JP2008086089A - Power unit, discharge lamp lighting device, headlight device for vehicle, and vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power unit, which reduces the withstand voltage of a resonant capacitor and reduces dielectric loss and improves the efficiency, a discharge lamp device, a headlight for vehicle, and a vehicle. <P>SOLUTION: The power unit is equipped with a transformer 12 with a primary winding N1 connected to a series circuit composed of a DC power source 1 and a switching element 11, a smoothing capacitor 14 which is connected in parallel with a load 2, a diode 13 which is connected in series to the secondary winding N2, in a direction where a current excited in the secondary winding N2 of the transformer 12 flows when the switching element 11 is turned off, a resonant capacitor 15 which is connected via the smoothing capacitor 14 between both ends of the series circuit composed of the secondary winding N2 and the diode 13, an inductor 16 which is connected between the junction between capacitors 14 and 15 and the junction between the secondary winding N2 and the diode 13, and a diode 17 which is connected in a direction where the current flows from the secondary winding N2 when the switching element 11 is turned off, between both ends of the series circuit of the capacitors 14 and 15. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power supply device, a discharge lamp lighting device, a vehicle headlamp device, and a vehicle.

  2. Description of the Related Art Conventionally, a switching power supply device has been provided as a power supply device that converts and supplies a DC power source obtained by rectifying and smoothing a battery or an AC power source to a voltage level required by a load. An example of a discharge lamp lighting device that uses such a power supply device to light a high-intensity discharge lamp with a wide load voltage fluctuation range will be described with reference to FIGS.

  In this discharge lamp lighting device 20, the DC power supply voltage of the DC power supply 1 is stepped up and down to a voltage required by the high-intensity discharge lamp 23 by the DC-DC converter circuit 10, and then the DC output of the DC-DC converter circuit 10 is output. It is converted into an alternating voltage by the rectangular wave inverter circuit 21 and supplied to the high-intensity discharge lamp 23 via a starting circuit 22 for applying a high voltage to the unlit high-intensity discharge lamp 23 and starting it. The rectangular wave inverter circuit 21 includes a full bridge inverter circuit using the switching elements S1 to S4. The switching elements S1 to S4 of the rectangular wave inverter circuit 21 and the switching element 11 of the DC-DC converter circuit 10 are supplied from the control circuit 41. The drive circuits 42 and 24 are turned on / off based on the input control signal.

  The DC-DC converter circuit 10 is a so-called flyback converter, and a switching element 11 and a primary winding N1 of a transformer 12 are connected in series between both ends of a DC power source 1 and between both ends of a secondary winding N2 of the transformer 12. And a capacitor 14 is connected via a diode 13. The flyback converter can step up the input voltage beyond the turns ratio of the transformer 12, and the primary closed circuit and the secondary closed circuit are electrically separated, so that the output voltage range should be wide. The DC power supply voltage of the DC power supply 1 is higher than the minimum voltage required for the high-intensity discharge lamp 23, and the required maximum voltage (generally no-load voltage in the extinguished state). The present invention is also applicable to the discharge lamp lighting device 20 that is lower than the above.

  In this discharge lamp lighting device 20, the control circuit 41 detects the output voltage Vout and the output current Iout of the DC-DC converter circuit 10, performs feedback control based on the power command to be supplied to the high-intensity discharge lamp 23, The power supplied to the high-intensity discharge lamp 23 is controlled by controlling the switching frequency and on-duty of the switching element 11.

  By the way, when the load of the power supply device is a discharge lamp, the output voltage at the time of extinguishing should be as high as possible in order to ensure the starting voltage, for example, preferably about 400V. On the other hand, immediately after the start of discharge, the lamp voltage decreases to a voltage close to a short circuit (for example, about several volts to several tens of volts) and then enters stable lighting. The output voltage range is quite wide.

  Here, the current waveforms of the primary side current I1 and the secondary side current I2 of the transformer 12 during steady lighting are shown by solid lines in FIGS. Here, in order to improve efficiency, an example in which the control circuit 41 operates in the current boundary mode in which the switching element 11 is switched from OFF to ON using the drive circuit 42 after the secondary current I2 becomes substantially zero. Show.

  When a metal halide lamp that does not contain mercury is used as the discharge lamp, the load voltage during steady lighting is further reduced (for example, about 40 V), but when such a discharge lamp is lit under the same conditions as described above, The current waveforms of the primary side current I1 and the secondary side current I2 of the transformer 12 are as shown by broken lines in FIGS. 10B and 10C, and the slope of the secondary side current I2 becomes small. The energization period of the secondary current I2 becomes longer. Here, in the flyback converter, when the switching element 11 is turned on, the primary current I1 flows, whereby energy is accumulated in the transformer 12, and when the switching element 11 is turned off, the energy accumulated in the transformer 12 is released to the secondary side. Is done. Since the primary side current I1 and the secondary side current I2 are alternately energized, if the energization period of the secondary side current is long if the switching cycle is the same, the on-duty is inevitably reduced and the unit time per unit time The output current will decrease. Therefore, in order to output the same power, it is necessary to lengthen the ON time and increase the peak value of the primary current I1, but in this case, the transformer is increased in size or the current capacity of the switching element 11 is increased. Invited and expensive.

  Also, when the load voltage during steady lighting decreases, it is desirable to redesign the transformer 12 constituting the flyback converter according to the load voltage. Generally, when the load voltage decreases, the turn ratio can be reduced. However, there is a problem that the voltage applied to the switching element 11 rises at the time of no-load voltage output as the turn ratio decreases. In general, since a switching element with a high withstand voltage has high on-loss, it is necessary to use a switching element 11 having a larger capacity or to connect a plurality of switching elements 11 in parallel. There was a problem of inviting.

  Further, in the flyback type DC-DC converter circuit 10, the secondary side energization period becomes long and the output voltage is difficult to extract efficiently under the condition that the output voltage is particularly low immediately after the start of the discharge lamp. It was. Especially when supplying a large amount of power transiently when the load voltage, that is, the lamp voltage is low, in order to quickly start the light output immediately after starting, such as a high-intensity discharge lamp used in a vehicle headlamp device, There have been problems such as an increase in current flowing through the switching element and an increase in the size of the transformer 12.

  When the flyback type DC-DC converter circuit 10 is used in this way, there is a problem in that the power supply device is increased in size and cost. Therefore, the DC-DC converter circuit 10 having the circuit configuration shown in FIG. The one used is proposed (see, for example, Patent Document 1). In this power supply apparatus, the AC power supply AC is rectified by the rectifier DB and then smoothed by the smoothing capacitor C0 to generate the DC power supply.

