JP3331713B2 - Power supply - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a power supply device for converting a DC power supply into a rectangular wave using a switching element.

[0002]

2. Description of the Related Art When a discharge lamp is lit with a low-frequency rectangular wave current, when a polarity of a bridge type inverter circuit is reversed while a current of a predetermined value or more is flowing through the discharge lamp at the time of starting, a pulse transformer is turned on. There is a problem that resonance occurs between the inductance element on the secondary side and the smoothing capacitor in the power supply circuit unit, and the voltage of the smoothing capacitor rises significantly above an allowable value. In order to suppress this voltage rise, for example, by applying the effect of JP-A-3-116669, the PWM is synchronized with the polarity inversion of the bridge type inverter circuit.
It is conceivable to reduce the current supplied from the controlling chopper circuit. By performing such control, the current supplied to the load circuit connected to the bridge-type inverter circuit gradually changes and is inverted, so that the voltage increase due to resonance as described above can be suppressed. is there.

[0003]

However, in the above-described control system, there is a problem that a circuit for controlling the chopper is complicated, and there is a possibility that a delay occurs in power supply from the chopper. . The present invention does not require the above-described complicated control, and maintains the power supply to the load under the control of the chopper unit or the inverter circuit unit at a constant level. It is an object of the present invention to provide a power supply device capable of suppressing an increase in voltage of the power supply.

[0004]

According to the power supply device of the present invention, as shown in FIG. 1, a DC power supply E and a DC / DC connected to the DC power supply E are provided to solve the above-mentioned problems.
Converter circuit unit 1 and DC / DC converter circuit unit 1
, A bridge-type inverter circuit unit 2 for converting the voltage of the capacitor C into a rectangular wave voltage, and an inductance element L connected to the output of the inverter circuit unit 2. In a power supply device comprising a load circuit 3 in which a load Z is connected in series,
When a current equal to or more than a predetermined value flows, for example, at the time of starting the discharge lamp, the inductance value of the inductance element L is reduced for a certain period at least immediately before the polarity of the output current of the inverter circuit unit 2 is inverted. This suppresses the resonance voltage caused by the inductance element L and the smoothing capacitor C, and suppresses an increase in the voltage Vc. Indak
Means for reducing the inductance value of the
For example, as shown in FIG.
Or the inductance element as shown in FIG.
Use the switch SW ₁ for reducing the inductance value
Good to be. Another means to solve the same problem
To eliminate the energy generated in the inductance element L.
(Figs. 12 and 15) or return to the power supply side (Fig. 1
3, FIG. 16).

[0005]

Operation In the circuit of FIG.
DC / DC converter circuit 1
Capacitor C and inductance connected to the output of
Voltage of capacitor C generated by resonance voltage with element L
Vc rises by √ (LI ^Two/ C) and the load current
When I is large, the voltage Vc of the capacitor C becomes large.
Become. When a large current of a predetermined value or more flows through the load Z
When the polarity of the output current of the inverter circuit unit 2 is inverted.
At least for a certain period immediately before
By reducing the conductance value,
Resonance energy can be reduced
The rise of the voltage Vc of C can be suppressed low.

FIG. 2 shows waveforms of the voltage Vc of the capacitor C and the current Iz flowing through the load Z in FIG. FIG. 3 is a partially enlarged view of FIG. FIGS. 2 and 3 show a case where a saturable inductance is used as the variable inductance element L, a discharge lamp is used as the load Z, and the magnetic saturation occurs when a current of a predetermined value or more flows through the load Z. 4 shows operation waveforms. For example, at the time of starting the discharge lamp, when the current of 2 to 3 times the discharge lamp rating flows, the setting is made such that the inductance value of the secondary side of the pulse transformer of the igniter section is automatically reduced by magnetic saturation. In other words, no control circuit is required and the capacitor C
Of the voltage Vc can be suppressed. The solid line in FIG. 3 shows a waveform when the inductance value of the inductance element L is reduced before the polarity of the output current of the inverter circuit unit 2 is inverted. At this time, the saturable inductance is magnetically saturated. The dotted line shows the waveform of the voltage Vc of the capacitor C and the current Iz of the discharge lamp when the inductance value of the inductance element L is not changed.

