KR100372015B1 - Electronic ballast for high intensity discharge lamp - Google Patents

Abstract

Lamp matching unit 400 of the self-contained electronic ballast for a high-voltage discharge (HID) lamp of the present invention includes the resonant capacitor (C12A, C12B, C13, C14) and the inductor (T4), the inverter unit 500, 500 ' ) Is turned on / off by the drive transformer T5 having one winding electrically connected to the resonant inductor T4 and whether the other winding of the drive transformer is energized, and triggers the resonance circuit of the lamp matching unit to generate a high frequency output. Trigger elements Q1 and Q2 for generating, start circuits C17, R6 and DIAC for operating the trigger element when the lamp is started, and circuits R22 and D10 for stopping the operation of the start circuit after the lamp is turned on. The power control unit 600, 600 ′ includes an output detector T3 and 710 for detecting an output signal to a lamp, and compares the value detected by the output detector with an input current and compares the input value with the input voltage. Multiplier 720 multiplied by the power calculated by the multiplier And it includes a drive transformer (T5) pulse width adjusting section 670 to a plurality of pulses having a predetermined pulse width to be applied to the lamp through the lamp at the time of start-up in response to the comparison result of the reference value. Therefore, according to the present invention, a high-voltage pulse having a sufficient pulse width is applied several times at the time of lamp startup, so that reliable lighting can be achieved regardless of the type of the HID lamp.

Description

Electronic ballast for high pressure discharge lamp {ELECTRONIC BALLAST FOR HIGH INTENSITY DISCHARGE LAMP}

The present invention relates to an electronic ballast for High Intensity Discharge (HID) lamps, and more particularly to a self-contained electronic ballast with improved protection circuit function and smooth starting.

Electronic ballasts contain a starting semiconductor element in the ballast, which preheats the electrode with its switching action or electrode heating winding and starts the lamp by the semiconductor switching action, while the lamp is heated by the lamp current and the electrode heating winding during lighting. As the ballast used in the circuit method, there are self-excited equations oscillated by its own LC resonant circuit, and the equations relating to the present invention using a separate oscillator.

Electronic ballasts have several advantages over conventional ballasts, but they are weak in voltage fluctuations and surge voltages, so they must have a built-in protection circuit and require special measures at start-up.

On the other hand, the high-pressure discharge lamp has a high voltage, such as mercury lamp, high-pressure sodium lamp, metal halide lamp, and the inside of the tube becomes a high-temperature plasma state when lighting. In order to create such a high pressure discharge condition, an electronic ballast is mainly used in recent years, and there is a self-supporting electronic ballast for a high pressure discharge lamp such as PCT Publication No. WO99 / 51066.

First, the electronic ballast of the above publication will be described with reference to FIG.

The conventional HID electronic ballast as shown in FIG. 1 includes an input power supply unit 1, a converter unit 2, an inverter unit 3, an output matching unit 4, a buffered DC power supply unit 5, and a power control unit ( 6) and the gate transformer section 7.

The input power supply 1 is composed of a fuse FUSE, a varistor ZNR, a capacitor C301-C303, and a transformer TR1 so as to stabilize the voltage of the AC power, and stabilizes the power supply voltage.

The AC voltage stabilized in the input power supply is applied to the converter section 2 of the next stage, rectified by the bridge diodes D301-D304, smoothed by the choke coil TR2 and the capacitor C304, and rectified. DC current is applied to the inverter section 3 which is the next stage.

The inverter unit 3 applies the voltage charged by the first and second switching transistors K1 and K2 to which the rectified DC power is applied and the rectified DC power to the diak to turn on the diac D311. The second capacitor C313 (when the diamond is turned on, the switching transistor K2 is also turned on), and the first and second gate waveform shaped integrated circuits IC1 to which the resonance signal detected by the gate transformer TR5 is applied. IC2). That is, at the start of the lamp, if the diaak D311 is turned on by the voltage charged in the second capacitor C313, the second switching transistor K2 is switched and the free resonance signal is output to the output matching section 4. Is here. The gate transformer TR5 detects a signal of the resonant circuit and applies it to the first and second gate waveform shaping integrated circuits IC1 and IC2. The integrated circuit again applies an applied signal to the gate of the first switching transistor K1 to pass the control voltage in the gate protection zener diode to the voltage source and the current source, and positively goes to the gate until the reflected signal voltage increases. A gate voltage signal is applied, and when the voltage decreases, the first transistor is turned on as the potential on the gate is higher than the potential on the gate transformer TR5, thereby reducing the gate potential to the negative gate potential to the potential of the voltage source. As a result, since the first and second switching transistors are switched in synchronization with the reflected signal, their output causes resonance and continuously oscillates. Resistor R302 and R303 are used as an initial signal generator together with the diaak D311 and capacitor C313, and resistors R304 and diode D312 eliminate the initial signal generation. The capacitors C311 and C312 suppress the voltage rise rates of the switching transistors K1 and K2.

