JPH0765974A - Electronic stabilizer - Google Patents

Abstract

PURPOSE: To lessen and lighten an electronic ballast by transforming a pulse signal from a pulse width modulation special chip, turning on/off an FET ele ment for a switching regulator and feedbacking a detected current. CONSTITUTION: A signal supplied from a commercial power source 100 through a transformer T1 is supplied through the first bridge circuit BG1 to a switching regulator 104. Pulse transformers T3, T4 driven by a pulse width modulator 108 are used to supply a rectangular wave signal to a high-voltage discharge lighting circuit 106, while alternating turning on FET switching elements Q1, Q2, Q3, Q4. Voltage supplied to the circuit 106 is boosted up to four times with the opeartion of a diode and a capacitor. In the circuit 106, the voltage of a current-detecting resistor R14 is divided by resistors 4, 5 and the capacitor C8 to keep a supplied current constant and then supplied to a pulse width modulation special chip so as to keep an output current at a constant value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic ballast, and more particularly to an electronic ballast for supplying a voltage and current required for a lighting circuit by using a full bridge system.

[0002]

2. Description of the Related Art In order to keep a high-pressure discharge lamp lit by using a commercial power source, a high voltage is applied at the time of lighting, and after lighting, a constant voltage and current lower than the moment of lighting are continuously supplied. A device that can do this is required, but a ballast plays such a role. A conventional electric ballast uses a coil and a capacitor to light a high pressure discharge lamp.

When the conventional ballast is used, the coil becomes bulky and becomes large and heavy, and of course, there is a problem that the efficiency becomes low.

That is, in order to obtain high efficiency for lighting the high-pressure discharge lamp in the conventional electric ballast, it is necessary to make the ballast large and heavy, so that it is necessary to make the ballast smaller and lighter. It was

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic ballast capable of reducing loss and increasing efficiency by applying high frequency switching, and satisfying miniaturization and weight saving. That is.

[0006]

To achieve the above object, an electronic ballast according to the present invention comprises an input filter and a smoothing circuit for inputting power from a commercial power supply and supplying a smooth filtered power supply, and the input. A switching regulator for generating a rectangular wave supplied with power from a filter and a smoothing circuit, a lighting circuit of a high pressure discharge lamp for inputting the rectangular wave from the switching regulator and lighting a high pressure discharge lamp, and the input A pulse width modulation unit for generating a predetermined pulse width modulation signal using a signal that is supplied with power from a filter and a smoothing circuit and is proportional to a current value flowing in the switching regulator, and a pulse from the pulse width modulation unit. A driving circuit for transforming the width modulation signal to drive the switching regulator is provided.

[0007]

[Operation] A drive system for transforming a pulse signal from a pulse width modulation dedicated chip to turn on / off a FET switching element of a switching regulator, and a current detected by using a current detection resistor and a resistor and a capacitor which are voltage distribution elements. And a method for feeding back the ballast, to reduce the size, weight and efficiency of the ballast.

[0008]

The present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the structure of an electronic ballast according to the present invention. The schematic structure of the device according to the present invention will be described below.

The commercial power supply 100 is input to the input filter and smoothing circuit 102. Power is supplied from the input filter and smoothing circuit 102 to the switching regulator 104 and the pulse width modulator 108. The output signal from the pulse width modulator 108 is input to the drive circuit 110. The output signal of the driving circuit 110 is input to the switching regulator 104. The rectangular wave generated from the switching regulator 104 is input to the high pressure discharge lamp lighting circuit 106, and is obtained by dividing the voltage corresponding to the current flowing through the high pressure discharge lamp lighting circuit in response to the rectangular wave from the switching regulator 104. The generated voltage signal is input to the pulse width modulation unit 108.

FIG. 2 is a detailed circuit diagram of the electronic ballast according to the present invention, and FIG. 3 is a detailed circuit diagram of the high pressure discharge lamp lighting circuit. The structure and operation of the electronic ballast according to the present invention will be described with reference to FIGS. 2 and 3.

Power is supplied from the commercial power source 100 to the input filter and smoothing circuit 102 through the transformers T1 and T2. The input filter and smoothing circuit 102 includes capacitors C1, C2 and C3 for filtering and bridge circuits BG1 and BG2 for smoothing.

