JP2002184591A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent self-oscillation frequency drop caused by load change without adding special element. SOLUTION: A control circuit is provided as against a self-excited half bridge circuit consisting of a rectifier DB, a filter capacitor C3, switching elements Q1, Q2, a discharge lamp LAMP, a leakage transformer T1, a current transformer T2, capacitors C1, C4, C5, a diode D1 and resistors R1, R2. The control circuit is equipped with a resistor R12, a diode D12 and a transistor Q12 in addition to a series circuit of a diode D10 and a transistor Q10 and a circuit of a transistor Q11, capacitors C10, C11 and resistors R10, R11, whereby the on-state time of the switching element Q2 can be stably controlled even when an integrating circuit of the capacitor C10 is reset in a state that positive voltage is generated in a secondary winding N22 of the current transformer T2, to cause low-frequency resonance due to the change of the loaded condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting apparatus for converting a DC voltage into an AC voltage by an inverter circuit having a series circuit of a pair of switching elements and applying the AC voltage to a discharge lamp.

[0002]

2. Description of the Related Art Heretofore, various types of discharge lamp lighting devices of this type have been marketed and proposed.

[0003]

FIG. 15 shows a configuration diagram of a power supply device proposed in a separate application (Japanese Patent Application No. 2000-155567) filed by the present applicant.

A power supply device shown in FIG. 15 is a discharge lamp LAMP.
This is a so-called discharge lamp lighting device having a load as a load, and is roughly composed of a self-excited half-bridge circuit and another control circuit.

[0005] The self-excited half-bridge circuit uses an AC power supply V
s and a capacitor C4 and a diode D connected between the output terminals of the rectifier DB.
1, a series circuit of a parallel circuit and a switching element (FET having a regenerative diode in the figure) Q1 and Q2; a smoothing capacitor C3 connected in parallel to the switching elements Q1 and Q2 in the series circuit;
The primary winding N21 of the current transformer T2, the primary winding N11 of the leakage transformer T1, and the capacitor C5 connected between the connection point of Q2 and the negative output of the rectifier DB.
And the secondary winding N1 of the leakage transformer T1
Discharge lamp LAMP and capacitor C connected between the two
1, a series circuit of a secondary winding N23 and a resistor R1 of a current transformer connected between the gate and source of the switching element Q1, and a current transformer connected between the gate of the switching element Q2 and the ground. Of the secondary winding N22 and a series circuit of the resistor R2.

The other control circuit includes a series circuit of a diode D10 and a transistor Q10 connected between the gate and the source of the switching element Q2, and a transistor Q11 having a base and an emitter connected to the base and the emitter of the transistor Q10, respectively. A capacitor C10 connected between the base and the emitter of the transistor Q10, a capacitor C11 connected between the base and the emitter of the transistor Q11, and a connection between the drain of the switching element Q2 and the base of the transistor Q11. Resistance R1
1 and a resistor R10 connected between the drain of the switching element Q1 and the base of the transistor Q10.

FIG. 16 is an operation waveform diagram of FIG. 15. The operation of the above circuit will be described with reference to FIG. When the half-bridge circuit performs a self-excited operation, a positive / negative ON / OFF signal such as “Vgs” shown in FIG. 16 appears at the gate terminal of the switching element Q2.

When the switching element Q2 is turned on, the voltage at the connection point between the switching elements Q1 and Q2 becomes zero, so that the base potential of the transistor Q11 discharging the capacitor C10 (the voltage VC11 across the capacitor C11) eventually becomes zero. As a result, the transistor Q11 turns off.
Thereby, charging of the capacitor C10 starts. After a lapse of a certain time, the potential of the capacitor C10 (voltage VC10) becomes a voltage at which the transistor Q10 can be turned on, and the transistor Q10 is turned on. As a result, the gate and source of the switching element Q2 are short-circuited, and the switching element Q2 is turned off.

Thereafter, the regenerative diode of the switching element Q1 is turned on by the commutation of the resonance circuit. When the switching element Q1 is turned on, the switching element Q1 is turned on.
Since the voltage at the connection point between 1 and Q2 becomes equal to the voltage charged in the capacitor C3, the base voltage of the transistor Q11 eventually rises to a voltage at which the transistor Q11 is turned on, and the transistor Q11 is turned on. When the transistor Q11 turns on, the capacitor C10 discharges,
The transistor Q10 turns off.