  In the DC-DC converter circuit 10 shown in FIG. 11, the switching element 11 and the primary winding N1 of the transformer 12 are connected in series between both ends of the smoothing capacitor C0, and are respectively connected to both ends of the secondary winding N2 of the transformer 12. One end sides of the capacitors 14 and 15 are connected, and an inductor 16 is connected between the other ends of the capacitors 14 and 15. The cathodes of the diodes 13b and 13a are connected to both ends of the secondary winding N2 of the transformer 12, and the anodes of the diodes 13a and 13b are connected to the connection point of the capacitor 15 and the inductor 16.

  The DC-DC converter circuit 10 has a circuit configuration of a forward converter except for the capacitor 15. In the forward converter, normally, when the switching element 11 is turned on, a current also flows to the secondary side and power is supplied to the load. Therefore, if the secondary-side energization period for supplying power from the secondary side to the load becomes long, the on-duty also becomes large, which is advantageous when the output is large. However, the maximum output voltage is the number of transformer turns of the input voltage. Therefore, when the voltage difference between the no-load voltage and the lighting voltage is large, when the turn ratio is adjusted to the no-load voltage, the turn ratio becomes a very large value. There was a problem that it became smaller and caused a decrease in efficiency.

  However, in the circuit of FIG. 11, the energy excited on the secondary side of the transformer 12 when the switching element 11 is turned off is temporarily stored in the capacitor 15 by the flyback operation, and then the secondary of the transformer 12 is turned on when the switching element 11 is turned on. When the smoothing capacitor 14 is charged by the superimposed voltage of the side voltage and the voltage across the capacitor 15 and the capacitor 15 is no longer charged, the normal forward converter operation is performed to improve efficiency.

  Further, when the excitation energy generated on the secondary side of the transformer 12 due to the off operation of the switching element 11 is stored in the capacitor 15, the charging voltage of the capacitor 15 is made sufficiently higher than the output voltage, so that the charging voltage of the capacitor 15 Since the current flowing through the inductor 16 is rapidly increased and then the inductor current continues to flow through the secondary winding N2 due to the characteristics of the inductor 16, the secondary winding voltage when the switching element 11 is on (power supply voltage × turn ratio) ) Is lower than the load voltage, it is possible to extract necessary power from the power source to the load side. That is, since it is possible to cope with a load voltage higher than (power supply voltage × turn ratio), there is an advantage that it is not necessary to increase the turn ratio more than necessary.

Furthermore, since the basic operation of the DC-DC converter circuit 10 is the same as that of the forward converter, it is easy to take out a large output even under a condition where the output power is low, such as immediately after the start of the discharge lamp 23, and the vehicle headlamp device. This is advantageous compared to a flyback converter when it is necessary to apply a large amount of power transiently in order to quickly increase the light output, such as the high-intensity discharge lamp used in the present invention.
JP 2000-209852 A

  In the forward type DC-DC converter circuit 10 described above, the excitation energy excited on the secondary side of the transformer 12 is temporarily stored in the capacitor 15 when the switching element 11 is turned off, and then the transformer 12 is turned on when the switching element 11 is turned on. A voltage obtained by subtracting the output voltage (that is, the voltage across the smoothing capacitor 14) from the superimposed voltage of the secondary winding voltage and the charging voltage of the capacitor 15 is applied to the inductor 16. At this time, in order to increase the current flowing through the inductor 16 rapidly, the voltage across the capacitor 15 must be sufficiently higher than the load voltage, so that a step-up ratio larger than the turn ratio cannot be obtained. It is necessary to use a large element. In particular, considering no-load voltage, it is necessary to make the withstand voltage of the capacitor 15 larger than the no-load voltage, and there is a problem that the power supply device is increased in size and cost. Further, since a high-frequency voltage is applied to the capacitor 15, there is a problem that the induction loss increases as the voltage fluctuation range increases.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its object is to reduce the withstand voltage of a resonant capacitor, reduce inductive loss and improve efficiency, and discharge lamp lighting. An apparatus, a vehicle headlamp device, and a vehicle are provided.

  In order to achieve the above object, the invention of claim 1 is a closed circuit comprising at least a DC power source, a switching element and a first inductance element, a control unit for controlling on / off of the switching element, and both ends of the load circuit. A smoothing capacitor connected in between, a first rectifying element connected in series with the first inductance element in a direction in which a current excited in the first inductance element flows when the switching element is turned off, and at least a first A resonance capacitor connected via a smoothing capacitor between both ends of the series circuit of the first inductance element and the first rectifier element, and a connection point between the two capacitors and a connection point between the first inductance element and the first rectifier element A second inductance connected in between and forming a closed circuit with the first inductance element and the resonant capacitor And containing, between both ends of the series circuit of two capacitors, characterized in that it comprises a second rectifier element connected in a first direction in which a current flows from the inductance element when the switching element.

  According to a second aspect of the present invention, in the first aspect of the invention, the first inductance element includes a primary winding that forms a closed circuit together with at least a DC power source and a switching element, and the secondary winding includes the first rectifying element. A series circuit of both capacitors is connected between both ends of the series circuit of the secondary winding and the first rectifying element, and the secondary winding is connected to the second inductance element and A closed circuit is formed together with the resonant capacitor.

According to a third aspect of the present invention, in the first or second aspect of the present invention, in the first inductance element, the inductance value of an inductance component that forms a closed circuit together with the second inductance element and the resonant capacitor is L1, and the second inductance element When the inductance value of L2 is L2, the capacitance of the resonant capacitor is C1, and the switching period of the switching element is t _SW ,

It is characterized by.

  According to a fourth aspect of the present invention, in the first to third aspects of the invention, the energy stored in the first inductance element when the switching element is turned on is released to the series circuit of both capacitors when the switching element is turned off. The portion is characterized in that the switching element is not turned on again until the first inductance element finishes releasing the accumulated energy.

  According to a fifth aspect of the present invention, there is provided a load circuit including at least a discharge lamp as a load, and the power supply device according to any one of the first to fourth aspects for supplying power to the load circuit. .

  The invention of claim 6 is characterized in that, in the invention of claim 5, the discharge lamp comprises a metal halide lamp containing no mercury.

  A seventh aspect of the invention is a vehicular headlamp device, characterized in that it has the discharge lamp lighting device of the sixth aspect.