The switching regulator 104 receives the power supplied from the first bridge circuit BG1 and is composed of a capacitor C4, FET (Field Effect Transistor) switching elements Q1, Q2, Q3, Q4 and a resistor R14. One terminal of the capacitor C4 is connected to the output one terminal of the first bridge circuit BG1 and the other terminal is connected to the ground terminal.

The drains of the FET switching element Q1 and the FET switching element Q3 are connected to the output one side terminal of the first bridge circuit BG1. Source of FET switching element Q1 and FET switching element Q4
Is connected to the first terminal 1 of the high pressure discharge lamp lighting circuit 106, and the source of the FET switching element Q3 and the drain of the FET switching element Q2 are connected to the second terminal 2 of the high pressure discharge lamp lighting circuit 106. Has been done. One terminal of the resistor R14 is connected to the other output one terminal of the first bridge circuit BG1 connected to the ground, and the other one terminal is connected to the sources of the FET switching element Q2 and the FET switching element Q4. Has been done.

The high pressure discharge lamp lighting circuit 106 shown in FIG. 3 receives the rectangular wave signal output from the switching regulator 104 through the first and second terminals 1 and 2, and receives the choke coil L1 and capacitors C13, C14 and C15. ,
C16, diodes D3, D4, D5, D6, transformer T
5, a spark gap G1 and a lamp. One side terminal of the choke coil L1 is connected to the first terminal 1 of the high pressure discharge lamp lighting circuit 106, and the other side terminal is connected to the capacitor C13 and one side terminal of the lamp. One terminal of the capacitor C14 is connected to the other terminal of the capacitor C13, the cathode terminal of the diode D3 and the diode D4.
Is connected to the anode terminal of. The cathode terminal of the diode D4 is connected to the anode terminal of the diode D5 and one terminal of the capacitors C15 and C16. The other terminal of the capacitor C14 and the anode terminal of the diode D6 are connected to the cathode terminal of the diode D5.

The second terminal 2 of the high pressure discharge lamp lighting circuit 106 is connected to the anode terminal of the diode D3 and one terminal of the capacitor C16. The other terminal of the capacitor C16 is connected to the terminal of the capacitor C15.
The other terminal of the capacitor C15 is connected to the cathode terminal of the diode D6 and the one terminal of the spark gap G1.

The other side terminal of the spark gap G1 is connected to one side terminal of the primary winding of the transformer T5, and the other side terminal of the primary winding of the transformer T5 is connected to the second terminal 2 and It is connected to one terminal of the secondary winding of the transformer T5. Transformer T
The other side terminal of the secondary winding 5 is connected to the other side terminal of the lamp.

In FIG. 2, the drive circuit 110 includes transformers T3 and T3.
4, resistors R8 to R18, diodes D1 and D2, capacitors C11 and C12, and Zener diodes ZD1 to ZD
It is composed of D8. One terminal of the primary winding of the transformer T3 is connected to the output terminal of the pulse width modulator 108 and the anode terminal of the diode D1. The cathode terminal of the diode D1 is connected to one terminal of the capacitor C11 and one terminal of the resistor R8.

The common voltage source Vcc from the second bridge circuit BG2 is a capacitor C11, a resistor R8 and a transformer T.
3 is connected to the other one side terminal of the primary winding. Resistance R
Reference numeral 10 is connected to one terminal of the first secondary winding of the transformer T3. On the other side of the resistor R10, the anode terminal of the Zener diode ZD1 and the switching regulator 10 are provided.
4 FET switching element Q1 is connected to the gate.

The cathode terminal of the Zener diode ZD1 is connected to the cathode terminal of the Zener diode ZD2.
One terminal of the resistor R15 is connected to the Zener diode ZD1.
Of the Zener diode ZD2, and the other one terminal thereof is connected to the anode terminal of the Zener diode ZD2.

The other one-side terminal of the first secondary winding of the transformer T3 is the anode terminal of the Zener diode ZD2 and the FET switching element Q1 of the switching regulator 104.
Is linked to the source. One terminal of the resistor R11 is connected to one terminal of the second secondary winding of the transformer T3. The other side terminal of the resistor R11 is a Zener diode Z.
It is connected to the anode terminal of D3 and the gate of the FET switching element Q2 of the switching regulator 104.

The cathode terminal of the Zener diode ZD3 is connected to the cathode terminal of the Zener diode ZD4.
One terminal of the resistor R16 is connected to the Zener diode ZD3.
Of the Zener diode ZD4, and the other one terminal thereof is connected to the anode terminal of the Zener diode ZD4. Transformer T
The other one side terminal of the second secondary winding of No. 3 is the anode terminal of the Zener diode ZD4 and the switching regulator 10.
4 is connected to the source of the FET switching element Q2.