[0010] By repeating such an operation, the on time of the switching element Q2 is particularly controlled by the above-mentioned control circuit.

However, in the above-described circuit configuration, the resonance frequency changes due to a load change, and the self-excited oscillation frequency often drops extremely. When the oscillation frequency is extremely lowered, an abnormal operation as shown in FIG. 17 occurs.
This is because the regenerative diode of the switching element Q1 is turned on by the commutation of the resonance circuit from the on state of the switching element Q2, but the switching element Q2 is turned off after a certain time from the timing when the regenerative diode of the switching element Q1 is turned on. This is because if the regeneration continues for a certain period of time to turn off the transistor Q10 that has been turned off, the transistor Q10 is turned on even though a voltage for turning on the switching element Q2 is generated in the current transformer T2.

As a result, the resonance current is
The switching element Q2 is turned on while flowing through the one regenerative diode, a through current is generated in the switching elements Q1 and Q2, and the switching element causes di / dt stress destruction.

As a preventive measure, an integrating capacitor C10
A method of increasing the delay of a predetermined time until resetting of the switching element Q1 to prevent the switching element Q2 from turning on when a regenerative current is flowing through the switching element Q1 is employed. However, if the delay of the integration reset circuit is increased, on the contrary, when the resonance frequency becomes higher due to the state of the discharge lamp, the timing at which the ON signal of the switching element Q2 is generated before the integration capacitor C10 is reset is performed. The element Q2 cannot be turned on, and eventually the oscillation stops.

The present invention has been made in view of the above circumstances, and provides a discharge lamp lighting device capable of reliably preventing a decrease in a self-excited oscillation frequency due to a load change without adding a special element. The purpose is to:

[0015]

According to a first aspect of the present invention, there is provided a discharge lamp lighting apparatus comprising: an AC power supply; a rectifier for rectifying the AC power; and a rectifier output of the rectifier. A smoothing capacitor, an inverter circuit having a series circuit of a pair of switching elements and converting the DC voltage of the smoothing capacitor into an AC voltage by switching the switching elements with these switching elements, and at least a discharge lamp and an LC resonance circuit; A load circuit connected between both ends of one of the switching elements, a self-excited drive circuit including a drive transformer for alternately turning on and off the pair of switching elements, a timer circuit including a resistor and a capacitor, and the switching circuit. A separate control circuit for controlling the ON time of the element according to the time determined by the timer circuit. For example, by detecting the self-excited width signal, characterized in that resetting the timer circuit.

According to a second aspect of the present invention, in the discharge lamp lighting device of the first aspect, a power supply of the timer circuit is a connection point of a series circuit of a pair of switching elements, and a drive transformer resets a capacitor of the timer circuit. And detecting the voltage.

According to a third aspect of the present invention, in the discharge lamp lighting device according to the first aspect, a power supply of the timer circuit is a connection point of a series circuit of a pair of switching elements, and a reset of a capacitor of the timer circuit is performed by a driving transformer. Is performed when the voltage is positive.

According to a fourth aspect of the present invention, in the discharge lamp lighting device according to the first aspect, a power supply of the timer circuit is used as a power supply of an inverter, and a capacitor of the timer circuit is reset using a negative voltage of a driving transformer. It is characterized by performing.

According to a fifth aspect of the present invention, in the discharge lamp lighting device according to the first aspect, a power supply of the timer circuit is a connection point of a series circuit of a pair of switching elements, and a drive transformer resets a capacitor of the timer circuit. And detecting the negative voltage.

According to a sixth aspect of the present invention, in the discharge lamp lighting device of the first aspect, a power supply of the timer circuit is used as a drive transformer, and a capacitor of the timer circuit is reset using a negative voltage of the drive transformer. It is characterized by the following.

According to a seventh aspect of the present invention, in the discharge lamp lighting device of the first aspect, a power supply of the timer circuit is a transformer connected to a load, and a capacitor of the timer circuit is reset by a negative voltage of a driving transformer. It is characterized by performing detection.