  The invention according to claim 8 is a vehicle, comprising the vehicle headlamp device according to claim 7.

  According to the first aspect of the present invention, when the switching element is turned on, the excitation energy is stored in the first inductance element from the DC power source via the switching element, and at the same time, the load and the smoothing capacitor are connected via the second inductance element, Current is supplied to the rectifying element 2 and when the switching element is turned off, the energy stored in the first inductance element is released to the resonance capacitor and the smoothing capacitor, and the energy stored in the first inductance element is released. When completed, the energy stored in the resonance capacitor is moved to the second inductance element by the resonance operation of the closed circuit formed by the resonance capacitor and the first and second inductance elements. The current flowing through the capacitor is increased by the charging voltage of the resonant capacitor. And then supplying the energy stored in the second inductance element to the load and the smoothing capacitor via the first inductance element, thereby generating a voltage higher than the voltage generated in the first inductance element. And a high step-up ratio can be obtained. Moreover, since the energy stored in the first inductance element is released to the smoothing capacitor and the resonance capacitor, the voltage across the resonance capacitor can be suppressed, and it is necessary to use an element with a high withstand voltage for the resonance capacitor. Therefore, there is an effect that the inductive loss can be reduced without increasing the size and cost of the power supply device. Furthermore, since the discharge time is shortened if the capacitance of the resonance capacitor is small, the on-duty can be increased, and as a result, the efficiency can be improved by reducing the peak value of the circuit current. Furthermore, the energy stored in the smoothing capacitor is such that, when the capacitance of the smoothing capacitor is sufficiently larger than the capacitance of the resonance capacitor, the excitation energy of the first inductance element increases toward the smoothing capacitor as the output voltage increases. Since much is accumulated, the effect of suppressing the capacitance of the resonant capacitor is also increased.

  According to the invention of claim 2, when the switching element is turned on, a current flows from the DC power source to the primary winding of the transformer via the switching element, and at the same time, the excitation energy is accumulated in the transformer, and at the same time, via the secondary winding of the transformer. Current is supplied to the second inductance element, the load and the smoothing capacitor, and the second rectifying element, and when the switching element is off, the energy stored in the transformer is smoothed from the secondary winding to the resonant capacitor. There is an effect that it can be discharged to the capacitor.

  According to the invention of claim 3, the excitation energy of the first inductance element can be quickly released to the resonance capacitor and the smoothing capacitor, or the energy stored in the resonance capacitor can be released in a short time, and the switching element can be turned on. Since the duty can be increased, the efficiency can be improved by reducing the peak value of the circuit current.

  According to the fourth aspect of the present invention, the control unit does not turn on the switching element until the energy stored in the first inductance element has been released, and therefore the control unit releases the energy stored in the first inductance element. There is an effect that a necessary time can be secured.

  According to the invention of claim 5, since the power supply device capable of obtaining a high step-up ratio without causing an increase in size and cost of the device is used, a discharge lamp having a low load voltage during steady lighting is used. It is possible to realize a small and low-cost discharge lamp lighting device that can cope with the above.

  According to the invention of claim 6, a metal halide lamp that does not contain mercury is used as a discharge lamp. Generally, a metal halide lamp that does not contain mercury has a lamp voltage that is about half that at the time of steady lighting compared to a lamp that contains mercury. Therefore, the difference between the load voltage (lamp voltage) during steady lighting and the no-load voltage during extinguishing is greater than that of lamps containing mercury. Since a power supply device that can obtain a high step-up ratio without incurring is used, a compact and low-cost discharge lamp lighting device that can be used even when using a discharge lamp with a low load voltage during steady lighting is realized. it can.

  According to the invention of claim 7, by using a power supply device that can obtain a high step-up ratio without incurring an increase in size and cost of the device, it is possible to use a discharge lamp having a wide voltage fluctuation range. Thus, a low-cost vehicle headlamp device can be realized.

  Since the invention of claim 8 is a vehicle and uses a small and low-cost vehicle headlamp device, a vehicle that does not require a large space as a mounting space for the vehicle headlamp device can be realized.

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

(Embodiment 1)
An embodiment of a power supply device according to the present invention will be described with reference to FIGS.

  FIG. 1 is a circuit diagram of a power supply device, which includes a DC-DC converter circuit 10 that converts a DC power supply voltage of a DC power supply 1 into a voltage level required by a load 2 and supplies the converted voltage level.

  The DC-DC converter circuit 10 includes a switching element 11 connected in series to the DC power supply 1 and a primary winding N1 (first inductance) of a transformer 12 that forms a closed circuit together with a series circuit of at least the DC power supply 1 and the switching element 11. Element), the smoothing capacitor 14 connected between both ends of the load 2 (load circuit), and the direction in which the current excited in the secondary winding N2 flows to the secondary winding N2 when the switching element 11 is turned off. A diode 13 as a first rectifier element connected in series (that is, a cathode connected to one end of the secondary winding N2), and a smoothing capacitor 14 between both ends of the series circuit of the secondary winding N2 and the diode 13 are connected. Connected between the resonance capacitor 15 connected to each other and the connection point between the capacitors 14 and 15 and the connection point between the secondary winding N2 and the diode 13. The secondary winding of the transformer 12 is turned on when the switching element 11 is turned on between both ends of a series circuit of the capacitors 14 and 15 and the inductor 16 (second inductance element) that forms a closed circuit with the secondary winding N2 and the resonant capacitor 15. And a diode 17 (second rectifier element) connected in a direction in which a current flows from the line N2. Note that the switching cycle and on-duty of the switching element 11 are controlled by the control circuit 41, and the drive circuit 42 drives the switching element 11 on / off based on a control signal input from the control circuit 41. Here, the control circuit 41 and the drive circuit 42 constitute a control unit that controls on / off of the switching element 11.

  2A and 2B are operation waveform diagrams of this circuit, in which FIG. 2A is an on / off state of the switching element 11, FIG. 2B is a current I1 flowing through the switching element 11, and FIG. (D) is the voltage V2 across the resonant capacitor 15, (e) is the secondary winding current I2 of the transformer 12, (f) is the current I3 flowing through the inductor 16, (d). (G) shows the current I4 flowing through the diode 13, respectively.

