JP2002176780A - Power supply unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply unit that surely start self-oscillation of an inverter circuit. SOLUTION: The inverter circuit 6 includes a pair of switching elements Q1 and Q2, and switches the output of a direct-current converter 5 by the switching elements Q1 and Q2 to convert the output into alternating-current voltage. The inverter circuit applies the voltage to a resonance load circuit 7. The resonance load circuit 7 is connected in series with the primary winding of a driving transformer DT1, and the switching elements Q1 and Q2 are caused to self-oscillate by the feedback action of the driving transformer DT1. A separately controlling circuit 10 is provided with a capacitor C5 that is charged with direct-current voltage obtained from the output of a direct-current converter 5, and turns off the witching element Q2 when the voltage across the capacitor C5 reaches a specified voltage. The on-width is reduced with increase in supply voltage. A reset circuit 12 zeros the charges in the capacitor C5 when the inverter circuit 6 is started, thereby preventing the switching element Q2 from being forcedly turned off by the separately controlling circuit 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply.

[0002]

2. Description of the Related Art FIG. 19 shows a circuit diagram of a conventional power supply device. This power supply device includes a rectifier circuit 3 such as a diode bridge for full-wave rectifying a power supply voltage of an AC power supply 1 input through a filter circuit 2, and a rectification output of the rectifier circuit 3 input through a filter circuit 4. And a valley-filling power supply circuit (DC conversion circuit) 5 for partially smoothing the output and supplying the same to an inverter circuit 6 described later, 6 is provided.

The inverter circuit 6 includes a filter circuit 4 and high-frequency diodes D1, D2 between output terminals of the rectifier circuit 3.
And a series circuit of a pair of switching elements Q1 and Q2 composed of a field-effect transistor connected via the series circuit of the above. The switching elements Q1 and Q2 are alternately turned on / off by a drive transformer DT1 described later. A primary winding of a driving transformer DT1 for self-excited oscillation is connected to a connection point of the switching elements Q1 and Q2, and the other end of the primary winding of the driving transformer DT1 and diodes D1 and D2.
Is connected to a series circuit of a DC cut capacitor C1 and a resonance load circuit 7. Between the gate and source of the switching elements Q1 and Q2,
Secondary windings provided separately to the driving transformer DT1 corresponding to the respective switching elements Q1 and Q2 are connected via resistors R1 and R2, and according to the current flowing through the primary winding of the driving transformer DT1. A voltage for turning on the switching element Q1 or Q2 is generated in one of the secondary windings. A series circuit of Zener diodes ZD1 and ZD2, whose cathodes are connected to each other, and a series circuit of Zener diodes ZD3 and ZD4 are connected between the gates and sources of the switching elements Q1 and Q2, respectively. The overvoltage is prevented from being applied between the gate and source of Q2. Here, the drive transformer DT1
, Resistors R1 and R2, and Zener diodes ZD1 to ZD1
D4 forms a drive circuit 8.

FIG. 20 shows a specific circuit diagram of the resonance load circuit 7. This resonance load circuit 7 is composed of a leakage transformer having a primary winding connected between a capacitor C1 and a primary winding of a driving transformer DT1. A transformer LT1, discharge lamps La1 and La2 such as fluorescent lamps in which the power supply side terminals of one of the filaments f11 and f22 are connected to both ends of a secondary winding of the transformer LT1, respectively, and both filaments f1
1, a capacitor C connected between the non-power supply terminals of f22
7, the capacitor C7, the leakage inductance of the transformer LT1, and the discharge lamps La1 and La2 constitute a resonance circuit. Here, the secondary winding N of the transformer LT1 is connected to the filaments f11 and f22 of the discharge lamps La1 and La2.
2, a preheating current is supplied via a capacitor C7.
Also, the other filament f1 of the discharge lamps La1 and La2
2, f21, the terminals on the power supply side are connected via a capacitor C8 and an auxiliary winding N3 magnetically coupled to the secondary side of the transformer LT1, the terminals on the non-power supply side are short-circuited, and the auxiliary winding N3 From the filament f1 via the capacitor C8
2, f21 is supplied with a preheating current.

Further, the circuit includes a start circuit 9 for starting the self-excited oscillation of the switching elements Q1 and Q2 when the power is turned on. The starter circuit 9 includes a series circuit of a resistor R4 and a capacitor C4 connected between the output terminals of the rectifier circuit 3 via the filter circuit 4, and a connection point between the resistor R4 and the capacitor C4 and the gate of the switching element Q2. It comprises a connected trigger element TD1 and a series circuit of a diode D4 and a resistor R3 connected between a connection point of the resistor R4 and the capacitor C4 and a connection point of the switching elements Q1 and Q2. The diode D4 is connected in the direction in which current flows from the connection point of the resistor R4 and the capacitor C4 to the connection point of the switching elements Q1 and Q2.

The valley filling power supply circuit 5 includes a switching element Q
Smoothing capacitor C connected in parallel with the series circuit of Q1 and Q2
0, choke choke L1 and discharge diode D5
, A capacitor C3 connected between both ends of the series circuit, a charging diode D3 connected between a connection point of the choke L1 and the diode D5 and a connection point of the resonance load circuit 7 and the drive transformer DT1. It is composed of

That is, in the valley filling power supply circuit 5, when the switching element Q2 is turned on, the rectifier circuit 3-filter circuit 4-diode D1-diode D2 (capacitor C
2) A current flows through a path of -smoothing capacitor C0-choke L1-diode D3 → primary winding of drive transformer DT1-switching element Q2-filter circuit 4-rectifier circuit 3. Next, when the switching element Q2 is turned off, the energy stored in the choke L1 is transferred to the choke L1-diode D3-primary winding of the driving transformer DT1-parasitic diode of the switching element Q1-smoothing capacitor C0-.
It is discharged through the path of the choke L1, and the smoothing capacitor C0 is charged. In this configuration, when the switching element Q2 is turned on, the energy accumulated in the choke L1 charges the smoothing capacitor C0.
Is dropped according to the ratio between the ON period and the OFF period of the switching element Q2. That is, the diode D
3, a parasitic diode of the switching element Q1, the choke L1, the switching element Q2, and the smoothing capacitor C0 constitute a step-down chopper circuit.

Further, this circuit includes a preheating control circuit 11 for adjusting the ON width of the switching element Q2 during preheating and supplying a preheating current to the discharge lamps La1 and La2. The preheating control circuit 11 includes a series circuit of a resistor R9, a diode D9 and capacitors C9 and C10 connected between the gate and the source of the switching element Q2, a resistor R10 connected in parallel to the capacitor C9, a diode D9 and a capacitor. Diode D1 connected in anti-parallel with the series circuit of C9
0, a diode D11 connected in anti-parallel to the capacitor C10, and a base connected to a connection point of the capacitors C9 and C10, and a collector-emitter connection between the gate and source of the switching element Q2 via the diode D7. And a switching element Q5 formed of an NPN transistor connected thereto.

Here, the operation of the present circuit will be briefly described. When the AC power supply 1 is turned on, the starting circuit 9 charges the capacitor C4 via the resistor R4,
4 accumulates electric charges. Then, when the voltage across the capacitor C4 reaches the breakover voltage of the trigger element TD1, the trigger element TD1 conducts, the electric charge accumulated in the capacitor C4 flows into the gate of the switching element Q2, and the switching element Q2 turns on.

Thus, the rectifier circuit 3—filter circuit 4
-Diode D1-Capacitor C1-Resonant load circuit 7-
Primary winding of driving transformer DT1-switching element Q2
-Filter circuit 4-Route of rectifier circuit 3 and rectifier circuit 3-
Filter circuit 4-Diode D1-Diode D2 (capacitor C2) -Smoothing capacitor C0-Choke L1-
A current flows through the diode D3, the primary winding of the driving transformer DT1, the switching element Q2, the filter circuit 4, and the rectifier circuit 3. At this time, the drive transformer DT1 applies an on-direction bias to the switching element Q2 and keeps the switching element Q1 off.
2 is completely on. Thereafter, when the resonance current is reversed by the resonance action of the resonance load circuit 7, the drive transformer DT
1, the switching element Q1 is turned on, the switching element Q2 is turned off, and the switching elements Q1, Q
2 performs a self-excited oscillation operation.