The output matching section 4 has a resonant coil TR4 for determining the time constant, first to third resonant capacitors C307-C309, and a winding ratio matching the tube voltage (when the voltage is high, the winding ratio is high). The output transformer TR3 returns the generated reflected power to the buffer DC power supply unit 5 when the output is not in a resonance state.

The buffer DC power supply unit 5 includes first and second diodes D307 and D308 for inputting the reflected power generated from the output matching unit 4, and third and third sources in which the input power is charged to reduce the ripple component of the DC voltage. Fourth condenser (C305, C306), third and fourth diodes (D305, D306) for compensating the charging voltage to the third and fourth capacitors through the first and second diodes while the DC voltage is at a low level. Is done.

The power control unit 6 includes a first operational amplifier U2, a first resistor R315, a second operational amplifier U1, a second resistor R307, and a third resistor R306. The first operational amplifier U2 detects the value detected from the first DC current detection resistor R301 and the second and third DC voltage detection resistors R308 and R309 in the output control integrated circuit IC3. The current of the gate transformer TR5 is finally controlled by controlling the second current source A2 by a value multiplied by the calculated value. The controlled current is converted into a voltage in the first resistor R315, and the second operational amplifier U1 calculates the voltage with a reference voltage. The calculated result is output to the second resistor R307, and the output value is set as the power setting value in the third resistor R306 and input to the first operational amplifier U2.

In addition, the power control unit 6 includes a first comparator U3, a fourth resistor R311, a second comparator U4, a fifth resistor R314, a first switch SW1, and a third comparator U5. It further includes. The detection value of the temperature sensor is input to the first comparator U3, and the comparison value of the first comparator U3 is set by the fourth resistor R311. If the detection temperature is higher than the set value in the first comparator U3, the output of the first operational amplifier U2 is cut off. In addition, the detection value of the photosensor is input to the second comparator U4, the comparison value of the second comparator U4 is set by the fifth resistor R314, and the detected external illuminance is the second comparator U4. If it is higher than the set value in, the output of the first operational amplifier U2 is cut off. In addition, when the signal of the first switch SW1 is input, the output blocking of the first operational amplifier U2 is removed. In addition, since the value of the current controlled by the second current source A2 is changed to the voltage at the first resistor R315, the voltage value is compared with the reference voltage by the third comparator U5, so that a large amount of current When the output of the first operational amplifier (U2) is cut off.

In addition, the power control unit 6 includes a timer for interrupting the output of the first operational amplifier when the lamp does not light up within the desired re-lighting time, and a sixth resistor R316 and a sixth resistor for determining a time constant for setting the time. 5 further includes a condenser C315 and an undervoltage circuit breaker that blocks the output of the first operational amplifier when the power supply voltage is small.

The gate transformer TR5 of the gate transformer unit 7 detects the resonance signal from the output matching unit 4 and applies the detected signals to the first and second gate waveform shaping integrated circuits IC1 and IC2.

Therefore, according to the prior art as described above, the switching transistor K2 is initially switched by the initial start-up units C313, D311, R302, and R303 of the inverter unit 3 so that the resonant circuit C307- of the output matching unit 4 is switched. The free resonance of C309 and TR4 is started, and when the start is made, the initial signal is removed by the initial signal removing units R304 and D312, and the output matching unit lights the lamp while continuously resonating at the disclosed resonance frequency.

The reflected power generated when the output of the output matching section 4 is not in the resonance state is controlled by the third and fourth capacitors C305 by the first and second diodes D307 and D308 of the buffer DC power supply section 5. , C306 is reflected, and the charging voltage is compensated by the third and fourth diodes D305 and D306. In addition, the output current is detected by the resistor R315 to set the desired output current, and compared with the signal detected by the input power detectors R301, R308, R309, and multiplier to control the gate transformer TR5. do.