[0022]

FIG. 1 is a block diagram of a discharge lamp lighting device according to a first embodiment of the present invention, and FIG. 2 is an operation waveform diagram of FIG. Hereinafter, the first embodiment will be described with reference to these drawings.

The discharge lamp lighting device shown in FIG. 1 is provided with a self-excited half-bridge circuit in the same manner as the power supply device shown in FIG. 15, and is different from the power supply device in that a self-excited amplitude signal is detected and maintained. A control circuit having means for performing the control.

The control circuit of FIG. 1 has the same structure as that of the control circuit of FIG. 15 except that a resistor connected in series between the connection point of the secondary winding N22 and the resistor R2 and the source of the switching element Q2. R12 and a diode D12, and a transistor Q12 having a base and an emitter connected to both ends of the diode D12 and a collector connected to the base of the transistor Q11.

Next, the operation of the first embodiment will be described. When the half-bridge circuit operates by itself, the switching element Q
A positive / negative ON / OFF signal such as “Vgs” shown in FIG. 2 appears at the gate terminal 2.

When the gate voltage of the switching element Q2 is positive, the transistor Q12 is turned on by the current flowing from the resistor R12, and discharges the capacitor C11. Therefore, the transistor Q11 cannot be turned on.

Eventually, the resistor R10 and the capacitor C10
, The transistor Q10 is turned on. When the transistor Q10 turns on, the gate terminal of the switching element Q2 is connected to the diode D10 and the transistor Q1
The short circuit occurs due to 0, the switching element Q2 is turned off, and the transistor Q10 continues to be turned on by the current flowing from the resistor R10. Even when the transistor Q10 is turned on, a positive voltage is generated in the secondary winding N22 of the current transformer T2, so that the transistor Q12 continues to be turned on via the resistor R12.

When the current flowing through the primary winding N21 of the current transformer T2 is inverted by the resonance circuit in the self-excited half-bridge circuit, the voltage appearing on the secondary winding N22 is also inverted, and there is no current for turning on the transistor Q12. , The transistor Q12 turns off. As a result, the resistance R
Since the transistor Q11 is turned on by the power supply from the power supply 11, the integrating circuit including the resistor R10 and the capacitor C10 that turned on the transistor Q10 is discharged, and the transistor Q10 is turned off. While a negative voltage appears on the secondary winding N22 of the current transformer T2, the transistor Q12 does not turn on, and thus the transistor Q11 maintains the capacitor C10 at 0V.

Then, the secondary winding N22 of the current transformer T2 is formed by the resonance circuit in the self-excited half bridge circuit.
, A transistor Q12 turns on again, the transistor Q11 turns off, and the integrating circuit including the resistor R10 and the capacitor C10 starts an integrating operation.

By the above operation, switching element Q2
Can be turned on by the self-excited signal, that is, while the positive voltage is generated in the secondary winding N22 of the current transformer T2, the integration circuit of the capacitor C10 is reset and the switching element Q2 is prevented from turning on again. Can come off. Therefore, even if low-frequency resonance occurs due to a change in the load state, it is possible to stably control the ON time of the switching element Q2.

In the first embodiment, the diode D1
And a circuit configuration including the capacitor C4. However, as shown in FIG. 3, the circuit configuration may not include the diode D1 and the capacitor C4. In this case, the same effect can be obtained.

Further, the power supply of the integrating circuit is used as a separately provided control power supply, the capacitor of the integrating circuit is reset by detecting the negative voltage of the current transformer, and a photocoupler is used for resetting the capacitor of the integrating circuit. Configuration, a configuration for detecting the current of the current transformer for resetting the capacitor of the integration circuit, a configuration for using the voltage of the tertiary winding of the current transformer for resetting the capacitor of the integration circuit, or a load for resetting the capacitor of the integration circuit A configuration using the voltage of the tertiary winding of the connected leakage transformer may be used, and a specific configuration thereof will be described later.

FIG. 4 is a configuration diagram of a discharge lamp lighting device according to a second embodiment of the present invention. Hereinafter, the second embodiment will be described with reference to FIG.