By the way, when the switching elements Q1 and Q2 start the self-excited oscillation operation and a drive signal is applied to the gate of the switching element Q2 by the drive transformer DT1,
Secondary winding of drive transformer DT1-resistor R2-resistor R9-
Diode D9-Capacitor C9-Capacitor C10-
A current flows through the secondary winding path of the drive transformer DT1,
The capacitors C9 and C10 are charged. When the voltage across the capacitor C10 reaches the threshold voltage of the switching element Q5, the switching element Q5 is turned on, and the gate and source of the switching element Q2 are short-circuited via the diode D7 and the switching element Q5.
Since the gate signal of the switching element Q2 is extracted, the switching element Q2 is turned off. At this time, since the ON width of the switching element Q2 is shorter than that during normal lighting, the power supplied to the resonance load circuit 7 is suppressed,
A preheating current can flow through the filaments of the discharge lamps La1 and La2. When the resonance current is inverted, the gate of the switching element Q2 has a negative potential, so that the electric charge accumulated in the capacitor C10 is reduced by the diode D10 and the resistor R10.
2 is discharged. On the other hand, since the diode D9 is connected in series to the capacitor C9, all the charge accumulated in the capacitor C9 is not discharged when the switching element Q2 is turned off, and the capacitor C9 is gradually charged. When the voltage across the capacitor C9 is charged to a voltage substantially equal to the gate voltage of the switching element Q2, the charging current stops flowing to the capacitor C10, so that the switching element Q5 is maintained in the off state, and the preheating period ends. A resistor R10 constituting a discharge path is connected in parallel to the capacitor C9.
Is set to a sufficiently large value, the capacitor C9 is not completely discharged when the switching element Q2 is turned off during the self-excited oscillation operation.

Next, the operation of the main circuit during normal lighting will be briefly described. First, the switching element Q2 is turned on,
When the switching element Q1 is turned off, a current flows through the path of the valley filling power supply circuit 5-capacitor C2-capacitor C1-resonant load circuit 7-primary winding of the driving transformer DT1-switching element Q2-valley filling power supply circuit 5. . Here, when the output voltage of the rectifier circuit 3 is higher than the voltage across the smoothing capacitor C0, the input current is drawn from the AC power supply 1, and the rectifier circuit 3-filter circuit 4-diode D1
-Diode D2-smoothing capacitor C0-choke L1
A triangular charging current (chopper current) flows through a path of the diode D3, the primary winding of the driving transformer DT1, the switching element Q2, the filter circuit 4, and the rectifier circuit 3.
Note that the peak value of the charging current is proportional to the output voltage of the rectifier circuit 3.

Thereafter, when the resonance current is inverted by the resonance operation of the resonance load circuit 7, the drive signal of the drive transformer DT1 is inverted, and the switching element Q2 is turned off. When the switching element Q2 is turned off, a regenerative current flows through the path of the resonance load circuit 7, the primary winding of the driving transformer DT1, the parasitic diode of the switching element Q1, the capacitor C2, the capacitor C1, and the resonance load circuit 7. If a chopper current flows when the switching element Q2 is turned on, the choke L1-diode D3-drive transformer DT
A regenerative current flows through a path of one primary winding, a parasitic diode of the switching element Q1, a smoothing capacitor C0, and a choke L1.

When the drive signal of the drive transformer DT1 is applied to the gate of the switching element Q1, the switching element Q1 is turned on, and the capacitor C1 is used as a power supply to provide a capacitor C1-capacitor C2-switching element Q1-drive transformer DT1. A resonance current flows through the path of the primary winding, the resonance load circuit 7 and the capacitor C1. Here, when the charge stored in the capacitor C2 becomes zero when the switching element Q2 is turned on, the resonance current flowing through the capacitor C2 flows through the diode D2.

Next, when the resonance current is reversed by the resonance operation of the resonance load circuit 7, the switching element Q1 is turned off, and the resonance load circuit 7-capacitor C1-diode D
A regenerative current flows through a path of 2-capacitor C3-parasitic diode of switching element Q2-drive transformer DT1-resonance load circuit 7.

In this circuit, a high-frequency voltage is applied to the transformer LT1 of the resonance load circuit 7 by repeating the above-described series of operations, and the resonance circuit including the leakage inductance of the transformer LT1, the capacitor C7, and the discharge lamps La1, La2 performs the resonance operation. Is performed, and the discharge lamps La1 and La2 are turned on at a high frequency. Also, in a section where the output voltage of the rectifier circuit 3 is higher than the voltage across the smoothing capacitor C0 of the valley filling power supply circuit 5, a chopper current flows from the AC power supply 1, and the inverter circuit 6 also reduces the magnitude of the power supply voltage. Accordingly, a sine wave-shaped input current can be obtained by averaging the high-frequency current proportional to the voltage value of these power supply voltages in the filter circuit 4, thereby reducing input current distortion. Can be improved.

FIG. 21A shows the power supply voltage Vin of the AC power supply 1, FIG. 21B shows the voltage VC3 across the capacitor C3, and FIG. 21C shows the lamp current ILa of the discharge lamps La1 and La2. By the above operation, the voltage VC3 across the capacitor C3 becomes a DC voltage waveform that fills the valley of the rectified output of the rectifier circuit 3 (the absolute value of the power supply voltage Vin of the AC power supply), and the lamp current ILa Has a current waveform in which the current value in the period corresponding to the peak and the valley of the rectified output of the rectifier circuit 3 has increased.

[0018]

In the power supply device having the above-described structure, the amplitude of the lamp current ILa changes between the peak and the valley of the rectified output, and the lamp current ILa increases due to the voltage fluctuation of the AC power supply 1. There is a problem of fluctuation. Therefore, in the power supply device described above, another control circuit for correcting the amplitude of the lamp current ILa at the peak of the rectified output, improving the crest factor of the lamp current ILa, and correcting the fluctuation of the lamp current ILa with respect to the voltage fluctuation. 10 are provided.

The other control circuit 10 includes a series circuit of resistors R5 and R6 connected between both ends of a capacitor C3, a capacitor C6 connected in parallel with the resistor R6, and an emitter-collector connection between both ends of the resistor R6. And a switching element Q4 composed of a PNP transistor whose base is connected to a connection point between the secondary winding of the driving transformer DT1 and the resistor R2 via a series circuit of the resistor R8 and the diode D8.
And a series circuit of a resistor R7 and an on-width setting capacitor (hereinafter referred to as a capacitor) C5 connected in parallel with the resistor R6, a base connected to a connection point of the resistor R7 and the capacitor C5, and a collector A diode D7 is provided between the gate and source of the switching element Q2 between the emitters.
And a switching element Q3 composed of an NPN transistor connected through the switching element Q3. Here, the resistance R5
A DC power supply circuit 10a is composed of R6 and the capacitor C6. The voltage across the capacitor C3 is divided by the resistors R5 and R6, and the DC voltage obtained by smoothing the voltage by the capacitor C6 is used as the operating power supply of the control circuit 10.

Here, the operation of the remote control circuit 10 is shown in FIG.
This will be briefly described with reference to FIGS. FIG.
2 (a) is a drive signal VDT1 applied to the switching element Q2, and FIG.
Source-to-source voltage VQ2gs, FIG.
22 (d) shows the switching element Q
2 shows the drain-source voltage VQ2ds, and FIG. 22E shows the drain current IQ2 of the switching element Q2.

When a voltage is generated in the secondary winding of the drive transformer DT1 in accordance with the resonance current flowing on the primary side of the drive transformer DT1, and a sine-wave drive signal VDT1 is input to the gate of the switching element Q2 (see FIG. 22 (a)), the gate-source voltage V of the switching element Q2
Q2gs is clamped to a predetermined voltage (zener voltage) by zener diodes ZD3 and ZD4 (see FIG. 22B). Here, when the switching element Q2 is on, the cathode of the diode D8 is at a positive potential, so that the switching element Q4 is off.