However, among the HID lamps, a lamp with a built-in starter can be lit by a short pulse of about 600-800V, but a pulse train having a voltage of about 1.5-2kV, such as a metal halide lamp without a built-in starter, is used. The lamp can be turned on with the approval of. In addition, in the case of metal halide which does not have a built-in starter, it may not be lit when the pulse width is narrow (for example, less than 5 ms), and several high voltage pulses having a sufficient pulse width at start-up are applied. You may have to. As in the case of the prior art, when starting by the starter circuits C313, D311, R302, and R303 with only the charging voltage of the capacitor C313, smooth lighting may not be achieved depending on the type of lamp. (See Figure 1).

In addition, in the case of the prior art, there is no countermeasure against the immediate protection of the circuit in the case of the constant power function of the output signal, the protection of the circuit in the event of lamp failure, surge voltage, or the like. Therefore, there was a problem that the protection of the ballast is not enough.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a first object of the present invention is to apply a high-voltage pulse having a sufficient pulse width at the start of a lamp several times so that reliable lighting can be achieved regardless of the type of the HID lamp. To provide a ballast.

Further, a second object of the present invention is to provide a stabilizer which further strengthens the electrostatic power function of an output signal and exhibits a protective function immediately in case of lamp failure or surge voltage.

In addition, a third object of the present invention is to provide a stabilizer that has been improved to correct the phase of the input current to prevent unnecessary oscillation.

In addition, a fourth object of the present invention is to provide a stabilizer in which the protection circuit is improved so that it is possible to set a delay time at the time of re-lighting and a time for the re-lighting attempt.

Further objects and effects of the present invention will become more apparent from the following detailed description of the invention described with reference to the accompanying drawings.

1 is a circuit diagram of a conventional electronic ballast for a high-pressure discharge lamp.

2 is a circuit diagram of an electronic ballast for a high-pressure discharge lamp according to the first embodiment of the present invention.

3 is an example of the driver IC of FIG. 2;

4 is an example of the power control unit IC of FIG.

5 is a circuit diagram of an electronic ballast for a high-pressure discharge lamp according to a second embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

1 input power supply 2 converter 3 inverter

4 output matching unit 5 buffer DC power supply unit 6 power control unit

7: gate transformer

100: input power supply 200: rectifier

300, 300 ': DC buffer part 400: lamp matching part

500: inverter 600, 600 ': power control unit

610: regulator 620: reference voltage generator

630: input overvoltage detector 640: temperature detector

650: re-lighting time setting unit 660: reference voltage setting unit

670: pulse width adjusting unit 700: hybrid IC

710: output detector 720: multiplier

730: ignition time control unit 740: drive transformer output control unit

750: the current detecting unit

An electronic ballast, which is an aspect of the present invention for achieving the above object, rectifies an input AC signal and supplies a DC voltage, and receives a voltage applied from the rectifier and oscillates at a given resonance frequency. A lamp matching unit 400 to turn on the lamp, an inverter unit 500 and 500 'generating resonance of the lamp matching unit by receiving the rectified voltage from the rectifying unit, and a power control unit 600 and 600' controlling the inverter unit. An electronic ballast for a high-pressure discharge lamp including a), the lamp matching unit 400, the resonance capacitor (C12A, C12B, C13, C14) and the inductor (T4), the inverter unit (500, 500 ') ) Is turned on / off by a drive transformer T5 in which one winding is electrically connected to the resonant inductor T4, and whether the other winding of the drive transformer is energized. Trigger elements Q1 and Q2 for triggering and generating a high frequency output, start circuits C17, R6, and DIAC for operating any one of the trigger elements when the lamp is started, and after the lamp is turned on Circuits (R22, D10) for stopping operation, wherein the power control units (600, 600 ') are detected by the output detectors (T3, 710) for detecting the output signal to the lamp, and by the output detector (s). A multiplier 720 which compares the calculated value with the input current and multiplies the compared value with the input voltage, and the drive transformer T5 at the start of the lamp according to a comparison result of the power value calculated by the multiplier and the reference value. It is characterized in that it comprises a pulse width adjustment unit 670 to be applied to the lamp a plurality of pulses having a predetermined pulse width through).

Preferably, the triggering circuit is initially charged by the supply voltage of the rectifying unit through a resistor R6 connected in series and the charged voltage is transmitted to any one of the trigger elements Q1 through the DIAC. Or a first charging capacitor C17 applied to the control terminal of Q2), wherein the circuit for stopping the operation of the starting circuit includes a resistor R22 that discharges the charging voltage of the capacitor C17 after lighting. It characterized by including).