As is apparent from FIG. 3, when the inductance value of the inductance element L is decreased at least immediately before the polarity reversal of the output current of the inverter circuit section 2, the lamp current has a change in slope due to a change in the inductance value. When the saturable inductance element is used for the change of the inductance element L due to saturation / unsaturation), two points a
And c. At the point b, the polarity of the lamp current I of the discharge lamp is reversed. In a portion where the value of the inductance element L is large, the slope of the change in the lamp current I of the discharge lamp is gentle, and the slope of the lamp current I when the inductance element L is small is steep. The maximum voltage Vp of the smoothing capacitor C when the inductance element L is not changed
₁ and the maximum value Vp ₂ when the inductance value of the inductance element L is changed, Vp ₁ > Vp
and it has a p _2.

[0008]

FIG. 4 is a circuit diagram of a first embodiment of the present invention.
In this embodiment, the output of the inverter circuit unit 2 at the time of starting is
FIG. 5 shows operation waveforms when the polarity is inverted. This implementation
In the example, as the DC / DC converter circuit unit 1, step-up / step-down
Uses a chopper circuit. Buck-boost chopper circuit
Then, the switching element Q that operates at high frequency₁On time
Is controlled by PWM to control the output voltage. Smoothing
Capacitor C₁Smoothes the output voltage of the buck-boost chopper circuit
Then, the DC voltage Vc₁Is supplying
You. Inverter circuit 2 has four switching
Element Q_Two~ Q _FiveFull-bridge type inverter circuit using
I use the road. Switching of the inverter circuit 2
Element Q_Two, Q_FiveAnd Q_Three, Q_FourAlternately on and off at low frequency.
The square wave current is supplied to the load by operating the load. negative
The inductance element L connected in series with the load
Use a pulse transformer as the sum-type inductance.
A discharge lamp Z is connected as a load in series. Load times
When the discharge lamp Z is started, the saturable inductance of the road
A lamp current exceeding a predetermined value (for example, two to three times the rating)
When it is magnetically saturated.

Hereinafter, the operation when the output polarity of the inverter circuit section 2 is inverted will be described. When the output polarity of the inverter circuit 2 is inverted, the charge current flowing through the resonance in the smoothing capacitor C _1, including the dead time in switching, the capacitor C ₁ in FIG. 4, the transistors Q ₅ and the diode D _5, Inductor L, discharge lamp Z,
Transistor Q ₂ and the diode D _2, through a path of the capacitor C _1. At the start, when a predetermined value or more of the lamp current is flowing, because the inductance element L is saturated, the inductance value is small, the output polarity in this state is inverted, the voltage V of the capacitor C ₁
increase of c ₁ is kept low.

In FIG. 5, during the period from t _{0 to} ta, the inductance value L is small because the inductance element L is saturated. The switching element Q ₂ to Q ₅ of the inverter circuit 2 is polarity inverted in this state, the lamp current decreases, at time ta, the inductance element at a certain current value becomes non-saturated, the inductance value decreases . From this time, the gradient of the change in the lamp current becomes gentle for a certain period. During the period from ta to tc, the inductance element is in a non-saturated state. When the polarity of the lamp current is inverted and becomes greater than or equal to a predetermined current value, the inductance element is saturated again, the slope of the lamp current becomes steep, and rises to the predetermined current value. This is the operation of a period of tc~t _2. As described above, in the present embodiment, when the polarity of the inverter circuit unit 2 is inverted, a change in the slope of the lamp current (a change due to saturation / unsaturation of the inductance element) is observed at two points. In the present embodiment, the increase in the resonance voltage Vc ₁ due to the inductance element L and the capacitor C ₁ at the time of starting can be suppressed only by using only the magnetic saturation of the inductance element L, and the switching element Q _{1 of the} chopper section is used.
Since no control is required at all, the control circuit can be simplified.