The discharge lamp lighting device shown in FIG. 4 has a self-excited half-bridge circuit as in the first embodiment, and differs from the first embodiment in that a smoothing capacitor C
3 and a resistor R10 and a capacitor C connected between terminals
10, a connection point between the resistor R10 and the capacitor C10 and the secondary winding N2 of the current transformer T2.
And an integrating reset circuit composed of a diode D100 and a resistor R12 connected between the node of the switching element Q2 and the resistor R2, and a Q composed of a diode D10 and a transistor Q10 connected between the gate and source of the switching element Q2.
(2) A separate control circuit including a forced off circuit and a diode D101 connected in parallel with the capacitor C10. However, the collector and the emitter of the transistor Q10 are connected between the diode D10 and the source of the switching element Q2, respectively.
The base of 10 is connected to the connection point of the resistor R10 and the capacitor C10.

Next, the operation of the second embodiment will be described. When the half-bridge circuit performs a self-excited operation, as described above, the positive / negative ON / OFF state is applied to the gate terminal of the switching element Q2.
An off signal appears.

When the gate voltage of the switching element Q2 is positive, voltage integration is performed by the capacitor C10 in the resistor R10 and the capacitor C10 of the integrating circuit, and eventually exceeds the threshold value of the transistor Q10 and the transistor Q1
0 turns on and the switching element Q2 turns off. When the switching element Q2 is turned off, the transistor Q10 continues to be turned on unless the capacitor C10 is reset, so that the switching element Q2 is not turned on again.

When the current flowing through the primary winding N21 of the current transformer T2 is inverted by the resonance circuit in the self-excited half-bridge circuit, the voltage appearing on the secondary winding N22 is also inverted to a negative potential. Then, the capacitor C10, the diode D100, the resistor R12, the current transformer T2
, The capacitor C10 is reset in the path of the secondary winding N22, and the base bias of the transistor Q10 is released. The discharging of the capacitor C10 is performed during a period when the gate voltage of the switching element Q2 is negative.

When the gate potential of the switching element Q2 becomes positive, the discharging of the capacitor C10 is stopped by the diode D100, and the integration of the capacitor C10 is restarted by the resistor R10.

This embodiment is an example in which a negative voltage of the gate voltage is detected and the integration circuit is reset as a period during which the controlling switching element is always turned off.
Even if low-frequency resonance occurs due to a change in the load state, it is possible to stably control the ON time of the switching element.

FIG. 5 is a configuration diagram of a discharge lamp lighting device according to a third embodiment of the present invention. Hereinafter, the third embodiment will be described with reference to FIG.

The discharge lamp lighting device shown in FIG. 5 includes a self-excited half-bridge circuit as in the second embodiment, and further includes a different control circuit different from the second embodiment.
The control circuit includes an integrating circuit including a resistor R10 and a capacitor C10, a Q2 forced off circuit including a diode D10 and a transistor Q10, as in the control circuit according to the second embodiment.
The transistor Q13 has an emitter and a collector connected to both ends of the transistor Q0, respectively, and diodes D100, D102 and a resistor R12 connected between the base of the transistor Q13 and a connection point of the secondary winding N22 and the resistor R2. And an integration reset circuit comprising:

As in the second embodiment, this discharge lamp lighting device is a circuit for discharging and resetting the capacitor C10 of the integrating circuit when the gate voltage of the switching element Q2 becomes negative. The operation waveform diagram of this configuration is the same as in the first and second embodiments, as shown in FIG.

The difference from the second embodiment is that a PNP transistor Q13 is used for discharging the capacitor C10. In the second embodiment, the discharge speed of the capacitor C10 is delayed by the resistor R12, which may make the control circuit design difficult. In the third embodiment, the discharge timing of the integration capacitor C10 is determined by the resistor R1.
2 and the diodes D100 and D102, and discharging is performed by the transistor Q13, so that the control circuit can be easily designed.

The diodes D100 and D102 are elements for determining a negative voltage for the reset operation, and the number of series diodes can be arbitrarily set.

FIG. 7 is a configuration diagram of a discharge lamp lighting device according to a fourth embodiment of the present invention. Hereinafter, the fourth embodiment will be described with reference to FIG.