At this time, the DC power supply circuit 10a connects the resistor R7
Charging current flows through the capacitor C5 via the capacitor C5, and the voltage VC5 across the capacitor C5 gradually increases (FIG. 22 (c)).
When the voltage VC5 across the capacitor C5 reaches the threshold voltage of the switching element Q3, the switching element Q3 is turned on, and the diode D7 and the switching element Q3 are connected between the gate and source of the switching element Q2.
And the switching element Q2 is turned off. Here, the switching element Q4 is
The voltage generated in the secondary winding of T1 is inverted and diode D
In order to maintain the off-state until the cathode of the switching element 8 becomes a negative potential, the voltage across the capacitor C5 is switched to the switching element Q5.
The switching circuit Q2 is maintained in an off state by the control circuit 10 from the time when the switching element Q1 is turned on after exceeding the threshold voltage of No. 3 (that is, FIG. 22).
The period Ta in (d) is the off period. ). Then, the primary current of the driving transformer DT1 is inverted by the resonance operation of the resonance load circuit 7, and the driving signal VDT generated in the secondary winding is generated.
When the polarity of 1 is inverted, the switching element Q4 is turned on, and the charge charged in the capacitor C5 is released via the resistor R7 and the switching element Q4, so that the switching element Q3 is turned off.

Here, when the voltage across the capacitor C3 increases, the time until the voltage across the capacitor C5 reaches the threshold voltage of the switching element Q3 (ie, the time until the drive signal of the switching element Q2 is pulled out). In the remote control circuit 10, the switching time is set so that the ON time of the switching element Q2 is inversely proportional to the magnitude of the output voltage of the power supply circuit 5 (ie, the absolute value of the power supply voltage Vin of the AC power supply 1). The ON width of the element Q2 is modulated. Since the charging time of the capacitor C5 changes according to the capacitance of the capacitor C6 constituting the DC power supply unit 10a, the degree of modulation of the ON width of the switching element Q2 can be adjusted.

In this circuit, when the AC power supply 1 is turned on, a charging current flows from the rectifier circuit 3 to the capacitor C4 via the filter circuit 4 and the resistor R4, and as shown in FIG. When the voltage VC5 reaches the breakover voltage of the trigger element TD1 (see FIG. 23).
At times t1, t2,... In (a), the trigger element TD1 conducts, a voltage is applied to the gate of the switching element Q2, and the switching elements Q1, Q2 start self-excited oscillation. Since the switching element Q4 is in an off state before the oscillation operation of Q1 and Q2 starts, a charging current flows to the capacitor C5 via the resistor R7 by the output of the DC power supply unit 10a, and the voltage across the capacitor C5. Gradually increases (FIG. 23).
(B)). Here, when the voltage VC5 across the capacitor C5 reaches the threshold voltage of the switching element Q3 at time t0 before the trigger signal is input from the starting circuit 9 to the gate of the switching element Q2, the switching element Q3 is turned on. Is turned on, and the diode D7 and the switching element Q3 are connected between the gate and the source of the switching element Q2.
, The trigger signal applied to the gate of the switching element Q2 is pulled out by the switching element Q3, and the switching element Q2 is kept off (see FIG. 23C), and the inverter circuit 6
Oscillation operation could not be started.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a power supply device capable of reliably starting a self-excited oscillation operation of an inverter circuit.

[0026]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a rectifier circuit for rectifying an AC voltage of an AC power supply, and a DC voltage having a smoothing capacitor and smoothing the output of the rectifier circuit. And an inverter circuit having a series circuit of a pair of switching elements that alternately turn on and off, and converting the output of the DC conversion circuit into an AC voltage by switching the output of the pair of switching elements. A resonant load circuit connected between the output terminals of the circuit via a DC cut capacitor, and a primary winding connected to a path through which the resonant current of the resonant load circuit flows, and separately provided at a control end of each switching element. A driving transformer to which the secondary winding is connected, and a starting circuit for starting a switching operation of the pair of switching elements. In a power supply device that self-oscillates the pair of switching elements by a feedback action of a transformer, the power supply apparatus includes an on-width setting capacitor charged by a power supply voltage of a DC power supply. And a reset circuit that sets the charge of the on-width setting capacitor to zero when the inverter circuit starts up, and a reset circuit that sets the time until the voltage across the on-width setting capacitor is charged to a predetermined voltage. Since the reset means sets the charge of the ON width setting capacitor to zero at the time of starting the inverter circuit, the voltage across the ON width setting capacitor is charged to a predetermined voltage at the time of starting. Therefore, it is possible to prevent another control circuit from forcibly turning off one switching element. , It is possible to reliably start the self-excited oscillation operation of the switching element.

According to a second aspect of the present invention, there is provided a rectifier circuit for rectifying an AC voltage of an AC power supply, and a series circuit of a pair of switching elements which are turned on / off alternately, and the DC voltage is switched by the pair of switching elements. An inverter circuit that converts the output of the rectifier circuit into an AC voltage, a valley fill power supply circuit that supplies the DC voltage obtained by partially smoothing the output of the rectifier circuit to the inverter circuit, and a DC cut capacitor between the output terminals of the inverter circuit. And a drive transformer in which a primary winding is connected to a path through which a resonance current of the resonance load circuit flows, and a secondary winding provided separately at a control end of each switching element. An activation circuit for activating a switching operation of the pair of switching elements, wherein the valley fill power supply circuit is charged by an output of a rectifier circuit. A smoothing capacitor connected to a charging path of the smoothing capacitor, a choke for chopper, a diode for preventing backflow, and one of the pair of switching elements. The switching action of the pair of switching elements is performed by a feedback action of the driving transformer. In a power supply device for self-excited oscillation of an element, an ON width setting capacitor charged by a power supply voltage of a DC power supply is provided, and the ON width of one switching element is set to an ON width setting capacitor after the switching element is turned on. And a reset means for setting the charge of the ON-width setting capacitor to zero when the inverter circuit is started, characterized in that it comprises:
Since the reset means sets the charge of the ON width setting capacitor to zero at the time of starting the inverter circuit, the voltage across the ON width setting capacitor is not charged to the predetermined voltage at the time of starting, and therefore, the other control circuit has one side. Can be prevented from forcibly turning off the switching element, and the self-excited oscillation operation of the switching element can be reliably started.

According to the third aspect of the present invention, a pair of switching elements are connected between a rectifying circuit for rectifying an AC voltage of an AC power supply and a high-frequency diode having an impedance element connected in parallel between output terminals of the rectifying circuit. A DC cut capacitor, a resonance load circuit, and a series circuit of a primary winding of a driving transformer are connected between a connection point of both switching elements and one output terminal of the rectifier circuit, and each switching element is connected to the driving transformer. In response to the above, a secondary winding provided separately in the drive transformer is connected to a control terminal of each switching element, and an inverter circuit that self-oscillates both switching elements by a feedback action of the drive transformer, and the pair of switching circuits An activation circuit for activating a switching operation of the element; and a smoothing capacitor charged by an output of the rectifier circuit. A backflow prevention diode connected to the charging path of the smoothing capacitor, one of the pair of switching elements, and a choke for a chopper, and a valley filling power supply for supplying a DC voltage obtained by partially smoothing the output of the rectifier circuit to the inverter circuit. A power supply device comprising an ON width setting capacitor charged by a power supply voltage of a DC power supply, and an ON width of one of the switching elements is changed after the switching element is turned on. A reset circuit for setting the voltage between both ends by a time until the voltage is charged to a predetermined voltage; and reset means for setting the charge of the ON-width setting capacitor to zero when the inverter circuit is started. Since the charge of the ON width setting capacitor is set to zero when the inverter circuit starts, the ON width setting capacitor The voltage between both ends of the capacitor is not charged to a predetermined voltage, so that it is possible to prevent the other control circuit from forcibly turning off one of the switching elements, and to reliably start the self-excited oscillation operation of the switching element. be able to.

According to a fourth aspect of the present invention, in the second or third aspect of the invention, the choke for the chopper is also used as an inductance element constituting the resonance load circuit, and the number of parts is reduced to reduce the cost. Can be planned.

According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, the reset means sets the charge of the ON-width setting capacitor to zero according to a control signal input from a starting circuit. Thus, the same operations as those of the first to fourth aspects of the invention are achieved.