  In this DC-DC converter circuit 10, the primary winding N <b> 1 of the transformer 12 is connected between both ends of the DC power supply 1 via the switching element 11, and is switched by the drive circuit 12 in accordance with a control signal from the control circuit 41. In the state where the element 11 is turned on, a current flows from the DC power source 1 to the primary winding N1 of the transformer 12 and the switching element 11, and at this time, the number of turns of the power source voltage Vin is increased between both ends of the secondary winding N2 of the transformer 12. A voltage (Vin × n) multiplied by the ratio n is generated, and a current flows through the path of the secondary winding N 2 → the inductor 16 → the smoothing capacitor 14 and the load 2 → the diode 17 → the secondary winding N 2. Power is supplied. During this time, excitation energy is accumulated in the transformer 12 (period A in FIG. 2).

Thereafter, when the drive circuit 12 turns off the switching element 11 in accordance with the control signal of the control circuit 41, the excitation energy accumulated in the transformer 12 is changed from the secondary winding N2 → resonance capacitor 15 → smoothing capacitor 14 → diode 13 → second. It is discharged through the path of the next winding N2, and the resonant capacitor 15 and the smoothing capacitor 14 are charged (period B in FIG. 2).
When all the excitation energy accumulated in the transformer 12 is released, it is accumulated in the resonance capacitor 15 by a resonance operation by a closed circuit formed by the secondary winding N2 of the transformer 12, the resonance capacitor 15, and the inductor 16. As the energy is released, the current I2 flowing through the secondary winding N2 increases (period C in FIG. 2). In the middle of this period C, when the drive circuit 42 turns on the switching element 11 again by the control signal of the control circuit 41 (time t1), the superimposed voltage of the voltage excited in the secondary winding N2 and the voltage across the resonant capacitor 15 As a result, the secondary winding current I2 increases. This period C continues until the voltage V2 across the resonant capacitor 15 reaches a voltage of approximately the opposite polarity V3 across the smoothing capacitor 14, that is, until the combined voltage of the series circuit of the capacitors 14 and 15 becomes zero. Then, at time t2 when the combined voltage of the series circuit of the capacitors 14 and 15 becomes zero, the diode 17 is turned on and the operation returns to the period A described above.

Here, the capacitance of the resonance capacitor 15 is very small compared to the capacitance of the smoothing capacitor 14, and the inductance value L 1 of the secondary winding N 2 of the transformer 12 and the capacitance C 1 of the resonance capacitor 15. Is preferably set to a value that satisfies the relationship of the following expression (1) with respect to the switching period t _SW of the switching element 11.

  By setting the time constant defined by the inductance value L1 of the secondary winding N2 and the capacitance C1 of the resonant capacitor 15 and the switching period Tsw so as to satisfy the relationship of the above formula (1), the transformer 12 Can be quickly released to the capacitors 14 and 15 on the secondary side.

The time constant defined by the inductance value L2 of the inductor 16 and the electrostatic capacitance C1 of the resonant capacitor 15 also has the relationship of the following equation (2) with respect to the switching cycle t _SW of the switching element 11 as described above. It is preferable to set the value so as to satisfy.

By setting a time constant defined by the inductance value L2 of the inductor 16 and the capacitance C1 of the resonance capacitor 15 and the switching period t _SW so as to satisfy the relationship of the above equation (2), the resonance capacitor 15 It is possible to quickly increase the secondary winding current I2 by the stored energy and quickly shift to a period in which power can be supplied to the load 2 from the secondary side of the transformer 12 (period A in FIG. 2). Thus, the on-duty can be increased, and the efficiency can be improved by reducing the peak value of the circuit current.

  Further, after the secondary winding current I2 is rapidly increased as in the period C in FIG. 2 when the switching element 11 is turned on, the current I3 flowing through the inductor 16 continues to flow. Even when the voltage (input voltage Vin × turn ratio n) generated in the secondary winding N2 when the switching element 11 is on is lower than the output voltage, it is possible to extract power from the power source to the load side via the transformer 12. Thus, an output voltage higher than the voltage obtained by multiplying the turn ratio of the transformer 12 can be obtained while the basic operation is the forward converter.

The capacitance C2 of the smoothing capacitor 14 is preferably a value that satisfies the relationship of the following formulas (3) and (4), and is set to a predetermined value that provides a sufficient smoothing effect. The time constant Ta (= L1 × C2) defined by the capacitance C2 of the smoothing capacitor 14 and the inductance value L1 of the secondary winding N2 of the transformer 12, and the capacitance C2 of the smoothing capacitor 14 and the inductor 16 The time constant Tb (= L2 × C2) defined by the inductance value L2 is desirably set to a time that is at least 10 times the switching cycle _tSW .

  In this embodiment, the excitation energy of the transformer 12 is released not only to the resonance capacitor 15 but also to the smoothing capacitor 14 connected in series to the resonance capacitor 15, so that the voltage across the resonance capacitor 15 can be suppressed. become.

  The energy stored in the resonance capacitor 15 is released through a closed circuit formed by the resonance capacitor 15, the secondary winding N <b> 2 of the transformer 12 and the inductor 16, and the secondary winding is not passed through the smoothing capacitor 14. Since it is used for the operation of increasing the current I2, even when the voltage across the resonant capacitor 15 is lower than that in the conventional example shown in FIG. 11, it contributes to the increase of the secondary winding current I2 and obtains a boosting effect. The withstand voltage of the resonant capacitor 15 can be lowered.

  Furthermore, the excitation energy of the transformer 12 accumulated in the smoothing capacitor 14 is proportional to the output voltage when the capacitance of the smoothing capacitor 14 is sufficiently large, and the higher the output voltage, the more the smoothing capacitor 14 side than the resonance capacitor 15. Will be released. Therefore, when the power supply device of the present embodiment is used for a discharge lamp lighting device, the excitation energy of the transformer 12 is more accumulated on the smoothing capacitor 14 side as the output voltage becomes higher, such as a no-load voltage. The effect of suppressing the voltage across the capacitor 15 is further increased.

  Therefore, it is not necessary to use an element with high withstand voltage performance for the resonant capacitor 15 and the fluctuation range of the voltage across the terminals can be suppressed, so that the induction loss can be suppressed.

(Embodiment 2)
A second embodiment of the present invention will be described with reference to FIG. In the power supply device of this embodiment, in the power supply device of FIG. 1 described in the first embodiment, an inductor 12a is used instead of the transformer 12 as the first inductance element, and the switching element 11 and the DC are connected between both ends of the inductor 12a. A series circuit of the power source 1 is connected, a series circuit of an inductor 12a and a diode 13 is connected between both ends of the series circuit of the capacitors 14 and 15, and a closed circuit is formed by the inductor 12a, the inductor 16, and the resonant capacitor 15. ing. In addition, since it has the structure similar to the power supply device of Embodiment 1 except the point which used the inductor 12a, the same code | symbol is attached | subjected to a common component and the description is abbreviate | omitted.