The discharge lamp lighting device shown in FIG. 7 has a self-excited half-bridge circuit as in the first embodiment, and also has a different control circuit different from the first embodiment.
The other control circuit includes a series circuit of zener diodes ZD1 and ZD2 connected between the gate and source of the switching element Q2, a diode D10 and a transistor Q1 connected between the gate and source of the switching element Q2.
0 series circuit and the secondary winding N2 of the current transformer T2.
It comprises a resistor R10 and a capacitor C10 connected between a connection point of the switching element Q2 and the resistor R2 and the source terminal of the switching element Q2, and a diode D103 connected in parallel with the capacitor C10.

This discharge lamp lighting device is characterized in that, unlike the first to third embodiments, the integral power supply of the other control circuit is obtained from the current transformer T2.

In this discharge lamp lighting device, when the half-bridge circuit operates by itself, positive and negative ON / OFF signals appear at the gate terminal of the switching element Q2.

When the gate voltage of the switching element Q2 is positive, the voltage of the capacitor C10 is integrated by the resistor R10 of the integrating circuit and the capacitor C10, and eventually exceeds the threshold value of the transistor Q10.
0 turns on and the switching element Q2 turns off. Also,
Even if the transistor Q10 is turned on and the gate and source of the switching element Q2 are short-circuited, a positive voltage is generated in the secondary winding N22 of the current transformer T2, so that the transistor Q10 is turned on via the resistor R10. to continue.

When the current flowing through the primary winding N21 of the current transformer T2 is inverted by the resonance circuit in the self-excited half-bridge circuit, the voltage appearing on the secondary winding N22 is also inverted, and there is no current for turning on the transistor Q10. , The transistor Q10 turns off. While a negative voltage appears in the secondary winding N22 of the current transformer T2, the diode D103, the resistor R10, the current transformer T2
Current continues to flow through the path of the secondary winding N22, and the capacitor C10 is reset with a negative potential corresponding to the forward voltage of the diode D103.

The secondary winding N22 of the current transformer T2 is provided by the resonance circuit in the self-excited half bridge circuit.
When a positive voltage appears on the resistor R10 and the capacitor C
The integration circuit by 10 starts operating.

As described above, in the fourth embodiment, the on-time of the switch can be stably controlled with a small number of components even if low-frequency resonance occurs due to a change in the load state.

FIG. 8 is a configuration diagram of a discharge lamp lighting device according to a fifth embodiment of the present invention. Hereinafter, the fifth embodiment will be described with reference to FIG.

The discharge lamp lighting device shown in FIG. 8 has a self-excited half-bridge circuit as in the third embodiment, and also has a different control circuit different from the third embodiment.
The other control circuit uses the smoothing capacitor C3
The third embodiment differs from the control circuit of the third embodiment in that the current is not taken from the leakage transformer T1 but from the leakage transformer T1. That is,
A secondary winding N13 having one end connected to the anode of the diode D1 with respect to the leakage transformer T1;
A diode D50 is connected in series with the other end of the secondary winding N13, and a capacitor C50 is connected in parallel with the series diode D50 and the secondary winding N13. The power supply is configured to take power.

As described above, the same effect as in the third embodiment can be obtained even in the configuration in which the power supply of the integration circuit is obtained from the auxiliary winding of the leakage transformer T1.

FIG. 9 is a configuration diagram of a discharge lamp lighting device according to a sixth embodiment of the present invention. Hereinafter, the sixth embodiment will be described with reference to FIG.

The discharge lamp lighting device shown in FIG. 9 includes a self-excited half-bridge circuit as in the third embodiment, and further includes a different control circuit different from the third embodiment.
The other control circuit uses the smoothing capacitor C3
As shown in FIG. 9, the present embodiment differs from the control circuit of the third embodiment in that it is obtained from a DC power supply E, as shown in FIG.

As described above, even in the configuration in which the power supply of the integration circuit is obtained from the DC power supply, the same effect as that of the third embodiment can be obtained, and accurate on-time control can be performed by setting the voltage source of the integration circuit to a constant voltage. It can be carried out.

FIG. 10 is a configuration diagram of a discharge lamp lighting device according to a seventh embodiment of the present invention. In the following, the seventh
An embodiment will be described.