FIG. 6 is a circuit diagram of a second embodiment of the present invention.
You. In this embodiment, the inverter circuit 2
FIG. 7 shows operation waveforms when the output polarity is inverted. Book
In the embodiment, an AC power supply AC is used as an input power supply.
Rectifier / smoothing circuit consisting of bridge DB and capacitor Co
The DC voltage converted by step 4 is used.
A power supply may be used. DC / DC converter circuit 1
Have inductors La and Lb and switching element Q₁Passing
And diode D₁Using a boost chopper circuit with
And the output voltage is equal to the smoothing capacitor C₁Charged
It is. The inverter circuit section 2 has a full-bridge type
A barter circuit is used. Load circuit inductance
The element L is a saturated element connected to the igniter IGT.
Using a Japanese type pulse transformer, load Z (discharge
Electric light) and bypass to supply pulse current
Capacitor C_TwoAre inserted in parallel. Where
Densa C_TwoThe capacity of the capacitor C₁Enough compared to the capacity of
Is set to small. The output of the inverter circuit 2 and
Inductance element L consisting of a choke coil in series ₁
Is inserted.

In this embodiment, the inverter circuit 2
Switching element Q_Two, Q_FiveAnd Q_Three, Q_FourIn two modes
It works with. Switching element Q_Two, Q_FiveWhen
Q_Three, Q _FourIs turned on and off alternately at low frequency,
The switching operation is performed at a high frequency.
Supply to discharge lamp by PWM control of time pulse width
Power to be determined. This allows the load to have a square wave
Supplying current. Load circuit saturable pulse transformer
When no load is applied, the PT generates a high-voltage pulse and starts the discharge lamp.
During operation, a current equal to or greater than a predetermined value (for example, a rated current of 2 to 3
When the current is twice as high, magnetic saturation occurs.
The inductance value decreases, and the lamp
Acts as a low-pass filter for current.

The voltage Vc ₁ of the capacitor C ₁ in FIG.
The operation waveforms of the lamp current and the lamp current are the same as those in the previous embodiment. As in this embodiment, even in the case of PWM control the switching elements of the inverter circuit 2, it is possible to suppress the increase of the voltage Vc ₁ of the capacitor C ₁ caused by the inverting resonant at the output polarity of the inverter circuit 2 .

FIG. 8 is a circuit diagram of a third embodiment of the present invention. FIG. 9 shows operation waveforms when the output polarity of the inverter circuit unit 2 is inverted at the time of startup in this embodiment. D
As C / DC converter circuit 1, the transistor Q _11, Q ₁₂ and transformer T ₂ and diodes D _11, D consisting of ₁₂ push-pull converter circuit is used. The voltage output from the converter circuit is smoothed by the smoothing capacitor C ₁ and input to the inverter circuit unit 2. As the inverter circuit section 2, a capacitor C
_3, using a half-bridge type inverter circuit using C ₄ and transistors Q _4, Q _5. The inductance of the load circuit includes the pulse transformer PT in the igniter section.
Is used. In this embodiment, the switch S
By W _1, it is to be able to reduce the inductance value. The load Z is a discharge lamp, and the load Z
Is connected to the next winding and in series, further insert the capacitor C ₂ of the pulse current bypass in parallel. Capacitance of the capacitor C ₂ is very smaller than the capacitance of the capacitor C _1. It is inserted choke coil as an inductance L ₁ to the output of the inverter circuit 2. Is is a lamp current detection unit that detects the magnitude of the lamp current. The detected lamp current is compared with the reference voltage Vk by the comparison circuit 5. As a result, the state of the polarity inversion is detected, and the output of the comparison circuit 5 is input to the NAND circuit 8 together with the output of the low-frequency oscillator 7 via the NOT circuit 6, and the output thereof is switched via the drive circuit 9. SW1
Drive.

In the push-pull type converter circuit section 1, power to be supplied to the discharge lamp is determined by performing PWM control on the ON time of the switching elements Q ₁₁ and Q _{12 which} operate at a high frequency. The present invention can also be applied to a case where the switching elements Q ₄ and Q ₅ of the inverter circuit unit 2 are supplied with power by PWM control. In the inverter circuit 2 of the half-bridge, to switch the switching operation of the switching element Q ₄ and Q ₅ in a low frequency, the switching element Q ₄ and Q ₅ in the switching operation by the high-frequency operation, a rectangular wave to the discharge lamp Supplying current.

[0016] In this embodiment, the predetermined period switch SW ₁ from the polarity inversion time immediately before the output current of the inverter circuit 2 at the time of startup by turning on state, a short circuit part of the secondary inductance of the pulse transformer PT And reduce the inductance value. In this way, inductance with a small state, the welcome at the time of reversal of polarity of the inverter output, increase of the voltage Vc ₁ due to the resonance of the capacitor C ₁ that occurs at this time can be kept low.