  The DC-DC converter circuit 10 of the power supply apparatus has a step-down chopper configuration except for the inductor 12a and the resonant capacitor 15.

  The operation of this apparatus can be understood in the same manner as in the first embodiment. When the switching element 11 is turned on by the drive circuit 42 in response to a control signal from the control circuit 41, the switching element 11 is switched from the DC power source 1. Current flows through the inductor 12a through the inductor 12a and energy is stored in the inductor 12a. At the same time, current flows through the path of the DC power source 1 → the switching element 11 → the inductor 16 → the smoothing capacitor 14 and the load 2 → the diode 17 → the DC power source 1. Thus, power is supplied to the load 2 (period A).

Thereafter, when the drive circuit 42 turns off the switching element 11 according to the control signal of the control circuit 41, the excitation energy accumulated in the inductor 12a is the path of the inductor 12a → resonance capacitor 15 → smoothing capacitor 14 → diode 13 → inductor 12a. And the resonant capacitor 15 and the smoothing capacitor 14 are charged (period B).
When all of the excitation energy accumulated in the inductor 12a is released, the resonant operation by the closed circuit formed by the inductor 12a, the resonant capacitor 15, and the inductor 16 or the switching element 11 is turned on at this time. For example, the resonance operation by the closed circuit formed by the resonance capacitor 15 and the inductor 16 releases the energy stored in the resonance capacitor 15 and increases the current I3 flowing through the inductor 16 (period C). This period C continues until the voltage V2 across the resonant capacitor 15 reaches a voltage of approximately the opposite polarity V3 across the smoothing capacitor 14, that is, until the combined voltage of the series circuit of the capacitors 14 and 15 becomes zero. When the combined voltage of the series circuit of the capacitors 14 and 15 reaches zero, the diode 17 is turned on and the operation returns to the period A described above.

  As described above, the power supply device according to the present embodiment also uses the characteristics that the current I3 flowing through the inductor 16 is rapidly increased when the switching element 11 is turned on, and the current I3 of the inductor 16 continues to flow. Even when the output voltage is higher than the input voltage Vin, it is possible to extract power from the power source to the load side.

  In the present embodiment, the excitation energy of the inductor 12a is released not only to the resonance capacitor 15 but also to the smoothing capacitor 14 connected in series to the resonance capacitor 15, so that the voltage across the resonance capacitor 15 can be suppressed. become.

  Further, the energy stored in the resonance capacitor 15 is a closed circuit formed by the resonance capacitor 15, the inductor 12a and the inductor 16, or a closed circuit formed by the resonance capacitor 15 and the inductor 16 when the switching element 11 is turned on. Is used for the operation of increasing the current I3 of the inductor 16 without passing through the smoothing capacitor 14, so that even when the voltage across the resonant capacitor 15 is lower than that in the conventional example shown in FIG. The boosting effect can be obtained by contributing to the increase of the current I3.

  Further, the excitation energy of the inductor 12a accumulated in the smoothing capacitor 14 is proportional to the output voltage when the capacitance of the smoothing capacitor 14 is sufficiently large, and the higher the output voltage, the more the smoothing capacitor 14 side than the resonance capacitor 15 is. Will be released. Therefore, when the power supply device of this embodiment is used for a discharge lamp lighting device, the higher the output voltage, such as the no-load voltage, the more the excitation energy of the inductor 12a is accumulated on the smoothing capacitor 14 side. The effect of suppressing the voltage V2 across the capacitor 15 is further increased. Therefore, it is not necessary to use an element having a high withstand voltage performance for the resonant capacitor 15, and induction loss can be suppressed.

  In the present embodiment, when the inductance value of the inductor 12a (first inductance element) is L3, each constant is set to a value that satisfies the relationship of the following expressions (5) and (6). Preferably, the excitation energy of the inductor 12a is quickly discharged to the capacitors 14 and 15 on the secondary side, or the secondary winding current I2 is quickly increased by the energy stored in the resonance capacitor 15, so that the inductor 12a transfers to the load 2. It is possible to quickly shift to a period during which power can be supplied (period A), thereby increasing the on-duty, and improving efficiency by reducing the peak value of the circuit current. Can do.

(Embodiment 3)
Hereinafter, an embodiment of a discharge lamp lighting device using the power supply device described in the first embodiment will be described with reference to FIG. Since the configuration and operation of the DC-DC converter circuit 10 are the same as those of the first embodiment, common components are denoted by the same reference numerals and description thereof is omitted.

  The discharge lamp lighting device 20 according to the present embodiment includes a DC-DC converter circuit 10 that steps up and down the DC power supply voltage of the DC power supply 1 to a voltage necessary for lighting the discharge lamp 23 that is a load, and the high-intensity discharge lamp 23 that is turned off. And a full-bridge inverter circuit using switching elements S1 to S4. The output voltage of the DC-DC converter circuit 10 is converted into a rectangular wave alternating voltage and started. A rectangular wave inverter circuit 21 that is supplied to the high-intensity discharge lamp 23 via the circuit 22; a control circuit 41 that controls the output of the DC-DC converter circuit 10 by controlling the switching frequency, on-duty, etc. of the switching element 11; The driving circuit 4 that drives the switching element 11 on / off based on the control signal Sc input from the control circuit 41 It is equipped with a door.

  The control circuit 41 detects the output voltage Vout of the DC-DC converter circuit 10, detects the output current Iout using a current sensor, and based on the detection result and the power command to be supplied to the high-intensity discharge lamp 23. By performing feedback control, the output feedback control circuit 43 that outputs the on-time command signal Vref for adjusting the on-time of the switching element 11 and the on-time command signal Vref input from the output feedback control circuit 43 are turned on. And a control signal generation circuit 44 that outputs a control signal Sc having an adjusted width. The control signal generation circuit 44 includes a zero current detection circuit 44a, a monostable multivibrator 44b, a timer circuit 44c, and a flip-flop 44d.

  In the control signal generation circuit 44, the on-time command signal Vref from the output feedback control circuit 43 is input to the timer circuit 44c, and the passage of a predetermined on-time is measured in comparison with the charging time of the timer capacitor CT. Here, when a predetermined on-time determined by the on-time command signal Vref elapses, a reset signal is given from the timer circuit 44c to the reset terminal R of the flip-flop 44d, and the output signal of the flip-flop 44d as the control signal Sc is supplied. By switching to the L level, the switching element 11 is turned off.