According to a sixth aspect of the present invention, in the invention of the fifth aspect, the starting circuit includes a trigger capacitor charged by an output voltage of the rectifier circuit and one of the trigger capacitors when the voltage across the trigger capacitor reaches the trigger voltage. A trigger element for applying a trigger signal to a control terminal of the switching element to turn on the switching element, wherein the control signal is a charging voltage of a trigger capacitor, and the resetting means includes a voltage across the trigger capacitor. Is smaller than the predetermined voltage, the charge of the ON-width setting capacitor is set to zero, and the same operation as the invention of claim 5 is achieved.

According to a seventh aspect of the present invention, in the first to fourth aspects of the present invention, the resonance load circuit has a primary winding connected between output terminals of the inverter circuit and a load connected to the secondary side. Comprising a transformer, wherein the reset means comprises:
The charge of the ON-width setting capacitor is set to zero according to the winding voltage generated in the auxiliary winding provided in the transformer.

According to an eighth aspect of the present invention, in the first to fourth aspects of the present invention, the reset means transfers the charge of the ON-width setting capacitor in accordance with a winding voltage generated in an auxiliary winding provided in the drive transformer. 2. The method according to claim 1, wherein the value is zero.
The same effects as those of the inventions of the fourth to fourth aspects are exerted.

According to a ninth aspect of the present invention, in the first to fourth aspects of the present invention, the resonance load circuit includes a discharge lamp having a preheating filament, and is provided with a preheating timer circuit for limiting a predetermined time from power-on. Until the timer operation of the preheating timer circuit ends, the output of the inverter circuit is reduced to supply a preheating current to the filament of the discharge lamp, and the resetting means performs the timer operation of the timer circuit for preheating while The charge of the ON width setting capacitor is set to zero, and the same operation as the inventions of claims 1 to 4 is achieved.

According to a tenth aspect of the present invention, in the first to fourth aspects of the present invention, the resonance load circuit has a primary winding connected between output terminals of the inverter circuit and a load connected to the secondary side. The DC power supply includes a DC power supply circuit that rectifies and smoothes a winding voltage generated in an auxiliary winding provided in the transformer and converts the winding voltage into a substantially constant DC voltage. The present invention is characterized in that it has the same function as the first to fourth aspects of the present invention.

[0036]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 shows a circuit diagram of a power supply device of the present embodiment. In the power supply device according to the present embodiment, a reset circuit (reset means) 12 for releasing the electric charge accumulated in the capacitor C5 of the control circuit 10 at the time of turning on the power and setting it to substantially zero is provided in the power supply device described in the conventional example. ing. Since the configuration other than the reset circuit 12 is the same as that of the above-described conventional power supply device, the same components are denoted by the same reference numerals and description thereof will be omitted. Since the circuit configuration of the resonance load circuit 7 is the same as the circuit shown in FIG. 20 described in the conventional example, illustration and description are omitted.

The reset circuit 12 has a series circuit of resistors R11 and R12 connected in parallel with the capacitor C4 of the starting circuit 9, a base-emitter connected in parallel with the resistor R12, and a collector connected to the resistors R5 and R6. And a switching element Q6 composed of an NPN type transistor connected to the connection point of.

Next, the operation of this circuit will be briefly described with reference to FIGS. 2A shows the voltage VC4 across the capacitor C4, FIG. 2B shows the collector-emitter voltage VQ6 _CE of the switching element Q6, and FIG. 2C.
Is the gate-source voltage VQ2 of the switching element Q2.
gs, respectively. When power is turned on (at startup)
The other circuit operations are the same as the circuit operation of the power supply device described in the conventional example, and the description is omitted.

When the AC power supply 1 is turned on at time t10, a charging current flows through the capacitor C4 of the starting circuit 9 via the resistor R4, and the voltage across the capacitor C4 increases (see FIG. 2A). When the voltage VC4 across the capacitor C4 reaches the breakover voltage of the trigger element TD1 at time t12, the trigger element TD1 conducts, and the electric charge accumulated in the capacitor C4 flows into the gate of the switching element Q2, and at time t13, the switching element Q2 turns on.

Thus, the rectifier circuit 3—filter circuit 4
-Diode D1-Capacitor C1-Resonant load circuit 7-
Primary winding of driving transformer DT1-switching element Q2
-Filter circuit 4-Route of rectifier circuit 3 and rectifier circuit 3-
Filter circuit 4-Diode D1-Diode D2 (capacitor C2) -Smoothing capacitor C0-Choke L1-
A current flows through the diode D3, the primary winding of the driving transformer DT1, the switching element Q2, the filter circuit 4, and the rectifier circuit 3. At this time, the drive transformer DT1 applies an on-direction bias to the switching element Q2 and keeps the switching element Q1 off.
2 is completely on. Thereafter, when the resonance current is reversed by the resonance action of the resonance load circuit 7, the drive transformer DT
1, the switching element Q1 is turned on, the switching element Q2 is turned off, and the switching elements Q1, Q
2 performs a self-excited oscillation operation.

By the way, in the reset circuit 12, at time t11 before the trigger signal is input to the gate of the switching element Q2 via the trigger element TD1,
The voltage VC4 across the capacitor C4 is connected to the resistors R11 and R12.
The constants such as the resistance ratio of the resistors R11 and R12 are set so that the divided voltage reaches the threshold voltage of the switching element Q6. Therefore, the switching element Q6 is turned on before the switching element Q2 is turned on. Turns on. When the switching element Q6 is turned on, both ends of the resistor R6 are short-circuited via the switching element Q6, and the electric charge accumulated in the capacitor C5 is released via the resistor R7 and the switching element Q6 to become zero. The element Q3 is turned off.

As described above, since the reset circuit 12 forcibly turns off the switching element Q3 when the power is turned on, when the trigger signal is input to the gate of the switching element Q2, the gate / source of the switching element Q2 is turned off. The switching element Q2 is turned on by a trigger signal input via the trigger element TD1 without causing a short circuit between the switching elements Q3 and the self-excited oscillation operation of the switching elements Q1 and Q2 is reliably started. Can be.

(Embodiment 2) FIG. 3 shows a circuit diagram of a power supply device of this embodiment. In the present embodiment, in the power supply device of the first embodiment, a capacitor C11 is connected in parallel with the resistor R12 of the reset circuit 12, and the voltage across the capacitor C4 is divided by the resistors R11 and R12 and smoothed by the capacitor C11. The voltage is applied to the base of the switching element Q6. Since the circuit configuration and operation other than the capacitor C11 are the same as those of the first embodiment, the same components are denoted by the same reference numerals and description thereof will be omitted.

In the starting circuit 9, when the power is turned on, a charging current flows from the rectifier circuit 3 to the capacitor C4 via the filter circuit 4 and the resistor R4, and the capacitor C4
Of the trigger element TD1 reaches the breakover voltage of the trigger element TD1, the trigger element TD1 conducts, a trigger signal is input to the gate of the switching element Q2, and the switching element Q2 is turned on.
1 and Q2 have started the self-excited oscillation operation.

At this time, in the reset circuit 12, as described in the first embodiment, the voltage between both ends of the capacitor C4 is divided by the resistors R11 and R12.
Is applied to the base of the switching element Q6. When the voltage across the capacitor C11 reaches the threshold voltage of the switching element Q6, the switching element Q6 is turned on, the charge stored in the capacitor C5 is set to zero, and the switching element Q3 is forcibly turned off. The trigger signal applied to the gate of the switching element Q2 is prevented from being pulled out via the switching element Q3. Here, in this circuit, a capacitor C11 is connected in parallel with the resistor R12, and the resistor R11,
Since the voltage divided by R12 is smoothed by the capacitor C11, the voltage of the capacitor C
4 even if the voltage across both ends decreases.
The timing at which the switching element Q6 is turned off can be sent without the potential at the connection point of the abruptly dropping. Therefore, the timing at which the switching element Q3 is turned on can be delayed, and the switching element Q3 can be turned off.
2 is prevented from being pulled out for as long as possible, and the switching elements Q1, Q2
2 can be reliably performed.