Also, preferably, the pulse width adjusting unit 670 may include a power value of the second charging capacitor C26 and the multiplication circuit, which are charged by an effective value of a signal of another winding of the one side of the drive transformer T5. The first switching element (Q4) for switching the charge / discharge of the second charging capacitor by the comparison result of the reference value is made, More preferably, the pulse width adjustment unit 670, the drive transformer A signal of another winding of one side of T5 is applied to the second charging capacitor C26 through the constant voltage diode ZD1, and the switching element is turned on / off according to a result of comparing the power value of the multiplication circuit with a reference value. By turning off, the power of the signal flowing through the drive transformer T5 may be maintained at a predetermined size.

Also, preferably, the power control unit 600, 600 ′ may include an input overvoltage detector 630 including a third charging capacitor C20 electrically coupled to the input terminal P3 and the constant voltage diode TVS. The drive transformer output adjusting unit 740 further includes a second switching element SCR connected to an output side of the drive transformer T5, and the input overvoltage detector 630 is configured to be input at startup. An overvoltage is transmitted to the third charging capacitor through the constant voltage diode (TVS) to charge the third charging capacitor, and the voltage charged in the third charging capacitor turns on the second switching element. The pulse width adjusting section is operated more reliably, and after lighting, the pulse width adjusting section is in an inoperative state.

Further, preferably, the comparison between the power value of the multiplication circuit and the reference value includes: a comparator (Q103) in which an output of the multiplication circuit is connected to the non-inverting stage input side, and a circuit 660 for setting the reference value is connected to the inverting stage input side The output of the comparison circuit 660 is again made by the phase correction circuits R12 and C24 connected to the power input terminal P1.

Also, preferably, the power control unit further includes a provisional current detection unit 750 connected to the output current detection unit 710, and the provisional current detection unit 750 detects a provisional current when the lamp is disabled. At this time, the third switching device T102 is turned on to cut off the supply of IC operating power to stop the operation of the power control unit.

In addition, preferably, the power control unit further includes a re-lighting time setting unit 650 including fourth and fifth charging capacitors C21 and C28, and an output terminal of the drive transformer output adjusting unit 740. Is connected to the fourth charging capacitor C21, is charged when the lamp is 'on' and discharged when the lamp is 'off', and the pulse is maintained in a constant voltage while the output of the drive transformer T5 is maintained during charging. It is characterized by setting the re-light delay time by preventing the start-up circuit, the start circuit (C17, R6, DIAC) is connected to the ground through the fourth switching element (T101), the control terminal of the fourth switching element Is connected to the fifth charging capacitor C28 which sets the ignition time upon re-lighting through the ignition time control unit 730, and stops the operation of the starting circuit if the lighting is not successful within a predetermined time. Key is characterized in that.

Hereinafter, a first embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is an overall circuit diagram of the electronic ballast for a high voltage discharge lamp according to the first embodiment of the present invention. FIG. 3 is an example of the driver IC (K01) 700 of FIG. 2, and FIG. 4 is the power control unit IC of FIG. It is an example of (K02).

As shown in FIG. 2, the electronic ballast according to the first embodiment of the present invention includes an input power supply unit 100, a rectifying unit 200, a buffer DC power unit 300, a lamp matching unit 400, and an inverter unit 500. ) And a power control unit 600.

The input power supply unit 100 receives two-phase AC power, which is a general AC power source, through two terminals WH, BL, and the like. The alternating current is filtered and stabilized again by a filter circuit consisting of three capacitors C1-C3 through a parallel circuit of the capacitor C1 and transformer T2 functioning as a filter through the fuse FUSE. The power stabilized by the filter circuit is applied to the rectifier 200 which is the next stage through the input transformer T1. Since the rectifier 200 is full-wave rectified by the bridge diode D1, the full-wave rectified voltage is applied to the terminals P1 and P2. Meanwhile, the rectified voltage is smoothed by the diode D2 and the smoothing capacitor C7. In addition, the lower potential terminal P2 becomes one end of the parallel circuit of the current detecting resistor R1 and the diode D3 connected in series, and the other end P6 of the parallel circuit and the upper potential terminal ( The rectified voltage and the high frequency noise between P1) are preferably filtered again by the noise filters C5 and C6. The next stage, the buffer DC power supply unit 300, the lamp matching unit 400 and the inverter unit 500 is connected to the noise filter circuit.