The discharge lamp lighting device shown in FIG. 10 includes a self-excited half-bridge circuit as in the first embodiment, and further includes a different control circuit different from the first embodiment.
This alternative circuit comprises a diode D10 and a transistor Q10 connected between the gate and source of the switching element Q2, and a resistor R12 and a capacitor C12 connected between the DC power supply Vcc and the source of the switching element Q2.
10, an integrating circuit, a light receiving element (phototransistor in the figure) of the photocoupler PC connected in parallel with the capacitor C10, and a light emitting element (light emitting in the figure) of the photocoupler PC connected between the gate and source of the switching element Q1. (A diode) and a series circuit of a resistor R201.

This discharge lamp lighting device is characterized in that the gate voltage of the switching element Q1 is used as detecting means for resetting the integrating circuit consisting of the resistor R12 and the capacitor C10. That is, the switching element Q1
With the light on, the light receiving element of the photocoupler PC emits light,
The light emitting element turns on and discharges the capacitor C10.

In the seventh embodiment, the switching element Q1
By resetting the integration circuit only when is turned on, it is possible to eliminate integration reset during a period in which the switching element Q2 can be turned on.

FIG. 11 is a configuration diagram of a discharge lamp lighting device according to an eighth embodiment of the present invention. Hereinafter, the eighth diagram will be described with reference to FIG.
An embodiment will be described.

The discharge lamp lighting device shown in FIG. 11 has a self-excited half-bridge circuit as in the seventh embodiment, and further has a different control circuit different from the seventh embodiment.
The other control circuit includes a Q2 forced off circuit including a diode D10 and a transistor Q10, an integrating circuit including a resistor R12 and a capacitor C10, and a capacitor C1.
A light-receiving element of a photocoupler PC connected in parallel with 0;
A photocoupler P connected between the secondary winding N22 of the current transformer T2 and the source of the switching element Q2
A light emitting element of C and a parallel circuit of a diode D201.

As described above, the same effect as that of the seventh embodiment can be obtained by the configuration in which the negative current of the secondary winding N22 of the current transformer T2 is detected and the capacitor C10 of the integration circuit is discharged and reset.

FIG. 12 is a configuration diagram of a discharge lamp lighting device according to a ninth embodiment of the present invention. Hereinafter, the ninth will be described with reference to FIG.
An embodiment will be described.

The discharge lamp lighting device shown in FIG. 12 has a self-excited half-bridge circuit as in the eighth embodiment, and also has a different control circuit different from that of the eighth embodiment.
The other control circuit includes a Q2 forced off circuit and an integration circuit similar to those in the eighth embodiment, and a winding N2 of a current transformer T2.
4 and a voltage dividing circuit of resistors R301 and R302, and a diode D1 connected in parallel with the resistor R302.
1 and a transistor Q11 connected in parallel with the capacitor C10. However, the collector and the emitter of the transistor Q11 are connected to the capacitor C10.
And the base of the transistor Q11 is connected to the connection point of the diode D11 and the resistor R302.

As described above, the winding N which generates a voltage having a polarity opposite to that of the secondary winding N22 of the current transformer T2 which is the winding of the drive signal of the switching element Q2 to be controlled.
Even with the configuration using the reset signal 24, it is possible to reliably prevent the self-excited oscillation frequency from being lowered due to a load change.

FIG. 13 is a configuration diagram of a discharge lamp lighting device according to a tenth embodiment of the present invention. Hereinafter, the tenth embodiment will be described with reference to FIG.

The discharge lamp lighting device shown in FIG. 13 includes a self-excited half bridge circuit as in the first embodiment, and further includes a different control circuit different from the first embodiment.
The other control circuit includes a tertiary winding N13 provided in the leakage transformer T1 and having one end connected to GND, and a capacitor C501 connected in series between the other end of the tertiary winding N13 and the source of the switching element Q2. And the resistor R5
01, a series circuit of a diode D10 and a transistor Q10 connected in parallel between the gate and source terminals of the switching element Q2, and a resistor connected in series between the DC voltage source Vcc and the source of the switching element Q2. R
12 and an integrating circuit of the capacitor C10, a transistor Q11 connected in parallel with the capacitor C10, and a resistor R502 connected between a connection point of the capacitor C501 and the resistor R501 and the base of the transistor Q11. However, the collector and the emitter of the transistor Q10 are connected between the diode D10 and the source of the switching element Q2, respectively, and the base of the transistor Q10 is connected to the connection point of the resistor R12 and the capacitor C10. The collector and the emitter of the transistor Q11 are connected to both ends of the capacitor C10.