(Embodiment 3) FIG. 4 shows a circuit diagram of a power supply device of this embodiment. In the present embodiment, in the power supply device according to the first embodiment, the cathode of the diode D3 is connected to the connection point of the capacitor C1 and the resonance load circuit 7, and
Choke L1 is eliminated. The circuit configuration and operation other than the diode D3 and the choke L1 are the same as those of the first embodiment.
Therefore, the same components are denoted by the same reference numerals and description thereof will be omitted. Since the circuit configuration of the resonance load circuit 7 is the same as the circuit shown in FIG. 20 described in the conventional example, illustration and description are omitted.

In this circuit, the cathode of the diode D3 is connected to the connection point between the capacitor C1 and the resonance load circuit 7, and the inductance component on the primary side of the transformer LT1 constituting the resonance load circuit 7 causes the valley filling power supply circuit 5 Since the choke L1 is also used, the choke L1 can be eliminated, the number of parts can be reduced, and the cost can be reduced.

(Embodiment 4) Embodiment 4 of the present invention is shown in FIG.
This will be described with reference to FIG. In the power supply device of the third embodiment, a series circuit of the resistor R4 and the capacitor C4 is connected between the output terminals of the filter circuit 4. However, in the power supply device of the present embodiment, two resistors R4a, R
4b, one end of the resistor R1a is connected to the output terminal on the high voltage side of the filter circuit 4, the other end of the resistor R1a is connected to the connection point of the discharge lamp La1 and the capacitor C8, and the auxiliary winding N3 of the transformer LT1 is connected. One end of the resistor R4b is connected to a connection point between the resistor R4b and the discharge lamp La2.
The other end of 4b is connected to the capacitor C4. Further, in the control circuit 10, a resistor R14 is connected between the diode D7 and the collector of the switching element Q3,
A switching element Q7 composed of a PNP transistor is connected between the emitter and the base in parallel with 14, and a collector of the switching element Q7 is connected to an emitter of the switching element Q3. Since the basic circuit configuration and operation of the power supply device are the same as those of the power supply device of the first or third embodiment, the same components are denoted by the same reference numerals and description thereof will be omitted.

In this circuit, the capacitor C4 of the starting circuit 9
Since the filaments f12 and f21 of the discharge lamps La1 and La2 are interposed in the path through which the charging current flows through the discharge lamp L,
If a1 or La2 is removed, the charging current stops flowing through the capacitor C4, and the trigger signal is no longer input to the gate of the switching element Q2. Therefore, the oscillation operation of the inverter circuit 6 can be stopped. As described above, in the present circuit, the starting circuit 9 is provided with the no-load detection function, and the no-load state is detected to stop the oscillation operation of the inverter circuit 6. Can be prevented from joining.

In the power supply device of the present embodiment, the output of the valley filling power supply circuit 5 (ie, the voltage across the capacitor C3)
Is divided by resistors R5 and R6, and a voltage smoothed by a capacitor C6 is used as an operating power supply of the control circuit 10.
As shown in FIG. 7, the rectified output of the rectifier circuit 3 input through the filter circuit 4 is divided by resistors R5 and R6.
Further, the voltage smoothed by the capacitor C6 may be used as the operation power supply of the control circuit 10, and the same effects as those of the above-described power supply device can be obtained. Further, in this circuit, the choke of the valley filling power supply circuit 5 is replaced by a transformer LT constituting the resonance load circuit 7.
1, the cathode of diode D3 is connected to the connection point between resonance load circuit 7 and drive transformer DT1, and choke L1 is connected between smoothing capacitor C0 and diodes D3 and D5. Needless to say, it may be inserted.

(Embodiment 5) FIG. 8 shows Embodiment 5 of the present invention.
This will be described with reference to FIG. In the power supply device of the first embodiment, a voltage obtained by dividing the voltage between both ends of the capacitor C4 by the resistors R9 and R10 is applied to the base of the switching element Q6. In the present embodiment, the transformer LT1 forming the resonance load circuit 7 is used. , An auxiliary winding N4 magnetically coupled to the primary side is provided, and a diode D12 is provided between both ends of the auxiliary winding N4.
, A series circuit of resistors R11 and R12 is connected, and a capacitor C11 is connected in parallel with the resistor R12. A switching element Q10 composed of a PNP transistor is connected to a connection point between the resistors R11 and R12 via a resistor R13.
And the switching element Q10
Are connected to the emitter and collector of the switching element Q4, respectively. Since the configuration and operation other than the reset circuit 12 and the resonance load circuit 7 are the same as those of the first embodiment, the same components are denoted by the same reference numerals and description thereof will be omitted.

Here, when the power is turned on and before the inverter circuit 6 performs the self-excited oscillation operation, the transformer LT
No voltage is generated in the auxiliary winding N4 magnetically coupled to the primary side of the first element 1. Therefore, the potential at the connection point between the resistors R11 and R12 becomes substantially zero, so that the switching element Q10 is turned on and stored in the capacitor C5. The applied charge becomes zero, and the switching element Q3 is turned off.

On the other hand, when the inverter circuit 6 starts a self-excited oscillation operation and a voltage is generated in the auxiliary winding N4 magnetically coupled to the primary side of the transformer LT1, a current flows through the capacitor C11 via the diode D12 and the resistor R11. Then, the capacitor C11 is charged. And the capacitor C11
When the base-emitter voltage of the switching element Q10 falls below the threshold voltage, the switching element Q10 is turned off, and the ON width of the switching element Q2 is modulated by the control circuit 10.

As described above, when the power is turned on, the electric charge accumulated in the capacitor C5 by the reset circuit 12 becomes zero and the switching element Q3 is forcibly turned off, so that the trigger signal input to the gate of the switching element Q2 is generated. It is not pulled out through the switching element Q3, and the self-excited oscillation operation of the switching elements Q1 and Q2 can be reliably started when the power is turned on.

In the power supply of the present embodiment, the cathode of the diode D3 is connected to the resonance load circuit 7 and the driving transformer D.
Although it is connected to the connection point of T1, as shown in FIG.
The cathode of the diode D3 may be connected to the connection point between the capacitor C1 and the resonance load circuit 7, and the choke L1 of the valley filling power supply circuit 5 is also used by the inductance component on the primary side of the transformer LT1 constituting the resonance load circuit 7. Therefore, the choke L1 can be eliminated, the number of components can be reduced, and the cost can be reduced.

8 and FIG. 10, the auxiliary winding N4 is connected to the transformer L in the resonance load circuit 7.
Although it is magnetically coupled to the primary side of T1, as shown in FIG. 11, the auxiliary winding N4 may be magnetically coupled to the secondary side of the transformer LT1, and the same effects as described above can be obtained.

(Embodiment 6) FIG. 1 shows Embodiment 6 of the present invention.
This will be described with reference to FIG. In the power supply device of FIG. 8 described in the fifth embodiment, a parallel circuit of a resistor R12 and a capacitor C11 is connected between both ends of an auxiliary winding N4 provided in a transformer LT1 via a series circuit of a diode D12 and a resistor R11. However, in the power supply device of the present embodiment, the auxiliary winding n1 magnetically coupled to the primary winding of the drive transformer DT1 is provided, and a diode D12 and a resistor R11 are connected between both ends of the auxiliary winding n1 via a series circuit. , Resistor R12 and capacitor C
11 is connected in parallel. Since the circuit configuration and operation other than the auxiliary winding n1 and the reset circuit 12 are the same as those of the power supply device of the fifth embodiment, the same components are denoted by the same reference numerals and description thereof will be omitted.

Here, at the time when the power is turned on and before the inverter circuit 6 performs the self-excited oscillation operation, no voltage is generated in the auxiliary winding n1 magnetically coupled to the primary winding of the driving transformer DT1. Therefore, the resistors R11 and R12
Becomes substantially zero, the switching element Q
10 turns on, the electric charge stored in the capacitor C5 becomes zero, and the switching element Q3 turns off.

On the other hand, when the inverter circuit 6 starts the self-excited oscillation operation and a voltage is generated in the auxiliary winding n1 magnetically coupled to the primary winding of the driving transformer DT1, the diode D12
Then, a current flows through the capacitor C11 via the resistor R11 and the capacitor C11 is charged. Then, the voltage across the capacitor C11 increases, and the switching element Q10
When the base-emitter voltage falls below the threshold voltage,
The switching element Q10 is turned off, and the ON width of the switching element Q2 is modulated by the control circuit 10.