[0017] Here, a description will be given of the control example of the switch SW _1. The lamp current detection section Is is connected to the output of the bridge type inverter circuit section 2, and the output voltage thereof is compared with a reference voltage Vk. The reference voltage Vk is set so that the output of the comparison circuit 5 is set to a low level when a current, for example, two to three times the discharge lamp rating flows. When a predetermined value or more current flows at the time of the discharge lamp starting, the output of the NOT circuit 6 is High level, the output from the low frequency oscillator 7 becomes High level, the switch SW ₁ to the ON state. When the output from the low frequency oscillator 7 is Low level, the switch SW ₁ is turned off. The output voltage waveform (frequency f) of the inverter circuit section 2 and the low-frequency oscillator 7
FIG. 10 shows the output voltage waveform (frequency 2f). Immediately before the polarity of the output current of the inverter circuit unit 2 is inverted, the output voltage of the low-frequency oscillator 7 becomes High level.
The output of the low frequency oscillator 7 is set.

Next, the operation waveform of FIG. 9 will be described.
switch SW ₁ is turned on at t = t _1, in a state where the inductance value of the secondary side of the pulse transformer PT is decreased, the polarity of the switching element Q _4, Q ₅ is inverted at t = t _2, the lamp current Iz Changes rapidly. When the switch SW ₁ at t = tb has elapsed a period of time is turned off, the inductance value increases, the change in the lamp current Is becomes gentle. Therefore, a change in the slope of the lamp current is observed at the point b. Voltage V of the capacitor C ₁
The change in c ₁ is in accordance with the change in the lamp current Iz. The pulse transformer PT has a saturable type,
The limitation of the unsaturated type is not particularly required.

FIG. 11 is a circuit diagram of a fourth embodiment of the present invention. The difference from the other embodiments is that the DC power supply V ₁ is connected to the tertiary side of the pulse transformer (PT) of the load circuit via the switch SW ₁ , and the DC power supply V ₁ is reversed via the switch SW _2. is that connecting the DC power supply V ₂ of polarity. The polarity of the transformer PT is set as shown in the figure. When the lamp current Iz flows in the direction shown in FIG.
_{When 1} is turned on and a current flows through the primary side of the pulse transformer PT, the inductance value on the secondary side of the pulse transformer PT decreases. When the lamp current Iz flows in the opposite direction to FIG. 11, by turning on the switch SW _2, it is possible to reduce the inductance value of the secondary side of the pulse transformer PT. At the start, based on the direction of flow from immediately before the inversion of the output polarity of the inverter circuit 2 of the lamp current, a period of time, reducing the secondary inductance of the pulse transformer PT and the switch SW ₁ or SW ₂ to the ON state Then, this inductance value and the capacitor C ₁
Increase in the voltage Vc ₁ due to the resonance of.
The control example of the switch SW ₁ and SW ₂ may be, for example, applications such as control of the third embodiment. In addition,
In this embodiment, by performing power control by the PWM control by the switching element to Q ₁ the converter circuit section 1.

FIG. 12 is a circuit diagram of a fifth embodiment of the present invention. Differs from the other embodiments, through the switch SW ₁ on the tertiary side of the pulse transformer PT of the load circuit is that the resistor R ₁ is provided with a closed loop circuit connected. At the start, and from immediately before the inversion of the output polarity of the inverter circuit 2 to turn on the switch SW _1, upon reversal of the output polarity of the inverter circuit 2, caused by the inductance and the capacitor C ₁ of the secondary side of the pulse transformer PT resonance to consume the energy in the resistor R _1. Now, the capacitor C
It is possible to suppress ₁ of a rise in the voltage Vc _1. The control example of the switch SW ₁ may be, for example, applying the control of the third embodiment. Incidentally, in this embodiment, it performs the power control by the PWM control by the switching element to Q ₁ the converter circuit section 1.

FIG. 13 is a circuit diagram of a sixth embodiment of the present invention. The difference from the embodiment of FIG.
That is, the resonance energy generated when the output polarity is inverted is fed back to the power supply circuit side. At the start, a period of time from immediately before the inversion of the output polarity of the inverter circuit 2, by turning on the switch SW _1, through the rectifier circuit DB resonance energy generated during the polarity reversal from the tertiary side of the pulse transformer PT, the power supply side for example is fed back to the example, a drive power source of the switching element Q _1. By doing so, on which it is possible to suppress the increase of the voltage Vc ₁ of the capacitor C _1, it is also improved overall efficiency of the circuit. The control example of the switch SW ₁ may be, for example, applying the control of the third embodiment.