  When the switching element 11 is turned off, the excitation energy stored in the transformer 12 is discharged from the secondary winding N2 through the diode 13 to the resonance capacitor 15 and the smoothing capacitor 14, and both capacitors 14 and 15 are charged.

  In the control circuit 41, since the switching element 11 has only to be turned on at a predetermined timing after the end of the release of the excitation energy stored in the transformer 12, the current I4 flowing through the diode 13 is detected using a current sensor such as a Hall IC. Then, zero current detection is performed by the zero current detection circuit 44a based on the detection result. That is, the zero current detection circuit 44a includes a comparator CP1 in which the output of the current sensor is input to the inverting input terminal. When the current I4 becomes smaller than a predetermined threshold, the output of the comparator CP1 becomes high, and the monostable multivibrator 44b. A pulse signal having a predetermined width is output as one pulse. At this time, the output signal (control signal Sc) of the flip-flop 44d is set to the H level, the switching element 11 is turned on by the drive circuit 42, and the switch RSW of the timer circuit 44c is turned on, so that the charge of the timer capacitor CT is increased. It is discharged (that is, the timer circuit 44c is reset and the on-time measurement is started). Thereafter, in the timer circuit 44c, when the timer capacitor CT is charged and the charge voltage exceeds the on-time command signal Vref, a signal is given from the timer circuit 44c to the reset input R of the flip-flop 44d, and the output signal of the flip-flop 44d (Control signal Sc) is reset to L level, and the switching element 11 is turned off by the drive circuit 42. As described above, since the flip-flop 44d outputs the control signal Sc having a pulse width corresponding to the voltage level of the on-time command signal Vref, the switching element 11 is turned on for a time width determined by the on-time command signal Vref. It is done. Here, as the ON time command signal Vref input from the output feedback control circuit 43 to the control signal generation circuit 44 increases, the ON time of the switching element 11 increases and the output voltage of the DC-DC converter circuit 10 increases.

  The discharge lamp lighting device is not intended to be limited to the circuit configuration described in the present embodiment. The feature of the present embodiment is that the re-on timing of the switching element 11 is determined based on the zero current of the current I4 of the diode 13. Therefore, as long as such an operation can be realized, the circuit configuration of the control circuit 41, the on-time adjustment method, or the output control means are not limited to this embodiment.

  Further, the zero current detection of the current I4 of the diode 13 is not limited to the configuration of the present embodiment, but the zero current is detected based on the voltage across the diode 13 in addition to the one that directly detects the current. Also good. In this case, if the voltage across the diode 13 is substantially zero, it is determined that the diode 13 is turned on and a current is flowing. Under other conditions, the diode 13 is turned off and the current I4 of the diode 13 is zero. What is necessary is just to judge that it is, and what detects a zero electric current indirectly may be sufficient. When the voltage across the diode 13 is detected, an increase in the voltage across the diode 13 when the diode 13 is turned off can be detected with high sensitivity using a signal that has passed through a differentiating circuit such as a CR pseudo-differential circuit.

  In the present embodiment, it goes without saying that the DC-DC converter circuit 10 described in the second embodiment may be used instead of the DC-DC converter circuit 10 described in the first embodiment.

(Embodiment 4)
Hereinafter, an embodiment of a discharge lamp lighting device using the power supply device described in the first embodiment will be described with reference to FIG. Since the configuration other than the control circuit 41 is the same as that of the third embodiment, the common components are denoted by the same reference numerals and the description thereof is omitted.

  In the third embodiment, the zero current of the current I4 flowing through the diode 13 is detected and the switching element 11 is turned on again. In the present embodiment, the inflection point of the both-ends voltage (V2 + V3) of the capacitors 14 and 15 is detected. An inflection point detection circuit 44e is provided, and when the inflection point is detected, the switching element 11 is turned on again.

  The operation of this apparatus will be described below. About the ON time of the switching element 11, since the operation | movement similar to the discharge lamp lighting device of Embodiment 3 is performed, the description is abbreviate | omitted.

  When the switching element 11 is turned off, the excitation energy stored in the transformer 12 is discharged from the secondary winding N2 through the diode 13 to the resonance capacitor 15 and the smoothing capacitor 14, and both capacitors 14 and 15 are charged.

  In the control circuit 41, since the switching element 11 may be turned on again at a predetermined timing after the end of the discharge of the excitation energy stored in the transformer 12, in the present embodiment, the end of the discharge of the excitation energy is set to the secondary side capacitor 14, Judged from 15 voltage waveforms. That is, after the switching element 11 is turned off, the voltage (V2 + V3) across the series circuit of the secondary side capacitors 14 and 15 rises in a sine wave shape, and when the excitation energy release ends, the inflection point of the sine waveform ( In other words, this corresponds to the time when the slope of the sine waveform switches from positive to negative.

  Therefore, in this embodiment, the inflection point detection circuit 44a detects the voltage (V2 + V3) across the series circuit of the capacitors 14 and 15, and the detected voltage is applied to the differentiation circuit 45 configured by, for example, a CR pseudo-differentiation circuit. You are typing. When the comparator CP1 detects that the voltage across the series circuit of the capacitors 14 and 15 has reached the inflection point and the output level of the differentiating circuit 45 has changed from positive to negative, a pulse having a predetermined width is output from the monostable multivibrator 44b. The signal is output by one pulse. At this time, the output signal (control signal Sc) of the flip-flop 44d is set to the H level, the switching element 11 is turned on by the drive circuit 42, and the switch RSW of the timer circuit 44c is turned on, so that the charge of the timer capacitor CT is increased. It is discharged (that is, the timer circuit 44c is reset and the on-time measurement is started). Thereafter, in the timer circuit 44c, when the timer capacitor CT is charged and the charge voltage exceeds the on-time command signal Vref, a signal is given from the timer circuit 44c to the reset input R of the flip-flop 44d, and the output signal of the flip-flop 44d (Control signal Sc) is reset to L level, and the drive circuit switching element 11 is turned off. As described above, since the flip-flop 44d outputs the control signal Sc having a pulse width corresponding to the voltage level of the on-time command signal Vref, the switching element 11 is turned on for a time width determined by the on-time command signal Vref. It is done. As the on-time command signal Vref input from the output feedback control circuit 43 to the control signal generation circuit 44 increases, the on-time of the switching element 11 increases and the output voltage of the DC-DC converter circuit 10 increases. It has become.