This discharge lamp lighting device includes a switching element Q2 composed of a DC power supply Vcc, a resistor R12, a capacitor C10, a diode D10, and a transistor Q10.
A voltage signal (VN1 in FIG. 14) of the tertiary winding N13 of the leakage transformer T1 is used as a timing for discharging and resetting the integration capacitor C10 of the circuit for limiting the ON time of the circuit.
3) is obtained by differentiating a differential circuit (VR501 in FIG. 14) using a differentiating circuit composed of a capacitor C501 and a resistor R501.

As described above, the integration capacitor C1 is synchronized with the tertiary winding N13 of the leakage transformer T1.
By resetting 0, the switching element Q2 can be stably controlled even if a resonance frequency change due to a load change occurs.

[0073]

According to a first aspect of the present invention, there is provided a discharge lamp lighting device comprising: a series circuit of an AC power supply, a rectifier for rectifying the AC power, a smoothing capacitor for smoothing a rectified output of the rectifier, and a pair of switching elements. An inverter circuit that has a switching element to convert the DC voltage of the smoothing capacitor into an AC voltage by switching the DC voltage,
A load circuit including at least a discharge lamp and an LC resonance circuit, connected between one ends of the pair of switching elements; a self-excited drive circuit including a drive transformer for alternately turning on and off the pair of switching elements; And a timer circuit configured by a capacitor, and a control circuit for controlling the ON time of the switching element according to the time determined by the timer circuit, and detecting the self-excited amplitude signal to reset the timer circuit. Therefore, it is possible to reliably prevent the self-excited oscillation frequency from being lowered due to a load change without adding a special element.

According to a second aspect of the present invention, in the discharge lamp lighting device according to the first aspect, a power supply of the timer circuit is a connection point of a series circuit of a pair of switching elements, and a drive transformer resets a capacitor of the timer circuit. The timer circuit is reset during the period when the switching element can be turned on by the self-excited signal, and even if low-frequency resonance occurs due to a change in the load state, the on-time of the switching element is controlled stably. It can be carried out.

According to a third aspect of the present invention, in the discharge lamp lighting device according to the first aspect, a power supply of the timer circuit is a connection point of a series circuit of a pair of switching elements, and a reset of a capacitor of the timer circuit is performed by a driving transformer. When the voltage of the switching element is positive, the timer circuit is reset while the switching element can be turned on by the self-excited signal. It can be performed.

According to a fourth aspect of the present invention, in the discharge lamp lighting device according to the first aspect, a power supply of the timer circuit is used as a power supply of an inverter, and a capacitor of the timer circuit is reset using a negative voltage of a driving transformer. Do it,
Even with this configuration, even if low-frequency resonance occurs
It is possible to stably control the ON time of the switching element.

According to a fifth aspect of the present invention, in the discharge lamp lighting device of the first aspect, a power supply of the timer circuit is a connection point of a series circuit of a pair of switching elements, and a reset of a capacitor of the timer circuit is performed by a driving transformer. In this configuration, the on-time of the switching element can be stably controlled even if low-frequency resonance occurs due to a change in the load state.

According to a sixth aspect of the present invention, in the discharge lamp lighting device of the first aspect, a power supply of the timer circuit is used as a drive transformer, and a capacitor of the timer circuit is reset using a negative voltage of the drive transformer. Therefore, even with this configuration, the on-time of the switching element can be stably controlled even if low-frequency resonance occurs due to a change in the load state.

According to a seventh aspect of the present invention, in the discharge lamp lighting device according to the first aspect, the power supply of the timer circuit is a transformer connected to a load, and the capacitor of the timer circuit is reset by a negative voltage of the driving transformer. In this configuration, the on-time of the switching element can be stably controlled even if low-frequency resonance occurs due to a change in the load state.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a discharge lamp lighting device according to a first embodiment of the present invention.

FIG. 2 is an operation waveform diagram of the discharge lamp lighting device of FIG.

FIG. 3 is a diagram showing another configuration example similar to the discharge lamp lighting device of FIG. 1;

FIG. 4 is a configuration diagram of a discharge lamp lighting device according to a second embodiment of the present invention.