FIG. 14 is a circuit diagram of a seventh embodiment of the present invention. The difference from the fourth embodiment, the load circuit is that connecting the secondary inductance L ₁ of another transformer inductance in series with the secondary side of the pulse transformer PT. The polarity of this transformer is set in the direction shown in the figure.
The operation of the direction switch SW ₁ and SW ₂ of the lamp current, the same as the fourth embodiment described above. A secondary inductance L _{1 of} a transformer different from the pulse transformer PT
The, from immediately before the inversion of the output polarity of the inverter circuit 2 by making a certain period decreases at starting, it is possible to suppress the increase of the voltage Vc ₁ of the capacitor C ₁ due to the resonance during polarity reversal. In the present embodiment, by providing a variable inductance different from the pulse transformer PT, the configuration of the pulse transformer PT can be simplified as compared with the other embodiments in which a tertiary winding is installed in the pulse transformer PT.

FIG. 15 is a circuit diagram of an eighth embodiment of the present invention. The difference from the fifth embodiment is that connecting the inductance L ₁ by pulse transformer secondary winding in series with the primary winding of the transformer to a load circuit. The switch SW ₁ from immediately before the inversion of the output polarity of the inverter circuit 2 by a certain period of time on state at the start, to consume the resonance energy generated during the polarity reversal at the secondary side of the transformer a resistor R _1. Thus, it is possible to suppress the increase of the voltage Vc ₁ of the capacitor C _1. In this embodiment, the structure of the pulse transformer can be simplified as compared with other embodiments in which a tertiary winding is provided in the pulse transformer. In addition,
Capacitor C ₃ is a capacitor for low-pass filtering of the lamp current.

FIG. 16 is a circuit diagram of a ninth embodiment of the present invention. The difference from the sixth embodiment, the load circuit is that connecting the inductance L ₁ by the secondary winding and the primary winding of the transformer in series of the pulse transformer PT. The switch SW ₁ from immediately before the inversion of the output polarity of the inverter circuit 2 by making a predetermined period on at the start, and transmits a resonance energy generated during reversal on the secondary side of the inductance element L _1, through the rectifier circuit DB, the power supply side (for example, drive power of the switching element Q ₁₎
Return to. Thus, the voltage Vc of the capacitor C _1
1 can be suppressed, and the overall efficiency of the circuit can be improved. Furthermore, the structure of the pulse transformer can be simplified as compared with other embodiments in which a tertiary winding is provided in the pulse transformer.

FIG. 17 is a circuit diagram of a tenth embodiment of the present invention. The difference from the other embodiments is that the inductances L ₁ and L ₂ are inserted in series with the secondary winding of the pulse transformer PT,
And from immediately before the inversion of the output polarity of the inverter circuit 2 the switch SW ₁ over a period of time on state at the start, to consume the resonance energy resistance R ₁ in the loop. Also,
Since overall inductance is decreased, resonance energy generated during inversion decreases, the increase of the voltage Vc ₁ of the capacitor C ₁ can be kept low. Switch S
The control of W _1, may be applied method as described in the third embodiment. Capacitor C ₃ is a capacitor for low-pass filtering of the lamp current. In this embodiment, the switching element Q ₁ of the converter circuit unit 1 is used.
Performs power control by PWM control.

In each of the above embodiments, the input power supply may be a DC power supply or a rectified AC power supply, and the DC / DC converter circuit 1 may be any of a step-up, step-down and step-up / step-down chopper. Also flyback,
A forward, push-pull, half-bridge converter or the like may be used. The transformer of the converter circuit unit 1 may be an insulating system or a non-insulating system. The inverter circuit unit 2 may be any system such as a full-bridge or half-bridge inverter. Not limited. As switching elements, bipolar transistors, FETs,
There is no particular limitation such as a thyristor. Switching element Q ₂
As to Q _5, instead of the bipolar transistor, when utilizing such power field effect transistor, the diode D ₂ to D ₅ is not required.

