JP3687177B2 - Discharge lamp lighting device and lighting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a discharge lamp lighting device and a lighting device for lighting a discharge lamp.
[0002]
[Prior art]
Conventionally, in a self-excited clean bridge discharge lamp lighting device using a saturable current transformer, the first and second switching on the high (H) side and the low (L) side connected between the output terminals of the rectifier circuit By alternately turning the means on and off using a saturable current transformer connected in series to the inductor, a high-frequency current is passed through the inductor, and a high-frequency output from the inductor is supplied to the discharge lamp. Here, when the starting voltage of the discharge lamp is generated and when it is lit, the on / off cycle of the first and second switching means is changed to obtain the necessary lamp power and lamp voltage when the starting voltage is generated. However, since the control in this case is performed only by the circuit that controls the switching means on the L side, the response (gain) of such a control circuit must be set in a wide range, and the starting voltage value and the power supply of the rectifier circuit It has been difficult to achieve both constant light output during lighting due to voltage fluctuation.
[0003]
[Problems to be solved by the invention]
In the conventional discharge lamp lighting device described above, the lamp power required when starting voltage is generated by changing the on / off cycle of the first and second switching means when the starting voltage is generated and when the discharge lamp is lit. In this case, since the control is performed only by the control circuit that controls the low-side switching means, it is necessary to set the response (gain) of such a control circuit over a wide range. It has been difficult to achieve both constant light output during lighting due to fluctuations in the starting voltage value and the power supply voltage of the rectifier circuit.
[0004]
Therefore, the present invention has an object to provide a discharge lamp lighting device and a lighting device that can make the control level of a control circuit that controls the low-side switching means constant when the starting voltage of the discharge lamp is generated and when it is turned on. .
[0005]
[Means for Solving the Problems]
The discharge lamp lighting device according to claim 1 rectifies the output voltage of the AC power source and outputs a DC voltage; and between the output terminals of the rectifier circuit Connected in series, High side and low side between the output terminals of the rectifier circuit, respectively To perform switching operation alternately on and off. First and second Field effect transistor When; First and second capacitors connected in series between output terminals of the rectifier circuit, the first capacitor having a relatively large capacity and provided in parallel to the first field effect transistor; The second capacitor has a smaller capacity than the first capacitor and is provided in parallel with the second field effect transistor; and the first and second field effect transistors; An inductor connected between a connection point and a connection point of the first and second capacitors, and forming a resonance circuit with the second capacitor during an ON period of the second field effect transistor; A saturable current transformer in which a primary winding is connected in series to the inductor; an output circuit that supplies a high-frequency output obtained based on resonance of the inductor and the second capacitor to a discharge lamp; Using the first and second secondary windings, respectively, the first and second Field effect transistor By alternately applying an on-voltage to the control terminals of the first and second terminals, Field effect transistor First and second drive circuits that alternately turn on and off; and first and second controlled impedance means connected in parallel to the first and second secondary windings of the saturable current transformer, respectively. Controlling the impedance of the first and second controlled impedance means by controlling the presence or absence of current flowing from the output ends of the first and second secondary windings, First and second control circuits for independently controlling the ON width by the first and second drive circuits; A feedback control circuit for supplying a control voltage to the second control circuit based on a voltage between the output terminals of the rectifier circuit, and preventing fluctuations in the output of the inductor due to fluctuations in the power supply voltage of the rectifier circuit; A Zener diode provided in parallel with the control impedance means of the first control circuit for controlling the switching frequency by changing the on width of the first and second field effect transistors, In a period, the output voltage of the first secondary winding of the saturable current transformer exceeds the Zener voltage of the Zener diode to increase the switching frequency of the first and second field effect transistors, After the preheating period, the zener diode is turned on, and the control impedance of the first control circuit is lowered. A zener diode which operates to lower the switching frequency of the first and second field effect transistors; It is characterized by comprising.