As in the prior art, the buffer DC power supply unit 300 receives the reflected power generated from the output matching unit 400 through the connection terminal P9, and the input power of the diodes D6 and D7 is charged to ripple the DC voltage. Condenser C8, C9 for reducing components, and other diodes D4, D5 for compensating the charging voltage to the capacitor through the diodes with the DC voltage at a low level.

The output matching section 4 includes resonant capacitors C12A, C12B and C13 for determining time constants connected to the connection terminal P9 and a resonant coil T4 connected to the other end P8 of the resonant capacitor C13. And an output transformer T3 having a winding ratio matching the tube voltage connected to the connection terminal P8 and returning the generated reflected power to the buffer DC power supply unit 5 when the output is not in a resonance state. The output transformer T3 is connected to one end P10 of the lamp through the resonant capacitor C14. The series resistance circuits R2 and R3 and the series circuits of the resistors R4 and diodes D8 and D9 are connected in parallel to both ends of the lamps P9 and P10. The lamp matching section is connected to the inverter section 500 which is the next stage through the contacts P1, P6 and P7.

The contacts P1 and P8 of the inverter section 500 are connected to the sources and drains of the MOSFETs Q1 and Q2 respectively serving as trigger elements of the inverter section, and the other input terminals of both trigger elements Q1 and Q2 are connected at the contacts P5. At the same time, one side winding of the drive transformer T5 is connected to the contact point P5. Capacitors C15 and C16 which suppress voltage rise rates are connected in parallel to the trigger element, respectively. In addition, the gate of the trigger element is connected to the output terminal of the gate waveform shaping integrated circuit K02, and the other winding of the drive transformer T5 is connected to the input side of the gate waveform shaping integrated circuit K02. On the other hand, the contacts P3 of both smoothing elements of the rectifier 200 are simultaneously connected to the starter circuit portions C17, R6, and DIAC of the inverter portion. That is, the capacitor C17 of the starting circuit portion is connected to the terminals P6 and P4, the resistor R6 is connected between the terminals P3 and P4, and the diaak DIAC is connected to the gate of the terminal P4 and the trigger element Q2. Further, circuits R22 and D10 for stopping the operation of the starting circuit are connected between the terminals P4 and P5. The terminal P4 is connected to the next stage power control section (chip terminal 22 of the hybrid IC).

Since the operation of the input power supply unit 100 to the inverter unit 500 is not significantly different from that of the related art of FIG. 1, the description thereof is omitted.

The power controller 600 includes a regulator 610, a reference voltage generator 620, an input overvoltage detector 630, a temperature detector 640, a re-lighting time setter 650, a reference voltage setter 660, Pulse width adjusting section 670, hybrid IC 700 (K01) and other ancillary circuits.

In addition, as shown in FIG. 3, the hybrid IC includes an output detector 710, a multiplier 720, an ignition time controller 730, a drive transformer output adjuster 740, a temporary current detector 750, and other auxiliary devices. Circuits.

First, the other winding of the output transformer whose one winding is the output transformer T3 of the output matching section 4 is connected to chip terminals 13 and 14 of the IC. An output detector 710 including a bridge diode BD101 and a circuit D101, R101-R104, C101-C102, Q101 connected to the chip terminals 13 and 14 is connected to a voltage value. The output detector is connected to the multiplier 720 through the diode ZD101. The output side of the bridge diode BD101 is simultaneously connected to the current source A via a resistor R124. The other input of the multiplier is connected to chip terminal 5 through a resistor R1 for detecting an input current, and the other input is connected to chip terminal 6 through a connection point of resistors R7 and R8 for detecting an input voltage. do. The current input signals (output current, input current) are compared, input to one side input of the operational amplifier Q102 of the multiplier, and eventually multiplied by an input voltage value by the calculator. The other attraction force of the calculator Q102 comes from the chip terminal 7, and an adjustment value by the variable resistor VR1 and the resistors R17-R19 is applied to the chip terminal 7. The output of the calculator is fed back through a capacitor C105. R105-R107 is a resistor, and C103-C104 is a capacitor.

The output of the multiplier corresponds to the detected power value, which is in turn applied to one input side of the comparator Q103. The other input of the comparator Q103 becomes a reference voltage V1 applied through the chip terminal 11. The reference voltage V1 is applied to the chip terminal 11 through the constant voltage circuits C19, IC1, and R11. In addition, the phase correction circuits R12 and C24 connected to the chip terminal 9 are connected to the other input terminal of the comparator, and the other side of the phase correction circuit is connected to the upper potential terminal P1 of the rectifier 200.