As described above, when the power is turned on, the electric charge accumulated in the capacitor C5 by the reset circuit 12 becomes zero and the switching element Q3 is forcibly turned off, so that the trigger signal input to the gate of the switching element Q2 is generated. It is not pulled out through the switching element Q3, and the self-excited oscillation operation of the switching elements Q1 and Q2 can be reliably started when the power is turned on.

In the power supply of the present embodiment, the cathode of the diode D3 is connected to the resonance load circuit 7 and the driving transformer D.
Although connected to the connection point of T1, as shown in FIG.
The cathode of the diode D3 may be connected to the connection point between the capacitor C1 and the resonance load circuit 7, and the choke L1 of the valley filling power supply circuit 5 is also used by the inductance component on the primary side of the transformer LT1 constituting the resonance load circuit 7. Therefore, the choke L1 can be eliminated, the number of components can be reduced, and the cost can be reduced.

In the power supply device shown in FIGS. 12 and 13, the output of the valley filling power supply circuit 5 (ie, the capacitor C3
Is divided by resistors R5 and R6, and a voltage smoothed by a capacitor C6 is used as an operating power supply of the control circuit 10. As shown in FIG. The rectified output of circuit 3 is connected to resistors R5 and R6.
And the voltage smoothed by the capacitor C6 may be used as the operating power supply of the control circuit 10, and the same effects as those of the above-described power supply device can be obtained.

(Embodiment 7) Embodiment 7 of the present invention is shown in FIG.
This will be described with reference to FIG. In the present embodiment, in the power supply device of the first embodiment, a capacitor C12 connected between the output terminals of the DC power supply E, a Zener diode ZD5 having a cathode connected to the high-potential side end of the capacitor C12, and a Zener diode ZD5 The base and the emitter are connected between the anode and the low potential side end of the capacitor C12, and the collector is connected to the capacitor C1 via the resistor R15.
The reset circuit 12 is constituted by a switching element Q8 composed of an NPN transistor connected to the high potential side end of the switching element Q2 and a switching element Q9 composed of an NPN transistor whose base and emitter are respectively connected to the collector and the emitter of the switching element Q8. The collector of the switching element Q9 is connected to a resistor R5 and a capacitor C
6 are connected. Since the circuit configuration and operation other than the reset circuit 12 are the same as those of the first embodiment, the same components are denoted by the same reference numerals and description thereof will be omitted.

Here, the DC power source E is turned on at the same time as the AC power source 1, and the capacitor C12 is charged by the DC power source E. The switching element Q8 is turned off and the switching element Q9 is turned on until the voltage between both ends of the capacitor C12 reaches the Zener voltage of the Zener diode ZD5 after the power is turned on, so that the charge accumulated in the capacitor C5 is reduced. It is released through R7 and the switching element Q9, becomes substantially zero, and the switching element Q3 is turned off.

Thereafter, when the voltage between both ends of the capacitor C9 reaches the Zener voltage of the Zener diode ZD5, the Zener diode ZD5 conducts, a current flows to the base of the switching element Q8, and the switching element Q8 is turned on and the switching element Q9 is turned off. Therefore, the charging current flows through the capacitor C5, and the ON width of the switching element Q2 is modulated by the control circuit 10.

As described above, when the power is turned on, the electric charge accumulated in the capacitor C5 by the reset circuit 12 becomes zero and the switching element Q3 is forcibly turned off, so that the trigger signal input to the gate of the switching element Q2 is generated. It is not pulled out through the switching element Q3, and the self-excited oscillation operation of the switching elements Q1 and Q2 can be reliably started when the power is turned on.

In the power supply device of this embodiment, the cathode of the diode D3 is connected to the resonance load circuit 7 and the driving transformer D.
Although connected to the connection point of T1, as shown in FIG.
The cathode of the diode D3 may be connected to the connection point between the capacitor C1 and the resonance load circuit 7, and the choke L1 of the valley filling power supply circuit 5 is also used by the inductance component on the primary side of the transformer LT1 constituting the resonance load circuit 7. Therefore, the choke L1 can be eliminated, the number of components can be reduced, and the cost can be reduced.

(Embodiment 8) FIG. 9 shows Embodiment 8 of the present invention.
This will be described with reference to FIG. In the power supply device according to the first embodiment, the output voltage of the valley filling power supply circuit 5 is divided by the resistors R5 and R6, and the voltage smoothed by the capacitor C6 is divided by the other control circuit 10.
Although the reset circuit 12 that makes the electric charge stored in the capacitor C5 zero when the power is turned on is provided. However, in the power supply device of this embodiment, instead of providing the reset circuit 12, the resonance load circuit 7 is used. Trans LT
1 is provided with an auxiliary winding N4 magnetically coupled to the primary side (FIG. 9).
), A resistor R6 and a capacitor C6 across a series circuit of a diode D13 and a resistor R5 between both ends of the auxiliary winding N4.
After the voltage generated in the auxiliary winding N4 is rectified by the diode D13, the resistors R5 and R6 are connected.
, And the voltage smoothed by the capacitor C6 is used as the operating power supply of the control circuit 10. Here, resistors R5 and R
6, a capacitor C6 and a diode D13 constitute a DC power supply circuit 10a. Since the circuit configuration and operation other than the resonance load circuit 7 and the control circuit 10 are the same as those of the power supply device of the first embodiment, the same components are denoted by the same reference numerals and description thereof will be omitted. .

In this circuit, the transformer LT of the resonance load circuit 7 is used.
The voltage generated in the auxiliary winding N <b> 4 provided in 1 is rectified and divided, and a smoothed DC voltage is used as an operation power supply of the control circuit 10. Therefore, when the power is turned on and before the inverter circuit 6 starts the self-excited oscillation operation, no voltage is generated in the auxiliary winding N4 and the DC power supply circuit 1
0a is zero, the capacitor C5
Becomes zero, the switching element Q3 is kept in the OFF state, and the trigger signal applied to the gate of the switching element Q2 is not pulled out via the switching element Q3. By starting, the self-excited oscillation operation of the switching elements Q1 and Q2 can be reliably started. That is,
When the power is turned on, the capacitor C
Reset means for making the electric charge of No. 5 zero is constituted.

When the inverter circuit 6 starts the self-excited oscillation operation, a voltage is generated in the auxiliary winding N4 provided on the primary side of the transformer LT1, and operation power is supplied to the remote control circuit 10, and the remote control circuit 10 is operated. 10, the ON width of the switching element Q2 is modulated.

In the power supply device of this embodiment, the voltage generated in the auxiliary winding N4 provided on the primary side of the transformer LT1 is rectified, divided, and further smoothed to obtain a DC voltage. The auxiliary winding N4 is magnetically coupled to the transformer LT1 on the secondary side as shown in FIG.
And a diode D13 is provided between both ends of the auxiliary winding N4.
A parallel circuit of a resistor R6 and a capacitor C6 may be connected through a series circuit of a resistor R5 and a resistor D6 after rectifying the voltage generated in the auxiliary winding N4 by a diode D13.
5, a voltage obtained by dividing the voltage by R6 and smoothing by the capacitor C6 may be used as the operating power supply of the control circuit 10.

Here, before the inverter circuit 6 starts the self-excited oscillation operation, no voltage is generated in the auxiliary winding N4 and the charge of the capacitor C5 is zero. Keeps the off state, and the trigger signal applied to the gate of the switching element Q2 is not pulled out through the switching element Q3. Therefore, when the trigger signal is input, the switching element Q2 is activated and the switching elements Q1 and Q2 are turned off. The self-excited oscillation operation can be reliably started. On the other hand, the inverter circuit 6
Starts self-excited oscillation operation, a voltage is generated in the auxiliary winding N4 provided on the secondary side of the transformer LT1, and the other control circuit 10
Is supplied with the operating power supply, and the ON width of the switching element Q2 is modulated by the control circuit 10.