[0006]
The discharge lamp lighting device according to claim 2 rectifies the output voltage of the AC power supply and outputs a DC voltage; and between the output terminals of the rectifier circuit Connected in series, High side and low side between the output terminals of the rectifier circuit, respectively To perform switching operation alternately on and off. First and second Field effect transistor When; First and second capacitors connected in series between output terminals of the rectifier circuit, the first capacitor having a relatively large capacity and provided in parallel to the first field effect transistor; The second capacitor has a smaller capacity than the first capacitor and is provided in parallel with the second field effect transistor; and the first and second field effect transistors; An inductor connected between a connection point and a connection point of the first and second capacitors, and forming a resonance circuit with the second capacitor during an ON period of the second field effect transistor; A saturable current transformer in which a primary winding is connected in series to the inductor; an output circuit that supplies a high-frequency output obtained based on resonance of the inductor and the second capacitor to a discharge lamp; Using the first and second secondary windings, respectively, the first and second Field effect transistor By alternately applying an on-voltage to the control terminals of the first and second terminals, Field effect transistor First and second drive circuits that alternately turn on and off; and first and second controlled impedance means connected in parallel to the first and second secondary windings of the saturable current transformer, respectively. Controlling the impedance of the first and second controlled impedance means by controlling the presence or absence of current flowing from the output ends of the first and second secondary windings, First and second control circuits for independently controlling the ON width by the first and second drive circuits; A feedback control circuit for supplying a control voltage to the second control circuit based on a voltage between the output terminals of the rectifier circuit, and preventing fluctuations in the output of the inductor due to fluctuations in the power supply voltage of the rectifier circuit; A Zener diode provided in parallel with the control impedance means of the first control circuit for controlling the switching frequency by changing the on width of the first and second field effect transistors, In a period, the output voltage of the first secondary winding of the saturable current transformer exceeds the Zener voltage of the Zener diode to increase the switching frequency of the first and second field effect transistors, After the preheating period, the zener diode is turned on, and the control impedance of the first control circuit is lowered. A zener diode which operates to lower the switching frequency of the first and second field effect transistors; Comprising the above Zener diode Will not work when the discharge lamp is lit, and will work when a starting voltage is generated Zener diode Zener The voltage value is set.
[0009]
Claim 3 The discharge lamp lighting device according to claim 1 is the discharge lamp lighting device according to any one of claims 1 and 2, wherein an electrolytic capacitor is used as the first capacitor.
[0010]
Claim 4 The lighting device according to claim 1 to claim 1. 3 A discharge lamp lighting device according to any one of the above; and a lighting fixture main body that houses the discharge lamp lighting device.
[0011]
Claim 5 The lighting device according to claim 1, wherein the main body of the appliance; a discharge lamp mounted on the main body of the appliance; and lighting the discharge lamp. 3 A discharge lamp lighting device according to any one of the above.
[0012]
Claims 1 to 3 According to the configuration described, Zener diode Zener By setting the voltage value to an appropriate value, the control level of the control circuit that controls the low-side switching means can be made constant when the starting voltage of the discharge lamp is generated and when it is turned on.
[0013]
Claim 4 and 5 According to the described configuration, claims 1 to 3 The discharge lamp lighting device according to any one of the above can be applied to a discharge lamp lighting device.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
FIG. 1 is a circuit diagram showing an embodiment of a discharge lamp lighting device according to the present invention.
[0016]
In FIG. 1, an AC power supply 11 has one output terminal connected to one end of a choke coil L1 via a power switch SW1. The other end of the choke coil L1 is connected to one input terminal of the rectifier circuit 12 using a diode bridge, and the other output terminal of the AC power supply 11 is connected to one end of the choke coil L2. The other end of the choke coil L2 is connected to the other input terminal of the rectifier circuit 12. The choke coil L1 and the choke coil L2 are magnetically coupled. A capacitor C1 is connected between one ends of the choke coils L1 and L2. A capacitor C2 is connected between the other ends of the choke coils L1 and L2.
[0017]
The positive output terminal of the rectifier circuit 12 is connected to the positive input terminal of the inverter 20. An output terminal on the negative side of the rectifier circuit 12 is connected to an input terminal on the negative side of the inverter 20.
[0018]
The inverter 20 includes a first MOS field effect transistor (MOS-FET) 21 as a high (H) side switching means, and a second MOS-FET 22 as a low (L) side switching means. First and second drive circuits 23, 24, first and second control circuits 25, 26, time constant generation circuit 27, feedback control circuit 28, primary winding L11 of saturable current transformer CT1, and A first capacitor C11, for example an electrolytic capacitor and a first capacitor C11 The second capacitor C12 has a smaller capacity, and the second capacitor C12 and an inductor 29, such as a leakage transformer, constituting a resonance circuit.
[0019]
Hereinafter, the inverter 20 will be described in detail.
