary winding of a feedback transformer, and a capacitor for DC cut-off, and both switching elements; A diode inserted between the series circuit and the rectifier with a polarity that allows the charging current to flow from the rectifier to the smoothing capacitor, and an impedance element connected in parallel with the diode for power factor improvement, and the other control circuit turns on the switching element. It has the function of shortening the time compared to normal operation, and the higher the voltage between both ends, the shorter the on-time of the switching element. It is characterized in that it has another control capacitor connected in a relationship that makes it possible to set the voltage across the other control capacitor higher than immediately after power-on when the abnormality detection circuit restores the output power of the inverter circuit. Power supply. 15. The power supply device according to claim 13, wherein the inductance element is an inductor. 16. The power supply device according to claim 13, wherein the inductance element is an inductance component included in the load circuit.