  Here, in this embodiment, the end of excitation energy release is detected by detecting the voltage (V2 + V3) across the series circuit of the capacitors 14 and 15 by the inflection point detection circuit 44a. Since the voltage V3 is relatively stable when viewed at the switching frequency level and has little influence on the detection of the inflection point, the inflection point may be detected only from the voltage V2 across the resonance capacitor 15. For example, when the ground level on the secondary side of the transformer 12 is provided at the connection point between the smoothing capacitor 14 and the resonance capacitor 15, it is more resonant than detecting the voltage (V2 + V3) across the series circuit of the capacitors 14 and 15. Detection is easier when only the voltage V2 across the capacitor 15 is detected.

  Note that the discharge lamp lighting device is not limited to the circuit configuration described in the present embodiment, and the feature of the present embodiment is that the capacitors 14 and 15 provided on the secondary side of the transformer 12 are connected to the transformer 12. Since the point in time at which the excitation energy has been released is obtained by detecting the inflection point of the voltage waveform of the capacitor and the re-on timing of the switching element 11 is determined based on this detection result, such an operation is performed. As long as it can be realized, the circuit configuration of the control circuit 41, the on-time adjustment method, and the output control means are not limited to the present embodiment.

  In the present embodiment, it goes without saying that the DC-DC converter circuit 10 described in the second embodiment may be used instead of the DC-DC converter circuit 10 described in the first embodiment.

(Embodiment 5)
Below, embodiment of the discharge lamp lighting device using the power supply device demonstrated in Embodiment 1 is described based on FIG. Since the configuration other than the control circuit 41 is the same as that of the third embodiment, the common components are denoted by the same reference numerals and the description thereof is omitted.

  In the third embodiment, the zero current of the current I4 flowing through the diode 13 is detected and the switching element 11 is turned on again. In this embodiment, the excitation energy is completely released from the voltage generated in the transformer 12. When the end of the excitation energy release is detected, the switching element 11 is turned on again.

  The operation of this apparatus will be described below. About the ON time of the switching element 11, since the operation | movement similar to the discharge lamp lighting device of Embodiment 3 is performed, the description is abbreviate | omitted.

  When the switching element 11 is turned off by the drive circuit 42, the excitation energy stored in the transformer 12 is discharged from the secondary winding N2 to the resonance capacitor 15 and the smoothing capacitor 14 via the diode 13, and both capacitors 14, 15 Is charged.

  In the control circuit 41, the switching element 11 may be turned on again at a predetermined timing after the end of the discharge of the excitation energy stored in the transformer 12, so in this embodiment, the voltage generated at the end of the discharge of the excitation energy in the transformer 12 Judging from. That is, after the switching element 11 is turned off, the diode 13 is turned on while the excitation energy emission current of the transformer 12 is flowing, so that the capacitors 14 and 15 are placed between both ends of the secondary winding N2 of the transformer 12. A voltage substantially equal to the voltage across the series circuit is applied, and the voltage waveform rises in a sine wave shape. When the diode 13 is turned off after the excitation energy of the transformer 12 has been released, only the voltage V2 across the resonant capacitor 15 is divided by the secondary winding N2 and the inductor 16, and the voltage is applied to the secondary winding N2. Since it is applied, the voltage applied to the secondary winding N2 will drop rapidly. Therefore, in this embodiment, the end of excitation energy discharge is detected by detecting this inflection point with the diode-off detection circuit 44f.

  That is, in this embodiment, the tertiary winding N3 provided in the transformer 12 is used, and the voltage generated in the transformer 12 is detected from the voltage across the tertiary winding N3. The inflection point (that is, the end of the excitation energy release) may be detected by inputting the detection voltage of the tertiary winding to the differentiation circuit as described in the fourth embodiment. The point in time when the emission is finished does not completely coincide with the timing when the diode 13 is turned off. This is because the current I3 flows through the inductor 16 even when the excitation energy has been released, as shown in FIG. However, since it is more advantageous in terms of circuit efficiency to turn the switching element 11 on again after the diode 13 is turned off, in this embodiment, the off time of the diode 13 is detected from the voltage of the tertiary winding N3. Yes.

  Here, when the diode 13 is turned off, only the voltage V2 of the resonance capacitor 15 is divided by the secondary winding N2 and the inductor 16, and is applied to the secondary winding N2, so that the voltage across the secondary winding N2 is increased. Will drop rapidly, but at this time, ringing occurs when the voltage across the secondary winding N2 drops due to the influence of the stray capacitance Cp of the transformer 12, the junction capacitance of the diode, the parasitic capacitance of the circuit pattern, the parasitic inductance, etc. Occurs. That is, since the voltage across the secondary winding N2 instantaneously drops to below zero or near zero, the diode OFF detection circuit 44f detects the voltage drop of the tertiary winding N3 provided on the secondary side by the comparator CP1. Then, it is detected as the off timing (zero current) of the diode 13. When the diode OFF detection circuit 44f detects the OFF time of the diode 13, the output of the comparator CP1 is inverted to H level, so that a pulse signal having a predetermined width is output from the monostable multivibrator 44b. At this time, the output signal (control signal Sc) of the flip-flop 44d is set to the H level, the switching element 11 is turned on by the drive circuit 42, and the switch RSW of the timer circuit 44c is turned on, so that the charge of the timer capacitor CT is increased. It is discharged (that is, the timer circuit 44c is reset and the on-time measurement is started). Thereafter, in the timer circuit 44c, when the timer capacitor CT is charged and the charge voltage exceeds the on-time command signal Vref, a signal is given from the timer circuit 44c to the reset input R of the flip-flop 44d, and the output signal of the flip-flop 44d (Control signal Sc) is reset to L level, and switching element 11 is turned off by drive circuit 42. As described above, since the flip-flop 44d outputs the control signal Sc having a pulse width corresponding to the voltage level of the on-time command signal Vref, the switching element 11 is turned on for a time width determined by the on-time command signal Vref. It is done. Here, as the ON time command signal Vref input from the output feedback control circuit 43 to the control signal generation circuit 44 increases, the ON time of the switching element 11 increases and the output voltage of the DC-DC converter circuit 10 increases. It has become.