[0020]
The input terminal on the positive side of the inverter 20 is connected in series with the drain / source path of the MOS-FET 21 provided on the H side and the drain / source path of the MOS-FET 22 provided on the L side. T Connected to the input terminal on the negative side of the inverter 20 and between the capacitor C11 and the capacitor C12. series It is connected to the input terminal on the negative electrode side of the inverter 20 through the connection.
[0021]
A connection point between the first and second MOS-FETs 21 and 22 is a connection point between the capacitor C11 and the capacitor C12 via a series connection of the primary winding L11 of the saturable current transformer CT1 and the primary winding L21 of the inductor 29. Connected to. With this connection, the capacitor C11 and the capacitor C12 are provided in parallel to the MOS-FETs 21 and 22, respectively.
[0022]
Drive circuits 23 and 24 are connected to the gates of the MOS-FETs 21 and 22, respectively.
[0023]
The first drive circuit 23 includes a first secondary winding L12 of the saturable current transformer CT1 and resistors R21 and R22. The gate of the MOS-FET 21 is connected to the source of the MOS-FET 21 through a series connection of the resistor R21 and the first secondary winding L12 of the saturable current transformer CT1, and the MOS-FET 21 through the resistor R22. Connected to the source. A connection point between the secondary winding L12 and the resistor R21 is connected to the anode of the diode D21 of the first control circuit 25.
[0024]
The first control circuit 25 includes a diode D21, a Zener diode ZD21, resistors R23 and R24, an electrolytic capacitor C21, a capacitor C22, and an NPN transistor Tr21.
[0025]
The cathode of the diode D21 is connected to the collector of the NPN transistor Tr21 through a parallel connection of a Zener diode ZD21, a resistor R23, and an electrolytic capacitor C21. A parallel connection of the Zener diode ZD21, the resistor R23, and the electrolytic capacitor C21 serves as a first controlled impedance means. The Zener diode ZD21 has an anode connected to the NPN transistor Tr21 side and a cathode connected to the diode D21 side. The emitter of the NPN transistor Tr21 is connected to the source of the MOS-FET 21. The base of the NPN transistor Tr21 is a resistor R24 Are connected to the emitter of the NPN transistor Tr21 through a parallel connection of the capacitor C22 and to the cathode of the diode D22.
[0026]
The second drive circuit 24 includes a second secondary winding L13 of the saturable current transformer CT1 and resistors R31 and R32. The gate of the MOS-FET 22 is connected to the source of the MOS-FET 22 through a series connection of the resistor R31 and the second secondary winding L13 of the saturable current transformer CT1, and the MOS-FET 22 through the resistor R32. Connected to the source. The connection point between the secondary winding L13 and the resistor R31 is connected to the anode of the diode D31 of the second control circuit 26.
[0027]
The second control circuit 26 includes a diode D31, a resistor R33, an electrolytic capacitor C31, and an NPN transistor Tr31.
[0028]
The cathode of the diode D31 is connected to the source of the MOS-FET 22 through a series connection of the collector / emitter path of the NPN transistor Tr31 and the resistor R33, and is connected to the source of the MOS-FET 22 through the electrolytic capacitor C31. The electrolytic capacitor C31 and the resistor R33 are the second controlled impedance means.
[0029]
The feedback control circuit 28 includes resistors R41, R42, R43, R44, a capacitor C41, and an NPN transistor Tr41.
[0030]
The drain of the MOS-FET 21 is connected to the source of the MOS-FET 22 through a series connection of resistors R41 and R42.
[0031]
The connection point between the resistors R41 and R42 is connected to the source of the MOS-FET 22 via the capacitor C41 and to the base of the NPN transistor Tr41. The emitter of the NPN transistor Tr41 is connected to the source of the MOS-FET 22 via the resistor R44 and to the base of the NPN transistor Tr31 of the second control circuit 26. The collector of the NPN transistor Tr41 is connected to the collector of the PNP transistor Tr51 of the time constant generation circuit 27 via the resistor R43.
[0032]
The time constant generating circuit 27 includes resistors R51 and R52, a PNP transistor Tr51, a Zener diode ZD51, and electrolytic capacitors C51 and C52.
[0033]
The drain of the MOS-FET 21 is connected to the source of the MOS-FET 22 through a series connection of a resistor R51 and an electrolytic capacitor C51.