FIG. 5 is a configuration diagram of a discharge lamp lighting device according to a third embodiment of the present invention.

6 is an operation waveform diagram of the discharge lamp lighting device of FIG.

FIG. 7 is a configuration diagram of a discharge lamp lighting device according to a fourth embodiment of the present invention.

FIG. 8 is a configuration diagram of a discharge lamp lighting device according to a fifth embodiment of the present invention.

FIG. 9 is a configuration diagram of a discharge lamp lighting device according to a sixth embodiment of the present invention.

FIG. 10 is a configuration diagram of a discharge lamp lighting device according to a seventh embodiment of the present invention.

FIG. 11 is a configuration diagram of a discharge lamp lighting device according to an eighth embodiment of the present invention.

FIG. 12 is a configuration diagram of a discharge lamp lighting device according to a ninth embodiment of the present invention.

FIG. 13 is a configuration diagram of a discharge lamp lighting device according to a tenth embodiment of the present invention.

14 is an operation waveform diagram of the discharge lamp lighting device of FIG.

FIG. 15 is a configuration diagram of a power supply device proposed in a separate application filed by the present applicant.

16 is an operation waveform diagram of the power supply device of FIG.

17 is an explanatory diagram of a problem of the power supply device of FIG.

[Explanation of symbols]

 LAMP Discharge lamp DB Rectifier Q1, Q2 Switching element Q10, Q11, Q12 Transistor T1 Leakage transformer T2 Current transformer C1, C4, C5, C10, C11 Capacitor C3 Smoothing capacitor D1, D10, D12 Diode R1, R2, R10, R11, R12 resistance

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshiya Kamsha 1048, Kazumasa Kadoma, Osaka Prefecture Matsushita Electric Works, Ltd. (72) Inventor Joji Oyama 1048, Kazuma Kazuma, Kadoma, Osaka Prefecture Matsushita Electric Works, Ltd. F term (reference) 3K072 AA02 BA03 BB01 BC03 CA16 CB07 DB03 DD04 DE06 EB01 GA01 GB12 GC02 GC04 GC09 HA09 HB03

Claims (7)

[Claims] An AC power supply; a rectifier for rectifying the AC power; a smoothing capacitor for smoothing a rectified output of the rectifier; and a series circuit of a pair of switching elements. An inverter circuit that converts the pair of switching elements into an AC voltage, a load circuit that includes at least a discharge lamp and an LC resonance circuit, is connected between one ends of the pair of switching elements, and a drive transformer that includes a drive transformer. A self-excited drive circuit that turns on and off the elements alternately, a timer circuit configured by a resistor and a capacitor, and a control circuit that controls the on time of the switching element according to a time determined by the timer circuit; Detecting the self-excited amplitude signal and resetting the timer circuit. Lamp lighting device. 2. The method according to claim 1, wherein a power supply of said timer circuit is a connection point of a series circuit of a pair of switching elements, and resetting of a capacitor of said timer circuit is performed by detecting a voltage of a driving transformer. Discharge lamp lighting device. 3. The timer circuit according to claim 1, wherein a power supply of said timer circuit is a connection point of a series circuit of a pair of switching elements, and resetting of a capacitor of said timer circuit is performed when a voltage of a driving transformer is positive. Discharge lamp lighting device. 4. The discharge lamp lighting device according to claim 1, wherein a power supply of said timer circuit is used as a power supply of an inverter, and a capacitor of said timer circuit is reset using a negative voltage of a driving transformer. 5. The timer circuit according to claim 1, wherein a power source of said timer circuit is a connection point of a series circuit of a pair of switching elements, and resetting of a capacitor of said timer circuit is performed by detecting a negative voltage of a driving transformer. Discharge lamp lighting device. 6. The discharge lamp lighting device according to claim 1, wherein a power supply of the timer circuit is used as a drive transformer, and the capacitor of the timer circuit is reset using a negative voltage of the drive transformer. 7. The discharge lamp according to claim 1, wherein a power supply of the timer circuit is a transformer connected to a load, and resetting of a capacitor of the timer circuit is performed by detecting a negative voltage of a driving transformer. apparatus.