The output of the comparator Q103 is connected to the chip terminal 20 through the inverter IN101, and the chip terminal 20 of the emitter ground switching element Q4 of the pulse width adjusting unit 670 is connected through the resistor R20. It is connected to the control terminal.

Meanwhile, another winding of the drive transformer T5 is connected to chip terminals 1 and 2 of the K01 IC 700, and a drive transformer output adjusting unit 740 is connected to the chip terminal. The output adjuster 740 rectifies the output of the drive transformer T5 input through the chip terminal first through the bridge diode BD102, and the rectified signal of the chip terminal 3 and the second switching element SCR. Is connected to the anode. The connection terminal of the charging capacitor C26 of the pulse width adjusting section 670 and the collector of the transistor Q4 as the switching element is connected to the outside of the IC of the third chip terminal through the zener diode ZD1.

On the other hand, the anode side of the thyristor, which is another output terminal of the drive transformer output adjusting unit 740, is simultaneously connected to the input terminal of the comparator Q104 through the resistor R122 and the diode D115. An IC driving voltage (+) is applied to the input terminal through the resistor R123. The other input of the comparator is a reference voltage (V1), the output is connected to the re-lighting time setting unit 650 through the chip terminal 10 through the resistor (R121) and the diode (D116), the re-lighting time It is connected to a capacitor C21 for setting the re-lighting delay time of the setting unit 650. A control diode ZD3 is connected to the capacitor C21.

The other input side of the comparator 104 is simultaneously connected to the collector side of the emitter ground switching transistor T102 of the temporary current detecting unit 750 and is connected to the current source A through the capacitor C108. The base side of the transistor is connected to the current source A and, at the same time, grounded through a resistor R120 and a capacitor C107.

The input terminal P3 is connected to the chip terminal 23 of the IC through the zener diode TVS and the resistor R14, and the chip terminal is simultaneously grounded through the charging capacitor C20. In addition, the IC inside the chip terminal 23 is connected to the gate of the thyristor SCR of the drive transformer output adjusting unit 740. In addition, the chip terminal 23 is connected to the base of the shutdown transistor T101 through the resistors R114 and R115, and the collector of the emitter ground shutdown transistor is a starter circuit of the inverter 500 as described above. C17).

The base side of the shutdown transistor is connected to the ignition time controller 720 at the same time, and the chip terminal 18, which is one side of the ignition time controller, is grounded through the capacitor C28 which sets the ignition allowable time again. The ignition time controller 720 includes a power supply (+), a plurality of diodes D108-D112, resistors R111-R113, and an inverter IN104-IN106.

The driving voltage Vcc of the IC is applied to the chip terminals 8 and 12 of the IC through the regulator 610, which simultaneously receives signals from the resistor R23 and the diode D15 from the chip terminal 3. . The IC inside the chip terminal 8 is connected to the thermistor TH through the parallel circuit of the resistor R109 and the diode D105 and the diode D106.

The operation of the electronic ballast of the first embodiment of the present invention will now be described.

First, when an input power source is applied to start a lamp, the DC voltage applied to the terminal P4 is charged through the resistor R6, and the first charging capacitor C17 is charged. The circuit is energized to turn on the MOSFET (Q2) which is a trigger element. Therefore, the resonant circuit of the output matching unit 400 starts to operate, which in turn detects a signal in the drive transformer T5. The drive transformer detects a signal and charges the second charging capacitor C26 of the pulse width adjusting unit 670 through the drive transformer output adjusting unit 740 of the IC 700. The charged voltage is charged / discharged by the on / off of the first switching element Q4. Thus, a pulse train having a pulse width corresponding to the on / off time is applied to the drive transformer T5. As a result, since the trigger circuits Q1 and Q2 are triggered, a plurality of pulse trains having a sufficient pulse width and amplitude are applied to the lamp output circuit, thereby successfully lighting the lamp. The pulse period depends on the parameter values of the resistor R6 and the capacitor C17 of the starting circuit, by the switching time of the first switching element Q4 of the pulse width and the amplitude to the second charging capacitor C26. Is determined by On the other hand, the control signal of the first switching element Q4 is, on the one hand, by the output current and input current sensing 710 and R1 of the output transformer T3 and the sensing of the input voltage R7 and R8 on the one hand. By comparing these current values with each other and multiplying the voltage values (720) to detect power, the signal is compared with the reference value (V1) by the comparator (Q103). In addition, since the comparator oscillates and becomes unstable when both signals have a phase difference of 180 ° or more, the comparator includes phase correction circuits R12 and C24 at one input terminal. In addition, the output terminal of the drive transformer T5 is held constant by the zener diode ZD1. Since the initial current is large at startup, the control signal is at the 'high' level. Therefore, the voltage of the third chip terminal is about 90V, for example, and the voltage of the second charging capacitor is about 80V. maintain. After the lamp is turned on, the control signal is at the 'middle' level, the voltage of the third chip terminal is, for example, about 39-40V and the terminal of the second charging capacitor C26 is maintained at about 15-20V. .