[0034]
The connection point between the resistor R51 and the capacitor C51 is connected to the source of the MOS-FET 22 via the emitter / collector path of the PNP transistor Tr51 and the electrolytic capacitor C52. The base of the PNP transistor Tr51 is connected to the cathode of the Zener diode ZD51. The anode of the Zener diode ZD51 is connected to the source of the MOS-FET 22. Of the PNP transistor Tr51 collector Is connected to the source of the MOS-FET 22 via the resistor R52 and to the base of the NPN transistor Tr21 of the first control circuit 25 via the resistor R25 and the anode / cathode path of the diode D22.
[0035]
One end of the secondary winding L22 of the inductor 29 is connected to one electrode of the discharge lamp 61, and the other end of the secondary winding L22 of the inductor 29 is connected to the other electrode of the discharge lamp 61.
[0036]
A capacitor C61 is connected between one electrode of the discharge lamp 61 and the other electrode. With such a connection, the discharge lamp 61 and the capacitor C61 constitute an output circuit 60.
[0037]
With such a configuration, the first and second drive circuits 23 and 24 use the first and second secondary windings L12 and L13 of the saturable current transformer CT1, respectively, for the MOS-FETs 21 and 22, respectively. By alternately applying an on-voltage to the control terminals, the MOS-FETs 21 and 22 are alternately turned on and off, respectively.
[0038]
The first and second control circuits 25 and 26 respectively have the impedances of the first and second control impedance means connected in parallel to the first and second secondary windings L12 and L13 of the saturable current transformer CT1. By controlling, the ON width by the first and second drive circuits 23 and 24 is independently controlled.
[0039]
The Zener diode ZD21, which is a voltage limiting element, is provided in the control impedance means of the first control circuit 25 and limits the voltage applied to the control impedance means so as not to exceed the limit voltage value.
[0040]
The feedback control circuit 28 prevents fluctuations in the output of the inductor 29 due to fluctuations in the power supply voltage of the rectifier circuit 12 when the starting voltage is generated and when the starting voltage is lit. Times Control circuit on the L side based on the voltage between the output terminals of the rectifier circuit 12 26 Is supplied with a control voltage Va at a control level.
[0041]
In the embodiment of the present invention, by setting the limiting voltage value of the voltage limiting element (Zener diode ZD21) to an appropriate value, the switching means (MOS-FET 22) on the low side is generated when the starting voltage is generated and when the discharge lamp 61 is lit. ) Can be made constant at the control level (control voltage Va) of the control circuit 26.
[0042]
The operation of this embodiment will be described below.
[0043]
First, when the switch SW 1 is turned on, the voltage of the AC power supply 11 is full-wave rectified by the rectifier circuit 12 and applied to the inverter 20. As a result, electric charges are accumulated in the electrolytic capacitors C11 and C12, and an on-voltage is applied to the gate of the MOS-FET 22 by a starting circuit (not shown). In this state, the MOS-FET 21 is off.
[0044]
At this point the time constant Occurrence The PNP transistor Tr51 of the circuit 27 is turned off, the NPN transistors Tr21 and Tr31 of the control circuits 25 and 26 are turned off, and control is performed from the connection point between the first secondary winding L12 of the saturable current transformer CT1 and the resistor R21. Since no current flows through the circuit 25 and current from the connection point between the second secondary winding L13 of the saturable current transformer CT1 and the resistor R31 does not flow into the resistor R33, the control circuits 25 and 26 The control impedance is set to a high value, so that the MOS-FETs 21 and 22 of ON / OFF frequency Is set to a high value, and a low level lamp preheating voltage is applied to the discharge lamp 61.