In the power supply device of this embodiment, the cathode of the diode D3 is connected to the connection point between the resonance load circuit 7 and the drive transformer DT1, but as shown in FIG. 18, the cathode of the diode D3 is connected to the capacitor C1. Also, the choke L1 may be connected to the connection point of the resonance load circuit 7, and the choke L1 of the valley filling power supply circuit 5 is also used by the inductance component of the primary side of the transformer LT1 constituting the resonance load circuit 7. Thus, the number of parts can be reduced and cost can be reduced.

In the power supply device of each of the above-described embodiments, the preheating alternative circuit 11 described in the conventional example may be added, and the same effect as described above can be obtained. Further, the other control circuit 12 may control the charge of the capacitor C5 to zero during the preheating period of the discharge lamps La1 and La2 according to the signal input from the preheating other control circuit 11, as described above. The same effect as described above can be obtained. Further, it is needless to say that the circuit configuration of the main circuit is not limited to the above-described circuit, and may be appropriately changed within the technical idea of the present invention.

[0076]

As described above, according to the first aspect of the present invention, there is provided a rectifier circuit for rectifying an AC voltage of an AC power supply, and a DC converter for generating a DC voltage having a smoothing capacitor and smoothing the output of the rectifier circuit. An inverter circuit having a series circuit of a pair of switching elements that are turned on / off alternately, and converting an output of the DC conversion circuit into an AC voltage by switching the output of the pair of switching elements; The primary winding is connected to the resonant load circuit connected via the cut capacitor and the path through which the resonant current of the resonant load circuit flows, and the secondary winding provided separately to the control terminal of each switching element is connected. And a starting circuit for starting the switching operation of the pair of switching elements, and the feedback operation of the driving transformer In a power supply device that self-oscillates a pair of switching elements, the power supply apparatus includes an ON width setting capacitor that is charged by a power supply voltage of a DC power supply, and sets the ON width of one switching element to ON after the switching element is turned on. A control circuit for setting the voltage between both ends of the width setting capacitor until the voltage is charged to a predetermined voltage; and reset means for setting the charge of the ON width setting capacitor to zero when the inverter circuit is started. A feature is that the reset means makes the charge of the ON width setting capacitor zero at the start of the inverter circuit, so that the voltage across the ON width setting capacitor is not charged to a predetermined voltage at the time of start, and therefore the other control is performed. This prevents the circuit from forcibly turning off one of the switching elements, and the self-excitation of the switching element There is an effect that it is possible to reliably start the operation.

According to a second aspect of the present invention, there is provided a rectifier circuit for rectifying an AC voltage of an AC power supply, and a series circuit of a pair of switching elements which are turned on / off alternately, and the DC voltage is switched by the pair of switching elements. An inverter circuit that converts the output of the rectifier circuit into an AC voltage, a valley fill power supply circuit that supplies the DC voltage obtained by partially smoothing the output of the rectifier circuit to the inverter circuit, and a DC cut capacitor between the output terminals of the inverter circuit. A resonant load circuit connected
A drive transformer in which a primary winding is connected to a path through which a resonance current of a resonance load circuit flows, and a secondary winding provided separately at a control end of each switching element is connected, and the switching operation of the pair of switching elements is performed. The power supply circuit has a smoothing capacitor charged by the output of the rectifier circuit, a choke for a chopper, a backflow prevention diode, and a A power supply device configured to be connected to one of the switching elements and self-oscillating the pair of switching elements by a feedback action of the drive transformer, including an on-width setting capacitor charged by a power supply voltage of a DC power supply; The ON width of one of the switching elements is changed to an ON width setting command after the switching element is turned on. It is characterized in that it is provided with a control circuit for setting by the time until the voltage between both ends of the capacitor is charged to a predetermined voltage, and reset means for making the charge of the ON-width setting capacitor zero when the inverter circuit is started, Since the reset means sets the charge of the ON width setting capacitor to zero at the time of starting the inverter circuit, the voltage across the ON width setting capacitor is not charged to the predetermined voltage at the time of starting, and therefore, the other control circuit has one side. It is possible to prevent the switching element from being forcibly turned off, and to have an effect that the self-excited oscillation operation of the switching element can be reliably started.

According to a third aspect of the present invention, a pair of switching elements are connected between a rectifier circuit for rectifying an AC voltage of an AC power supply and a high-frequency diode having an impedance element connected in parallel between output terminals of the rectifier circuit. A DC cut capacitor, a resonance load circuit, and a series circuit of a primary winding of a driving transformer are connected between a connection point of both switching elements and one output terminal of the rectifier circuit, and each switching element is connected to the driving transformer. In response to the above, a secondary winding provided separately in the drive transformer is connected to a control terminal of each switching element, and an inverter circuit that self-oscillates both switching elements by a feedback action of the drive transformer, and the pair of switching circuits A starter circuit for starting a switching operation of the element; and a smoothing capacitor charged by an output of the rectifier circuit. A valley filling power supply circuit for connecting a reverse current prevention diode to one of the pair of switching elements and a chopper choke in a charging path of the capacitor and supplying a DC voltage obtained by partially smoothing the output of the rectifier circuit to an inverter circuit. A power supply device having an on-width setting capacitor charged by the power supply voltage of the DC power supply, and having the on-width of one of the switching elements set at both ends of the on-width setting capacitor after the switching element is turned on. A reset circuit that sets the charge of an on-width setting capacitor to zero when the inverter circuit is started, wherein the reset means is provided with: Since the charge of the ON width setting capacitor is set to zero when the inverter circuit is started, the ON width setting capacitor is The voltage between both ends of the sensor is not charged to a predetermined voltage, so that it is possible to prevent another control circuit from forcibly turning off one of the switching elements, and to reliably start the self-excited oscillation operation of the switching element. There is an effect that can be.

According to a fourth aspect of the present invention, in the second or third aspect of the present invention, the choke for the chopper is also used as an inductance element constituting the resonance load circuit, and the number of parts is reduced to reduce the cost. There is an effect that it can be achieved.

According to a fifth aspect of the present invention, in the first to fourth aspects, the reset means sets the charge of the ON-width setting capacitor to zero according to a control signal input from a starting circuit. Thus, the same effects as those of the first to fourth aspects of the invention can be obtained.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the starting circuit includes a trigger capacitor charged by an output voltage of the rectifier circuit and one of the trigger capacitors when the voltage across the trigger capacitor reaches the trigger voltage. A trigger element for applying a trigger signal to a control terminal of the switching element to turn on the switching element, wherein the control signal is a charging voltage of a trigger capacitor, and the resetting means includes a voltage across the trigger capacitor. Is smaller than the predetermined voltage, the charge of the ON-width setting capacitor is set to zero, and the same effect as the invention of claim 5 is obtained.

According to a seventh aspect of the present invention, in the first to fourth aspects of the present invention, the resonance load circuit has a primary winding connected between output terminals of the inverter circuit and a load connected to the secondary side. 5. The invention according to claim 1, further comprising a transformer, wherein said reset means makes the charge of the ON-width setting capacitor zero according to a winding voltage generated in an auxiliary winding provided in said transformer. It has the same effect as.

According to an eighth aspect of the present invention, in the first to fourth aspects of the present invention, the reset means transfers the charge of the on-width setting capacitor in accordance with a winding voltage generated in an auxiliary winding provided in the drive transformer. It is characterized by being set to zero, and has the same effects as the inventions of claims 1 to 4.

According to a ninth aspect of the present invention, in the first to fourth aspects of the present invention, the resonance load circuit includes a discharge lamp having a filament for preheating, and is provided with a timer circuit for preheating for limiting a fixed time from power-on. Until the timer operation of the preheating timer circuit ends, the output of the inverter circuit is reduced to supply a preheating current to the filament of the discharge lamp, and the resetting means performs the timer operation of the timer circuit for preheating while The charge of the ON width setting capacitor is set to zero, and the same effects as those of the first to fourth aspects of the invention are obtained.