  Note that the discharge lamp lighting device is not limited to the circuit configuration described in the present embodiment, and the feature of the present embodiment is that the inflection point of the secondary winding voltage when the switching element 11 is off, or Since the voltage drop of the secondary winding voltage in consideration of the ringing voltage due to the diode 13 being turned off is detected and the re-on timing of the switching element 11 is determined based on the detection result, such an operation is realized. If possible, the circuit configuration of the control circuit 41, the on-time adjustment method, or the output control means are not limited to this embodiment. In the present embodiment, the secondary winding voltage is indirectly detected to use the tertiary winding N3 provided on the secondary side of the transformer 12. However, the secondary winding is directly detected. Alternatively, it may be detected indirectly using the primary winding voltage.

  In the present embodiment, it goes without saying that the DC-DC converter circuit 10 described in the second embodiment may be used instead of the DC-DC converter circuit 10 described in the first embodiment.

(Embodiment 6)
Hereinafter, an embodiment in which the discharge lamp lighting device using the power supply device described in each of the above embodiments is applied to a vehicle headlamp device will be described with reference to FIGS. 7 and 8. FIG. 7 is a schematic configuration diagram of the vehicle headlamp device of the present embodiment, and FIG. 8 is an external perspective view of a vehicle using the vehicle headlamp device of the present embodiment.

  This vehicle headlamp device 50 has a substantially box-shaped lamp 51 having an open front surface, and a socket 53 for mounting the discharge lamp 23 inside the lamp 51 using appropriate means (not shown). The discharge lamp lighting device 20 fixed to the lower surface of the lamp 51 and the socket 53 are electrically connected via a lamp line 55. Inside the lamp 51, a reflecting mirror 54 that reflects the light of the discharge lamp 23 forward and a light-shielding plate 56 for preventing glare are attached using appropriate attachment means (not shown). The emitted light 23 is irradiated to the outside through a translucent cover 52 attached to the opening of the lamp 51.

  The discharge lamp lighting device 20 is configured by housing a circuit board (not shown) on which the circuits described in the above embodiments are formed in a case 20a attached to the lower side of the lamp 51, The discharge lamp lighting device 20 is supplied with a DC power supply voltage from a DC power supply 1 made of an in-vehicle battery via a lighting switch SW and a fuse F.

  Such a vehicle headlamp device 50 is attached to the left and right sides of the front side of the vehicle body 60 as shown in FIG. 8, and the discharge lamp lighting device using the power supply device described in the first to fifth embodiments. Therefore, the vehicle headlamp device 50 using the discharge lamp lighting device that can reduce inductive loss without increasing the size and cost can be realized, and the vehicle headlamp device can be realized. 50 can be reduced in size, so that a vehicle that does not require a large space for mounting the vehicle headlamp device 50 can be realized.

  By the way, as a high-intensity discharge lamp 23 for a vehicle, a metal halide lamp that does not contain mercury has been developed, but in general, the lamp voltage during steady lighting is about half lower than that of a lamp containing mercury. Yes. On the other hand, the no-load voltage cannot be reduced much in terms of starting performance, so the difference between the load voltage during steady lighting (lamp voltage) and the no-load voltage during extinguishing is greater than for lamps containing mercury. As described in the above embodiments, the power supply device according to the present invention can obtain a high step-up ratio without causing an increase in size and cost of the device, so that such a load (metal halide not containing mercury) can be obtained. It is suitable as a circuit for lighting a lamp.

  It should be noted that a wide variety of different embodiments can be configured without departing from the spirit and scope of the present invention, and the present invention is not limited to a specific embodiment.

1 is a circuit diagram of a power supply device according to a first embodiment. (A)-(g) is a wave form diagram of each part explaining operation | movement same as the above. FIG. 6 is a circuit diagram of a power supply device according to a second embodiment. It is a circuit diagram of the discharge lamp lighting device of Embodiment 3. It is a circuit diagram of the discharge lamp lighting device of Embodiment 4. It is a circuit diagram of the discharge lamp lighting device of Embodiment 5. It is a schematic block diagram of the vehicle headlamp apparatus of Embodiment 6. It is an external appearance perspective view of the vehicle using the same as the above. It is a circuit diagram of the discharge lamp lighting device using the conventional power supply device. (A)-(c) is a wave form diagram explaining the operation | movement same as the above. It is a circuit diagram of the other conventional power supply device.

Explanation of symbols

1 DC power supply 2 Load (load circuit)
10 DC-DC converter circuit (power supply)
11 Switching element 12 Transformer (first inductance element)
13 Diode (first rectifier)
14 Smoothing capacitor 15 Resonance capacitor 16 Inductor (second inductance element)
17 Diode (second rectifier)
41 Control circuit (control unit)
42 Drive circuit N1 Primary winding N2 Secondary winding

Claims (8)

  A closed circuit comprising at least a DC power supply, a switching element and a first inductance element; a control unit for controlling on / off of the switching element; a smoothing capacitor connected between both ends of the load circuit; A first rectifier element connected in series with the first inductance element in a direction in which a current excited in the one inductance element flows, and at least between both ends of the series circuit of the first inductance element and the first rectifier element A resonance capacitor connected to the first capacitor through a smoothing capacitor; and a connection point between the two capacitors and a connection point between the first inductance element and the first rectifier element; And a second inductance element forming a closed circuit together with both ends of the series circuit of the two capacitors. The power supply apparatus characterized by comprising a second rectifying element connected in the direction of current flows from the first inductor element when the switching element.   The first inductance element includes a transformer in which a primary winding forms a closed circuit together with at least a DC power source and a switching element, and a secondary winding is connected in series with the first rectifier element. A series circuit of the two capacitors is connected between both ends of the series circuit of the winding and the first rectifying element, and the secondary winding forms a closed circuit together with the second inductance element and the resonant capacitor. The power supply device according to claim 1. In the first inductance element, the inductance value of the inductance component that forms a closed circuit together with the second inductance element and the resonance capacitor is L1, the inductance value of the second inductance element is L2, the capacitance of the resonance capacitor is C1, and switching When the switching period of the element is t _SW ,

The power supply device according to claim 1, wherein:   The energy stored in the first inductance element when the switching element is turned on is released to the series circuit of both capacitors when the switching element is turned off, and the control unit releases the energy stored in the first inductance element. The power supply device according to any one of claims 1 to 3, wherein the switching element is not turned on again until it is finished.   A discharge lamp lighting device comprising: a load circuit including at least a discharge lamp as a load; and the power supply device according to any one of claims 1 to 4 that supplies power to the load circuit.   6. The discharge lamp lighting device according to claim 5, wherein the discharge lamp is a metal halide lamp containing no mercury.   A vehicle headlamp device comprising the discharge lamp lighting device according to claim 6.   A vehicle comprising the vehicle headlamp device according to claim 7.

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