[0045]
When such a lamp preheating period elapses for about 1 second, the PNP transistor Tr51 of the time constant generating circuit 27 is turned on, the NPN transistors Tr21 and Tr31 of the control circuits 25 and 26 are turned on, and the first saturable current transformer CT1 is turned on. A current flows from the connection point of the secondary winding L12 and the resistor R21 to the control circuit 25, and a current from the connection point of the second secondary winding L13 of the saturable current transformer CT1 and the resistor R31 flows to the resistor R33. In this state, the control impedance of the control circuits 25 and 26 is set to a low value, whereby the on / off frequencies of the MOS-FETs 21 and 22 are set to a low value. Here, before the discharge lamp 61 is lit, the inductance of the primary winding L21 of the inductor 29 becomes a low value, and the inversion period of the output of the saturable current transformer CT1 becomes long. And The output voltage output from the first secondary winding L12 exceeds the Zener voltage of the Zener diode ZD21. In the state Zener diode ZD21 is on So The control impedance of the control circuit 25 is set to a lower value, the lamp power of the inductor 29 becomes 30 W or more, the output voltage reaches 400 V, and the discharge lamp 61 is lit. When the discharge lamp 61 is lit, the inductance of the primary winding L21 of the inductor 29 becomes a high value, the inversion period of the output of the saturable current transformer CT1 becomes long, and the output voltage output from the first secondary winding L12 is increased. The voltage is lower than the Zener voltage of the Zener diode ZD21, the Zener diode ZD21 is turned off, the control impedance of the control circuit 25 is set to a value lower than that immediately before lighting, and the feedback control circuit 28 sets the output voltage of the inductor 29 to an appropriate level. Controlled, the discharge lamp 61 is lit at an appropriate output.
[0046]
Hereinafter, detailed operation by turning on and off the MOS-FETs 21 and 22 will be described.
[0047]
When the MOS-FET 22 is turned on, the first period starts, and the resonance circuit including the inductor 29 and the capacitor C12 resonates in series. After the resonance current flows through the series circuit of the inductor 29 and the capacitor C12, the resonance voltage decreases and rectification occurs. The current from the circuit 12 flows through the series connection of the capacitor C11, the primary winding L21 of the inductor 29, the primary winding L11 of the saturable current transformer CT1, and the switching means 22, and the current flowing through the primary winding L11 is predetermined. When the value exceeds the value, the saturable current transformer CT1 is saturated, and the gate side of the MOS-FET 21 and the gate of the MOS-FET 22 are opposite to the first and second secondary windings L12 and L13 of the saturable current transformer CT1, respectively. Side electromotive force is generated, the MOS-FET 21 is turned on, and the MOS-FET 22 is turned off. . As a result, a second period is reached, and a current flows from the first MOS-FET 21 to the capacitor C11 due to the energy stored in the inductor 29. Thereafter, the charge stored in the capacitor C11 is released, and the primary winding L11 of the inductor 29 is released. A current flows through the primary winding L21 of the saturable current transformer CT1. As a result, the outputs of the drive circuits 23 and 24 are inverted, the switching means 22 is turned on, the switching means 21 is turned off, the process returns to the first period, and the same operation is repeated thereafter. As a result, a high frequency current flows in the primary winding L21 of the inductor 29, and a high frequency voltage is induced in the secondary winding L22 of the inductor 29.
[0048]
2 and 3 are graphs showing the relationship between the on / off frequency fa of the MOS-FETs 21 and 22 and the control voltage Va to the control circuit 26. FIG. 2 shows when the starting voltage is generated, and FIG. Is shown.
[0049]
In FIG. 2, when the starting voltage is generated, the on / off frequency fa of the MOS-FETs 21 and 22 becomes flat until the control voltage Va reaches a level at which the Zener diode ZD21 is turned on. The voltage Va is a level at which the zener diode ZD21 is turned on. Le When it exceeds, it falls at a predetermined inclination.
[0050]
On the other hand, at the time of lighting, the voltage of the secondary winding L12 is set so as not to exceed the voltage of the Zener diode ZD21, so that it becomes flat in the range shown in the graph.
[0051]
2 and 3, in order to set the control voltage Va to a constant value A (for example, 2 V) when the starting voltage is generated and when the lighting is turned on, the limit voltage value of the Zener diode ZD21 is set to an appropriate value to set the Zener diode ZD21. When the control voltage Va is the value A when the starting voltage is generated, the frequency fa can be set to an appropriate value. Thereby, the control level (control voltage Va) of the control circuit 26 that controls the low-side switching means (MOS-FET 22) can be made constant when the starting voltage of the discharge lamp 61 is generated and when the discharge lamp 61 is lit.
[0052]
4 and 5 are graphs showing the relationship between the lamp voltage (starting voltage value) VL of the discharge lamp 61 and the control power Va with respect to the lamp power WL when the starting voltage is generated. FIG. 4 shows the case where the Zener diode ZD21 is not provided in FIG. FIG. 5 shows a case where a Zener diode ZD21 is provided.
[0053]
Figure 4 When the Zener diode ZD21 is not provided, the lamp power WL increases at a constant rate with respect to the control voltage Va, but starts the discharge lamp 61. Ru Therefore, the target value for the lamp power WL can be achieved when the control voltage Va is 2V.