According to a tenth aspect of the present invention, in the first to fourth aspects of the present invention, the resonance load circuit has a primary winding connected between output terminals of the inverter circuit and a load connected to the secondary side. A transformer, and the DC power supply rectifies a winding voltage generated in an auxiliary winding provided in the transformer,
The DC power supply circuit converts the DC voltage into a substantially constant DC voltage, and the DC power supply circuit constitutes the reset unit. The same effects as those of the first to fourth aspects of the invention are obtained.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a power supply device according to a first embodiment.

FIGS. 2 (a) to 2 (c) are waveform diagrams of respective parts of the above.

FIG. 3 is a circuit diagram of a power supply device according to a second embodiment.

FIG. 4 is a circuit diagram of a power supply device according to a third embodiment.

FIG. 5 is a circuit diagram of a power supply device according to a fourth embodiment.

FIG. 6 is a main part circuit diagram of the same.

FIG. 7 is a circuit diagram of another power supply device according to the embodiment.

FIG. 8 is a circuit diagram of a power supply device according to a fifth embodiment.

FIG. 9 is a main part circuit diagram of the same.

FIG. 10 is a circuit diagram of another power supply device according to the embodiment.

FIG. 11 is a main part circuit diagram of another power supply device of the above power supply system.

FIG. 12 is a circuit diagram of a power supply device according to a sixth embodiment.

FIG. 13 is a circuit diagram of another power supply device according to the embodiment.

FIG. 14 is a circuit diagram of another power supply device of the above power supply system.

FIG. 15 is a circuit diagram of a power supply device according to a seventh embodiment.

FIG. 16 is a circuit diagram of another power supply device according to the embodiment.

FIG. 17 is a circuit diagram of a power supply device according to an eighth embodiment.

FIG. 18 is a circuit diagram of another power supply device according to the embodiment.

FIG. 19 is a circuit diagram of a conventional power supply device.

FIG. 20 is a main part circuit diagram of the same.

FIGS. 21A to 21C are waveform diagrams of respective parts of the above.

FIGS. 22 (a) to (e) are waveform diagrams of respective parts of the above.

FIGS. 23 (a) to 23 (c) are waveform diagrams of respective parts of the above.

[Explanation of symbols]

 5 Valley filling power supply circuit 6 Inverter circuit 7 Resonant load circuit 10 Other control circuit 12 Reset circuit C5 Capacitor DT1 Drive transformer Q1, Q2 Switching element

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Joji Oyama 1048 Odakadoma, Kadoma, Osaka Prefecture Matsushita Electric Works, Ltd. Terms (reference) 5H007 AA03 CA02 CB03 CB06 CB09 CB17 CC12 EA02 GA01

Claims (10)

[Claims] A rectifier circuit for rectifying an AC voltage of an AC power supply, a DC converter circuit having a smoothing capacitor to generate a DC voltage having a smoothed output of the rectifier circuit, and a pair of switching elements that are turned on / off alternately. An inverter circuit that has a series circuit and converts the output of the DC conversion circuit to an AC voltage by switching the output of the pair of switching elements;
A resonant load circuit connected between output terminals of the inverter circuit via a DC cut capacitor, and a primary winding connected to a path through which a resonant current of the resonant load circuit flows,
A drive transformer in which a secondary winding provided separately to a control end of each switching element is connected, and a starting circuit that starts a switching operation of the pair of switching elements,
In a power supply device for self-excited oscillation of the pair of switching elements by a feedback action of the drive transformer, an on-width setting capacitor charged by a power supply voltage of a DC power supply is provided.
After the switching element is turned on, the other control circuit is set by the time until the voltage across the ON width setting capacitor is charged to a predetermined voltage, and the charge of the ON width setting capacitor is reduced to zero when the inverter circuit is started. And a reset means for resetting the power supply. 2. A rectifier circuit for rectifying an AC voltage of an AC power supply, and a series circuit of a pair of switching elements that are turned on / off alternately. The DC voltage is converted into an AC voltage by switching the DC voltage with the pair of switching elements. An inverter circuit, and a valley fill power supply circuit for supplying a DC voltage obtained by partially smoothing the output of the rectifier circuit to the inverter circuit,
A resonant load circuit connected between output terminals of the inverter circuit via a DC cut capacitor, and a primary winding connected to a path through which a resonant current of the resonant load circuit flows,
A drive transformer in which a secondary winding provided separately to a control end of each switching element is connected, and a starting circuit that starts a switching operation of the pair of switching elements,
The valley fill power supply circuit has a smoothing capacitor charged by the output of the rectifier circuit, and connects a choke for chopper, a backflow prevention diode, and one of the pair of switching elements to a charging path of the smoothing capacitor. Composed,
In a power supply device for self-excited oscillation of the pair of switching elements by a feedback action of the drive transformer, an on-width setting capacitor charged by a power supply voltage of a DC power supply is provided.
After the switching element is turned on, the other control circuit is set by the time until the voltage across the ON width setting capacitor is charged to a predetermined voltage, and the charge of the ON width setting capacitor is reduced to zero when the inverter circuit is started. And a reset means for resetting the power supply. 3. A rectifier circuit for rectifying an AC voltage of an AC power supply, and a pair of switching elements connected between output terminals of the rectifier circuit through a high-frequency diode having an impedance element connected in parallel. A DC cut capacitor, a resonance load circuit, and a series circuit of a primary winding of a drive transformer are connected between a connection point of the rectifier circuit and one output terminal of the rectifier circuit. An inverter circuit that connects a secondary winding provided separately to the drive transformer to the control terminal of each switching element and causes both switching elements to self-oscillate by the feedback action of the drive transformer, and a switching operation of the pair of switching elements. A starting circuit for starting, and a smoothing capacitor charged by an output of the rectifier circuit; A backflow prevention diode, one of the pair of switching elements, a chopper choke connected thereto, and a valley filling power supply circuit for supplying a DC voltage obtained by partially smoothing the output of the rectifier circuit to the inverter circuit. Power supply device, comprising an ON width setting capacitor charged by the power supply voltage of the DC power supply, the ON width of one switching element,
After the switching element is turned on, the other control circuit is set by the time until the voltage across the ON width setting capacitor is charged to a predetermined voltage, and the charge of the ON width setting capacitor is reduced to zero when the inverter circuit is started. And a reset means for resetting the power supply. 4. The power supply device according to claim 2, wherein the choke for the chopper is also used as an inductance element constituting the resonance load circuit. 5. The power supply device according to claim 1, wherein said reset means makes the charge of the ON width setting capacitor zero according to a control signal input from a start circuit. 6. The triggering circuit according to claim 1, wherein the trigger circuit is configured to apply a trigger signal to a control terminal of one of the switching elements when a voltage across the trigger capacitor reaches a trigger voltage. A trigger element for turning on the switching element, wherein the control signal is a charging voltage of a trigger capacitor, and the reset means is provided for setting an ON width when a voltage across the trigger capacitor is lower than a predetermined voltage. The power supply device according to claim 5, wherein the electric charge of the capacitor is set to zero. 7. The resonance load circuit includes a transformer in which a primary winding is connected between output terminals of an inverter circuit and a load is connected on a secondary side, and the reset means includes:
5. The power supply device according to claim 1, wherein the charge of the ON-width setting capacitor is reduced to zero according to a winding voltage generated in an auxiliary winding provided in the transformer. 8. The apparatus according to claim 1, wherein said reset means sets the charge of the ON-width setting capacitor to zero in accordance with a winding voltage generated in an auxiliary winding provided in the drive transformer.
A power supply device according to any one of claims 1 to 4. 9. The resonance load circuit includes a discharge lamp having a filament for preheating, a preheating timer circuit for time limiting a predetermined time from the time of turning on the power supply, and a time period until the time operation of the timer circuit for preheating ends. The preheating current is supplied to the filament of the discharge lamp by lowering the output of the inverter circuit, and the reset means sets the charge of the ON width setting capacitor to zero while the preheating timer circuit performs the timed operation. The power supply device according to claim 1, wherein: 10. The resonance load circuit includes a transformer having a primary winding connected between output terminals of an inverter circuit and a load connected to a secondary side, and the DC power supply is provided in the transformer. 5. A DC power supply circuit for rectifying and smoothing a winding voltage generated in an auxiliary winding and converting it to a substantially constant DC voltage, wherein said DC power supply circuit constitutes said reset means. The power supply as described.