On the other hand, at startup, since the voltage of the input terminal P3 is in an overvoltage state, the third charging capacitor C20 of the input overvoltage detector 630 is also charged. Since the charged voltage triggers the gate of the second switching element thyristor SCR of the output adjuster 740, the pulse train of the drive transformer of the output adjuster 740 is more completely formed. Thereafter, the charging voltage of the third charging capacitor C20 is discharged by the resistors R114 and R115 and is not an overvoltage input after the lamp is turned on, so that the capacitor C20 is not charged and thus the input overvoltage detection unit 630. ) Stops the operation.

In addition, after starting, the output voltage of the drive transformer T5 becomes an input of the comparator Q104 to charge the fourth charging capacitor C21. While the fourth capacitor C21 is being charged, the drive The output of the transformer is provided so that it does not turn on again until the fourth capacitor C21 is discharged. Therefore, it is possible to prevent the starting operation that is unnecessary at the time of re-lighting or may damage the lamp. The parameter value of the fourth capacitor sets the re-lighting delay time of the lamp. In addition, in the case of starting up for a predetermined time but not turning on, after the predetermined time, the output of the ignition time control unit 730 turns on the fourth switching element T101 to thereby turn on the starting circuit unit C17. ) Will stop. The parameter value of the fifth charging capacitor C28 connected to the ignition time controller is used to set the predetermined time.

On the other hand, the driving voltage (+) of the IC chip is applied to the provisional current detection unit 750, if the output current flows, such as a starting voltage flows when the lamp is disabled in the output detection unit 710, it is detected by the home appliance Since the IC operating voltage is grounded by turning on the third switching element T102 of the flow detection unit 750, it is possible to block the flow of the temporary current harmful to the lamp or the circuit.

Finally, a thermistor TH is connected to the IC power supply terminal (No. 8 chip terminal). If the temperature rises and the resistance of the thermistor decreases, the power supply terminal becomes grounded. The power supply of the is cut off, which also protects the circuit. In some cases, the illumination measuring unit may be added to the chip terminals 15 and 16 to automatically start the ballast operation according to the external brightness.

Next, the electronic ballast according to the second embodiment of the present invention will be described with reference to FIG. For simplicity of explanation, the same elements as in the first embodiment are denoted by the same reference numerals, and detailed descriptions are omitted, and parts having similar functions are denoted by similar reference numerals.

As shown in Fig. 5, the electronic ballast according to the second embodiment of the present invention also employs the components of the first embodiment as it is, but the difference is that the trigger element Q1, The step-up transformer T6 is further employed between the contact point P5 of Q2) and the drive transformer T5. This makes it possible to make the lamp output even more perfect by increasing the output voltage of the lamp at startup.

In addition, a slight circuit correction has been made in the power control unit 600 '. In particular, in the case of the pulse width adjusting unit 670', the zener diode ZD1 is connected to the chip terminal 3 through the resistor R24, and again a diode It is connected to the charging capacitor C26 and the switching element Q4 via D14. In addition, the connection point of the zener diode ZD1 and the diode D14 is grounded through another zener diode ZD4 so as to maintain a constant voltage more reliably.

Although the present invention has been described above with reference to one embodiment shown in the accompanying drawings, the present invention is not limited thereto, and various modifications may be made within a range easily understood by those skilled in the art. Therefore, the limitation of the present invention should be limited only by the following claims.

As described above, according to the ballast according to the present invention, by applying a high-voltage pulse having a sufficient pulse width at the start of the lamp several times, it is possible to reliably turn on regardless of the type of the HID lamp, the constant power function of the output signal It further enhances the power supply, and provides immediate protection in case of lamp failure or surge voltage, and prevents unnecessary oscillation by correcting the phase of input current, and allows for delay time or re-attempt at re-lighting. It is possible to set the time.