[0054]
In FIG. 4, when the Zener diode ZD21 is not provided, the starting voltage value VL Increases at a constant rate with respect to the control voltage Va, but the target value for starting the discharge lamp 61 is also relatively high, 400V, so that the control voltage Va is 2V to achieve the target of the starting voltage value VL. The control voltage Va is required to be 3V.
[0055]
In FIG. 5, when the Zener diode ZD21 is provided, the starting voltage value VL 4 rises at the same rate as in FIG. 4 with respect to the control voltage Va until the level at which the Zener diode ZD21 operates, but exceeds the level at which the Zener diode ZD21 operates at a rate higher than that in FIG. Rise You Therefore, when the control voltage Va is 2V, the target value 400V of the starting voltage value VL can be achieved.
[0056]
In such an embodiment of the invention, the control level of the control circuit 26 that controls the low-side switching means can be made constant when the starting voltage of the discharge lamp 61 is generated and when it is turned on. Ru Therefore, it is not necessary to set such a response (gain) of the control circuit 26 in a wide range, the starting voltage value can be made appropriate, and the light output during lighting can be made constant by fluctuations in the power supply voltage of the rectifier circuit. can do.
[0057]
Also figure 5 As shown in FIG. 5, by providing the Zener diode ZD21, the control level of the control circuit 26 can be lowered, and the efficiency of the circuit can be improved.
[0058]
FIG. 6 is a perspective view showing an illuminating device by a discharge lamp lighting device to which the embodiment of the invention of FIG. 1 is applied.
[0059]
In FIG. 6, a lighting device 401 has a discharge lamp 61 mounted between sockets 402 and 403, and a discharge lamp lighting device (a portion excluding the discharge lamp 61 and the AC power source 11 shown in FIG. 1) 10 is built therein. The discharge lamp lighting device 10 lights the discharge lamp 61.
[0060]
With such a structure, the embodiment of the invention of FIG. 1 can be applied to a lighting device.
[0061]
In the embodiment of the invention shown in FIG. 1, MOS-FETs are used as the first and second switching means. However, switching elements other than MOS-FETs, for example, ordinary NPN transistors are used. Also good.
[0062]
【The invention's effect】
According to the present invention, the control level of the control circuit that controls the low-side switching means can be made constant when the starting voltage of the discharge lamp is generated and when it is lit, so that the starting voltage value can be made appropriate. In addition, it is possible to make the light output during lighting constant by changing the power supply voltage of the rectifier circuit.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing an embodiment of a discharge lamp lighting device according to the present invention.
FIG. 2 is a graph showing the relationship between the on-off frequency of the MOS-FET of FIG. 1 and the start-up voltage generation of the control voltage to the L-side control circuit.
3 is a graph showing the relationship between the ON / OFF frequency of the MOS-FET of FIG. 1 and the lighting of a control voltage to the L-side control circuit.
4 is a graph showing a relationship between a starting voltage value of a discharge lamp and a control voltage with respect to lamp power when a Zener diode is provided in the control circuit of FIG. 1;
FIG. 5 is a graph showing the relationship between the starting voltage value of the discharge lamp and the control voltage with respect to the lamp power when no Zener diode is provided in the control circuit of FIG. 1;
6 is a perspective view showing an illumination device using a discharge lamp lighting device to which the embodiment of the invention of FIG. 1 is applied. FIG.