One terminal of the primary winding of the transformer T4 is connected to the output terminal of the pulse width modulator 108 and the anode terminal of the diode D2. The cathode terminal of the diode D2 is connected to one terminal of the capacitor C12 and one terminal of the resistor R9. One terminal of the resistor R12 is connected to one terminal of the first secondary winding of the transformer T4. Resistance R12
The other side terminal is connected to the anode terminal of the Zener diode ZD5 and the gate of the FET switching element Q3 of the switching regulator 104. The cathode terminal of the Zener diode ZD5 is connected to the cathode terminal of the Zener diode ZD6. One side terminal of the resistor R17 is connected to the anode terminal of the Zener diode ZD5, and the other side terminal is connected to the anode terminal of the Zener diode ZD6.

The other one-side terminal of the first secondary winding of the transformer T4 is the anode terminal of the Zener diode ZD6 and the FET switching element Q3 of the switching regulator 104.
Is linked to the source. One terminal of the resistor R13 is connected to one terminal of the second secondary winding of the transformer T4. The other side terminal of the resistor R13 is a Zener diode Z.
It is connected to the anode terminal of D7 and the gate of the FET switching element Q4 of the switching regulator 104. The cathode terminal of the Zener diode ZD7 is connected to the cathode terminal of the Zener diode ZD8. Resistance R1
One side terminal 8 is connected to the anode terminal of the Zener diode ZD7, and the other side terminal 8 is connected to the anode terminal of the Zener diode ZD8. Second of transformer T4
The other side terminal of the secondary winding of the zener diode ZD8
FE of switching regulator 104
It is connected to the source of the T switching element Q4.

The electronic ballast according to the present invention constructed as described above operates as follows.

The signal supplied from the commercial power source 100 through the transformer T1 is filtered by the capacitors C1, C2 and C3, smoothed by the first bridge circuit BG1 and supplied to the full-bridge switching regulator 104. The FET switching element Q1 and the FET are driven by the pulse transformer T3 and the pulse transformer T4 driven by the pulse width modulator 108.
While the switching element Q2, the FET switching element Q3 and the FET switching element Q4 are alternately turned on, a rectangular wave signal is supplied to the high pressure discharge lamp lighting circuit 106 through the first terminal 1 and the second terminal 2.

The voltage supplied to the high pressure discharge lamp lighting circuit 106 is boosted four times by the action of the diodes D3, D4, D5 and D6 and the capacitors C13, C14, C15 and C16, and then lit to the lamp through the spark gap G1. The voltage is re-boosted to the required voltage by the pulse transformer T5 of FIG.

Then, in order to keep the current supplied to the high-pressure discharge lamp lighting circuit 106 constant, the voltage of the current detection resistor R14 is divided by the resistors R4, R5 and C8, and then the pulse width modulation dedicated chip is provided. The supplied output current is maintained at a constant value.

[0029]

As described above, the electronic ballast according to the present invention transforms the pulse signal from the pulse width modulation dedicated chip,
It is configured to have a driving method of turning on / off the FET element of the switching regulator and a method of feeding back the current detected by using the current detection resistor R14, the resistors R4 and R5 which are voltage distribution elements, and the capacitor C8. Therefore, the present invention is effective in reducing the size, weight and efficiency of the ballast.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of an electronic ballast according to the present invention.

FIG. 2 is a detailed circuit diagram of an electronic ballast according to the present invention.

FIG. 3 is a detailed circuit diagram of a high pressure discharge lamp lighting circuit applied to the present invention.

[Explanation of symbols]

 100 Commercial Power Supply 102 Input Filter and Smoothing Circuit 104 Switching Regulator 106 High-Pressure Discharge Lamp Lighting Circuit 108 Pulse Width Modulation Unit 110 Drive Circuit

Claims (10)