Claims (8)

A rectifier 200 for rectifying an input AC signal to supply a DC voltage, a lamp matching part 400 for turning on a lamp by oscillating at a given resonance frequency by receiving a voltage applied from the rectifying part, and rectified from the rectifying part. In the electronic ballast for a high voltage discharge lamp comprising an inverter unit 500, 500 'that receives a voltage and causes resonance of the lamp matching unit, and a power control unit 600, 600' that controls the inverter unit. The lamp matching unit 400 includes resonant capacitors C12A, C12B, C13, and C14 and an inductor T4. The inverter units 500 and 500 ′ may be turned on / off by a drive transformer T5 having one winding electrically connected to the resonance inductor T4 and whether the other windings of the drive transformer are energized. Trigger elements Q1 and Q2 for triggering the resonant circuit of the lamp matching section to generate a high frequency output, start circuits C17, R6 and DIAC for operating any one of the trigger elements when the lamp is started and a lamp Circuits (R22, D10) for stopping the operation of the starting circuit after lighting, The power controllers 600 and 600 'compare output values T3 and 710 to detect an output signal to the lamp with a value detected by the output detector and an input current, and compare the compared value and input voltage. Multiplier 720 multiplying by a plurality of pulses having a predetermined pulse width through the drive transformer (T5) at the start-up of the lamp according to the comparison result of the power value and the reference value calculated by the multiplier Electronic ballast characterized in that it comprises a pulse width adjustment unit (670) to be applied to. The method of claim 1, The triggering circuit is initially charged by the supply voltage of the rectifying unit through a resistor R6 connected in series and the charged voltage of one of the trigger elements (Q1 or Q2) through the DIAC. It includes a first charging capacitor (C17) applied to the control terminal, The circuit for stopping the operation of the starting circuit includes a resistor (R22) for discharging the charging voltage of the capacitor (C17) after lighting. The method of claim 1, The pulse width adjusting unit 670 compares the power value of the second charging capacitor C26 and the multiplication circuit, which are charged by the effective value of the signal of another winding of the drive transformer T5, to the comparison result of the reference value. And a first switching element (Q4) for switching the charge / discharge of the second charging capacitor. The method of claim 3, wherein The pulse width adjusting unit 670 is supplied with a signal of another winding of the drive transformer T5 to the second charging capacitor C26 through the constant voltage diode ZD1, and is equal to the power value of the multiplication circuit. The switching device is turned on / off according to the comparison result of the reference value, the electronic ballast characterized in that to maintain the magnitude of the power of the signal flowing through the drive transformer (T5) to a constant size. The method of claim 1, The power control unit 600, 600 ′ further includes an input overvoltage detector 630 including a third charging capacitor C20 electrically coupled through an input terminal P3 and a constant voltage diode TVS. The transformer output adjusting unit 740 further includes a second switching element SCR connected to the output side of the drive transformer T5. The input overvoltage detector 630, At start-up, an input overvoltage is transmitted to the third charging capacitor through the constant voltage diode TVS to charge the third charging capacitor, and the voltage charged in the third charging capacitor is switched to the second switching capacitor. By turning on the device, the pulse width adjusting section can be operated more reliably, The electronic ballast is in an inoperative state after the lighting. The method of claim 1, The comparison between the power value of the multiplication circuit and the reference value is made by a comparator Q103 connected to the inverting stage input side of which the output of the multiplication circuit is connected to the non-inverting stage input side, and the circuit 660 for setting the reference value is connected to the inverting stage input side. The output of the comparison circuit 660 is made by the phase correction circuit (R12, C24) connected to the power input terminal (P1) again. The method of claim 1, The power control unit further includes a temporary current detector 750 connected to the output current detector 710, The temporary current detector 750 may turn off the supply of the IC operating power by turning on the third switching element T102 when the temporary current is detected when the lamp is disabled, thereby stopping the operation of the power controller. ballast. The method of claim 1, The power control unit further includes a re-lighting time setting unit 650 including fourth and fifth charging capacitors C21 and C28. The fourth charging capacitor C21 is connected to an output terminal of the drive transformer output adjusting unit 740, and is charged when the lamp is 'on' and discharged when the lamp is 'off', and during charging, By maintaining the output at a constant voltage to prevent the pulse from being applied to the resonant circuit, the re-lighting delay time is set, The starter circuits C17, R6, and DIAC are grounded through the fourth switching element T101, and the control terminal of the fourth switching element sets the ignition time upon re-lighting through the ignition time controller 730. The electronic ballast, which is connected to a fifth charging capacitor (C28), stops the operation of the starting circuit if the lighting is not successful within a predetermined time.