[0027]

According to the present invention, a smoothing capacitor is connected to the output of a DC / DC converter circuit section connected to a DC power supply, and the voltage is converted into a rectangular wave voltage by a bridge type inverter circuit section. In a power supply device that supplies a series circuit of an element and a load, the inductance value of the inductance element is reduced for a certain period from at least immediately before the polarity of the current flowing through the load is inverted, or
The energy generated in the inductance element is
Since a means for feeding back to the source side is added, there is an effect that the resonance voltage by the inductance element and the smoothing capacitor can be suppressed, and the voltage rise of the capacitor can be suppressed.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing a basic configuration of the present invention.

FIG. 2 is an operation waveform diagram of the present invention.

FIG. 3 is an enlarged view of a main part of an operation waveform according to the present invention.

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

FIG. 5 is an operation waveform diagram of the first embodiment of the present invention.

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

FIG. 7 is an operation waveform diagram of the second embodiment of the present invention.

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

FIG. 9 is an operation waveform diagram of the third embodiment of the present invention.

FIG. 10 is an operation waveform diagram of the inverter circuit unit according to the third embodiment of the present invention.

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

FIG. 12 is a circuit diagram of a fifth embodiment of the present invention.

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

FIG. 14 is a circuit diagram of a seventh embodiment of the present invention.

FIG. 15 is a circuit diagram of an eighth embodiment of the present invention.

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 DC / DC converter circuit part 2 Inverter circuit part 3 Load circuit E DC power supply C Capacitor L Inductance element Z Load

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02M 7/48 H02M 7/5387 H05B 41/282

Claims (4)

(57) [Claims] 1. A DC power supply and a DC power supply connected to the DC power supply.
A C / DC converter circuit, a first smoothing capacitor connected to an output of the DC / DC converter circuit,
A bridge-type inverter circuit for converting the voltage of the first capacitor into a rectangular wave voltage ;
In a power supply device including a low-frequency oscillator for determining a polarity inversion cycle and a series circuit of a load and an inductance element connected to an output of an inverter circuit unit, the load is a discharge lamp.
And when a current of a predetermined value or more is flowing through the load.
The inductance element is magnetically saturated for a certain period from at least immediately before the polarity of the current flowing through the load is inverted, so that the inductance value is reduced .
A power supply device comprising: a saturable inductance ; 2. A secondary winding of a saturable pulse transformer of an igniter section for applying a starting voltage to a discharge lamp is used as the inductance element, and a pulse current is supplied in parallel with a series circuit of the inductance element and a load. power supply according to claim 1, wherein the connecting the second capacitor to bypass. 3. A DC power supply and a DC power supply connected to the DC power supply.
C / DC converter circuit and DC / DC converter circuit
A first smoothing capacitor connected to the output of the road;
For converting the voltage of the first capacitor into a rectangular wave voltage;
Bridge type inverter circuit section and inverter circuit section
A low-frequency oscillator that determines the polarity inversion cycle and an inverter circuit
Of the inductance element and the load connected to the output of the road
In a power supply device comprising a column circuit, the load is a discharge lamp, and when a current of a predetermined value or more is flowing through the load, the inductance element is provided for a certain period at least immediately before the polarity of the current flowing through the load is reversed. power supply you wherein a circuit having a switch, that detects the state of the polarity reversal of the current flowing to the load is provided a circuit for driving the switch for reducing the inductance value of. 4. A DC power supply and a DC power supply connected to the DC power supply.
C / DC converter circuit and DC / DC converter circuit
A first smoothing capacitor connected to the output of the road;
For converting the voltage of the first capacitor into a rectangular wave voltage;
Bridge type inverter circuit section and inverter circuit section
A low-frequency oscillator that determines the polarity inversion cycle and an inverter circuit
Of the inductance element and the load connected to the output of the road
In a power supply device including a column circuit, the load is a discharge lamp, and a winding magnetically coupled to the inductance element, a switch connected to the winding, and a state of polarity inversion of a current flowing through the load. A circuit for detecting and driving the switch, wherein when a current of a predetermined value or more is flowing through the load, energy generated in the inductance element is consumed for a certain period at least immediately before the polarity of the current flowing through the load is inverted. or power supply you characterized by being configured to be fed back to the power supply side.