[Claims] 1. An input filter and a smoothing circuit for inputting commercial power and supplying a smooth-filtered power source, a switching regulator for receiving a power from the input filter and the smoothing circuit to generate a rectangular wave, and the switching circuit. A high voltage discharge lamp lighting circuit for lighting the high pressure discharge lamp by inputting the rectangular wave from the regulator, and controlling a signal that is supplied with power from the input filter and the smoothing circuit and is proportional to the current value flowing to the switching regulator. A pulse width modulation unit for generating a predetermined pulse width modulation signal as a signal, and a drive circuit for transforming the pulse width modulation signal from the pulse width modulation unit and driving the switching regulator. An electronic ballast. 2. The drive circuit includes a first pulse transformer for transforming a first output signal from the pulse width modulator, and a first pulse transformer for transforming a second output signal from the pulse width modulator. A two-pulse transformer, a primary winding protection circuit for removing residual energy accumulated in the primary windings of the first and second pulse transformers, and a secondary winding of the first and second pulse transformers The electronic ballast according to claim 1, further comprising an overvoltage protection circuit for preventing an excessive voltage in the output voltage induced in the winding. 3. The primary winding protection circuit includes a first capacitor connected to a power source from the input filter and the smoothing circuit, a first resistor connected in parallel with the first capacitor, and the first capacitor. And a first diode having a positive terminal connected to one terminal of each of the second pulse transformers and a negative terminal connected to a parallel circuit of the first capacitor and the first resistor. The electronic ballast described in 2. 4. The switching regulator includes a second capacitor whose one terminal is connected to the output voltage terminal from the input filter and the smoothing circuit, and the other one terminal is connected to the ground, and one of the second capacitors. First switching means connected to a side terminal; third switching means connected to one side terminal of the second capacitor; second switching means connected in series to the third switching means; A fourth switching means connected in series to the switching means; and a first switching element connected to the second and fourth switching means.
A second for applying a voltage corresponding to a current flowing through the high pressure discharge lamp lighting circuit through a third switching means so as to be inputted as a control signal of the pulse width modulation section.
The electronic ballast according to claim 1, further comprising a resistor. 5. The first and second switching means, wherein the gate has a first state output signal of the first pulse transformer,
The source is the second state output signal of the first pulse transformer,
5. The electronic ballast according to claim 4, wherein the drains are field effect transistors connected to the power supply from the input filter and the smoothing circuit and the second terminal of the high pressure discharge lamp lighting circuit, respectively. 6. The third and fourth switching means, wherein the gate has a first state output signal of the second pulse transformer,
The source is the second state output signal of the second pulse transformer,
5. The electronic ballast according to claim 4, wherein the drains are field effect transistors connected to the power supply from the input filter and the smoothing circuit and the first terminal of the high pressure discharge lamp lighting circuit, respectively. 7. The high-pressure discharge lamp lighting circuit receives a choke coil connected in series to a first terminal of the high-pressure discharge lamp lighting circuit and a rectangular wave generated from the switching regulator to light the high-pressure discharge lamp. A step-up circuit for generating a required predetermined high voltage, one side terminal of the primary winding is connected to an output terminal of the step-up circuit, and another side terminal is connected to one side terminal of the secondary winding. The electronic ballast according to claim 1, wherein the other side terminal of the cage secondary winding comprises a transformer connected to the side terminal of the lamp. 8. The booster circuit includes a third capacitor having one side terminal connected to the choke coil, a fourth capacitor having one side terminal connected to another side terminal of the third capacitor, and an anode. A second diode whose terminal is connected to the other side terminal of the third capacitor, an anode terminal connected to the second terminal of the high-pressure discharge lamp lighting circuit, and a cathode terminal connected to the anode terminal of the second diode. Third
A diode and a fourth terminal in which a cathode terminal is connected to the other side terminal of the fourth capacitor and an anode terminal is connected to a cathode terminal of the second diode.
A diode, a fifth diode whose anode terminal is connected to the cathode terminal of the fourth diode, one side terminal connected to the cathode terminal of the fifth diode, and another side terminal connected to the cathode terminal of the second diode Fifth done
A capacitor, a sixth capacitor having one side terminal connected to the other one side terminal of the fifth capacitor, another side terminal connected to a second terminal of the high pressure discharge lamp lighting circuit, and one side terminal of the fifth capacitor The cathode terminal of the five-diode comprises a spark gap, the other side terminal of which is connected to the one side terminal of the primary winding of the transformer.
Electronic ballast described in. 9. The electronic ballast as claimed in claim 7, further comprising a seventh capacitor connected in parallel to the choke coil to further reduce the size of the choke coil. 10. The electronic ballast according to claim 7, further comprising an eighth capacitor connected in series to the choke coil, so that the choke coil can be further downsized.