[Explanation of symbols]
11 AC power supply
12 Rectifier circuit
21,22 MOS-FET
23, 24 Drive circuit
25, 26 Control circuit
28 Feedback control circuit
29 Inductor
61 Discharge lamp
CT1 Saturable current transformer
ZD21 Zener diode

Claims (5)

A rectifying circuit that rectifies the output voltage of the AC power supply and outputs a DC voltage;
Are connected in series between output terminals of the rectifier circuit, Ri Do the high side and low side between the output terminals of the rectifier circuit respectively, the first and second field-effect transistor for performing a switching operation turned on and off alternately with each other When;
First and second capacitors connected in series between output terminals of the rectifier circuit, the first capacitor having a relatively large capacity and provided in parallel to the first field effect transistor; The second capacitor has a smaller capacity than the first capacitor and is provided in parallel with the second field-effect transistor;
The second capacitor and the resonance circuit are connected between a connection point of the first and second field effect transistors and a connection point of the first and second capacitors, and during the on period of the second field effect transistor. An inductor to form;
A saturable current transformer having a primary winding connected in series to the inductor;
An output circuit for supplying the discharge lamp with a high-frequency output obtained based on resonance of the inductor and the second capacitor;
By applying on-voltages alternately to the control terminals of the first and second field effect transistors using the first and second secondary windings of the saturable current transformer, respectively, the first and second First and second drive circuits for alternately turning on and off the field effect transistors ;
The current flowing from the output terminals of the first and second secondary windings to the first and second controlled impedance means connected in parallel to the first and second secondary windings of the saturable current transformer, respectively. First and second control circuits for controlling impedances of the first and second control impedance means by controlling presence / absence, and independently controlling on-width by the first and second drive circuits; ;
A feedback control circuit for supplying a control voltage to the second control circuit based on a voltage between the output terminals of the rectifier circuit, and preventing fluctuations in the output of the inductor due to fluctuations in the power supply voltage of the rectifier circuit; ;
A Zener diode provided in parallel with the control impedance means of the first control circuit, for controlling the switching frequency by changing the ON width of the first and second field effect transistors, wherein the preheating period In this case, the output frequency of the first secondary winding of the saturable current transformer exceeds the Zener voltage of the Zener diode, thereby increasing the switching frequency of the first and second field effect transistors and preheating. A Zener diode that is turned on after a lapse of time and operates so as to lower the control impedance of the first control circuit and lower the switching frequency of the first and second field effect transistors;
A discharge lamp lighting device comprising: A rectifying circuit that rectifies the output voltage of the AC power supply and outputs a DC voltage;
Are connected in series between output terminals of the rectifier circuit, Ri Do the high side and low side between the output terminals of the rectifier circuit respectively, the first and second field-effect transistor for performing a switching operation turned on and off alternately with each other When;
First and second capacitors connected in series between output terminals of the rectifier circuit, the first capacitor having a relatively large capacity and provided in parallel to the first field effect transistor; The second capacitor has a smaller capacity than the first capacitor and is provided in parallel with the second field-effect transistor;
The second capacitor and the resonance circuit are connected between a connection point of the first and second field effect transistors and a connection point of the first and second capacitors, and during the on period of the second field effect transistor. An inductor to form;
A saturable current transformer having a primary winding connected in series to the inductor;
An output circuit for supplying the discharge lamp with a high-frequency output obtained based on resonance of the inductor and the second capacitor;
By applying on-voltages alternately to the control terminals of the first and second field effect transistors using the first and second secondary windings of the saturable current transformer, respectively, the first and second First and second drive circuits for alternately turning on and off the field effect transistors ;
The current flowing from the output terminals of the first and second secondary windings to the first and second controlled impedance means connected in parallel to the first and second secondary windings of the saturable current transformer, respectively. First and second control circuits for controlling impedances of the first and second control impedance means by controlling presence / absence, and independently controlling on-width by the first and second drive circuits; ;
A feedback control circuit for supplying a control voltage to the second control circuit based on a voltage between the output terminals of the rectifier circuit, and preventing fluctuations in the output of the inductor due to fluctuations in the power supply voltage of the rectifier circuit; ;
A Zener diode provided in parallel with the control impedance means of the first control circuit, for controlling the switching frequency by changing the ON width of the first and second field effect transistors, wherein the preheating period In this case, the output frequency of the first secondary winding of the saturable current transformer exceeds the Zener voltage of the Zener diode, thereby increasing the switching frequency of the first and second field effect transistors and preheating. A Zener diode that is turned on after a lapse of time and operates so as to lower the control impedance of the first control circuit and lower the switching frequency of the first and second field effect transistors;
Comprising a discharge lamp lighting apparatus wherein the zener diode is characterized in that setting the Zener voltage of the Zener diode to work when not operating, the starting voltage generating during discharge lamp lighting. The discharge lamp lighting device according to claim 1, wherein an electrolytic capacitor is used as the first capacitor . A discharge lamp lighting device according to any one of claims 1 to 3;
A luminaire body that houses the discharge lamp lighting device;
An illumination device comprising: An instrument body;
A discharge lamp mounted on the appliance body;
The discharge lamp lighting device according to any one of claims 1 to 3, wherein the discharge lamp is lit.
An illumination device comprising:

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