KR100726474B1 - Electronic ballast for lighting high voltage discharge lamp - Google Patents

Abstract

An electronic ballast for lighting a high voltage discharging lamp is provided to prevent the damage by stopping an operation of a lamp driving controlling unit by absorbing an overcurrent or overvoltage in a ballast protecting unit. An electronic ballast for lighting a high voltage discharging lamp(105) includes a voltage converting unit(111), a lamp driving unit(151), a lamp driving controlling unit(141), a ballast protecting unit(161), and a re-lighting protecting unit(171). The voltage converting unit(111) converts AC voltage, applied from the outside, to DC voltage. The lamp driving unit(151) drives the high voltage discharging lamp(105). The lamp driving controlling unit(141) is connected with the lamp driving unit(151) and the voltage converting unit(111), and controls operation of the lamp driving unit(151) by receiving the DC voltage. The ballast protecting unit(161) is connected with the lamp driving controlling unit(141) and the lamp driving unit(151), and protects the electronic ballast by blocking an output of the lamp driving controlling unit(141) if over-current flows in the lamp driving unit(151) or over-voltage is applied. The re-lighting protecting unit(171) is connected with an input stage of the lamp driving controlling unit(141) and an input stage of the voltage converting unit(111), and stops operation of the lamp driving controlling unit(141) until first lighting of the high voltage discharging lamp(105) fails and the lamp(105) is re-lighted. The re-lighting protecting unit(171) includes a thermistor connected to the input stage of the voltage converting unit(111), and a temperature switch connected to the input stage of the lamp driving controlling unit(141) and turned on if the temperature of the thermistor is over predetermined temperature and turned off if the temperature of the thermistor is below the predetermined temperature.

Description

Electronic ballast for lighting high voltage discharge lamp {Electronic ballast for lighting high voltage discharge lamp}

BRIEF DESCRIPTION OF THE DRAWINGS In order to better understand the drawings cited in the detailed description of the invention, a brief description of each drawing is provided.

1 is a block diagram of an electronic ballast of the present invention connected to a high pressure discharge lamp.

FIG. 2 is a circuit diagram of the electronic ballast shown in FIG. 1.

FIG. 3 shows another embodiment of the first switching device shown in FIG. 2.

4 shows another embodiment of the first switching device shown in FIG. 2.

FIG. 5 illustrates a structure of the first to third inductors shown in FIG. 2.

The present invention relates to an electronic ballast for lighting a high-pressure discharge lamp, and more particularly to an electronic ballast for preventing damage to the internal electrical elements when an abnormality occurs in the process of lighting the high-pressure discharge lamp.

The high-pressure discharge lamp has gas injected therein and emits light when the gas is excited. In general, the high voltage discharge lamp operates at a high voltage because high voltage is required to excite the gas, and thus the power consumption is very large, reaching 100 [W] to 1000 [W]. The high-pressure discharge lamp is classified into a sodium lamp, a metal halide lamp, and an electrodeless lamp according to the type of gas injected therein.

Since the high-pressure discharge lamp has a higher power efficiency than a general bulb, it is widely used for outdoor lighting, such as a large building such as a department store or a gymnasium, or a street lamp in a park or a street.

However, since the protection circuit is not provided separately in the conventional ballast, when the output terminal of the ballast to which the high-pressure discharge lamp is connected is short-circuited or an input voltage is applied to the output terminal of the ballast, the high-pressure discharge lamp is not properly turned on. In the case of re-lighting, a large amount of current flows to the ballast, which may damage the electric elements inside the ballast.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic ballast for lighting a high pressure discharge lamp which prevents damage in the case of an output short circuit to which the high pressure discharge lamp is connected.

Another object of the present invention is to provide an electronic ballast for lighting a high-pressure discharge lamp that prevents damage when an input voltage is applied to an output terminal instead of an input terminal.

Still another object of the present invention is to provide an electronic ballast for lighting a high-pressure discharge lamp that prevents damage due to overvoltage in the process of initial lighting of the high-pressure discharge lamp fails to re-light.

The present invention to achieve the above technical problem

An electronic ballast for lighting a high-pressure discharge lamp, comprising: a voltage converter configured to convert an AC voltage into a DC voltage; A lamp driver driving the high pressure discharge lamp; A lamp driving controller connected to the voltage converter and the lamp driver and controlling the operation of the lamp driver by receiving the DC voltage; A ballast protection unit which is connected to the lamp driving unit and the lamp driving control unit and protects the ballast by blocking an output of the lamp driving control unit when an overcurrent flows or an overvoltage is applied to the lamp driving unit, and an input terminal of the voltage conversion unit; A re-lighting protection part connected to an input terminal of the lamp driving control part and stopping the operation of the lamp driving control part until the initial lighting of the high-pressure discharge lamp fails after being re-lit, and the re-lighting protection part converts the voltage A thermistor connected to a negative input terminal, and connected to an input terminal of the lamp driving control unit and bonded to an outer side of the thermistor, the temperature switch being turned off when the temperature of the thermistor is higher than a set temperature and turned on when the temperature of the thermistor is lower than a set temperature. High pressure discharge lamp lighting electronic having Provide a ballast.

Preferably, the constant voltage unit is further provided between the voltage conversion unit and the lamp driving control unit, and the constant voltage unit makes the DC voltage output from the voltage conversion unit to a constant voltage level and applies it to the lamp driving control unit. The apparatus may further include a current limiting unit connected between the constant voltage unit and the lamp driving control unit, wherein the current limiting unit blocks an overcurrent from being input to the lamp driving control unit.

The lamp driving controller includes a trigger signal generator and first and second pulse signal generators, and the trigger signal generator generates a trigger signal by receiving a DC voltage output from the voltage converter. The pulse signal generator receives a first field effect transistor connected to the lamp driver and generates a pulse signal, a first inductor connected to the lamp driver, and an output signal of the trigger signal or the first inductor to receive a waveform thereof. A first waveform shaping unit configured to turn on the first field effect transistor by shaping the second field effect transistor, wherein the second pulse signal generator is connected to the lamp driver and generates a pulse signal, and a second field effect transistor connected to the lamp driver; A second field effect transistor by shaping a waveform of a second inductor and an output signal of the second inductor; And a second waveform shaping unit for turning on the stuffer.

Preferably, the lamp driving unit includes an output transformer, and the ballast protection unit includes first and second switching elements connected to the secondary side of the output transformer and the lamp driving control unit, and to the primary side of the output transformer. When an overvoltage or an overcurrent flows, the first and second switching elements are turned on by a voltage induced on the secondary side of the output transformer so that an internal current of the lamp driving control unit may cause the first and second switching elements to operate. By flowing through, no output signal is generated from the lamp driving controller.

According to the present invention, the ballast is not damaged even if an abnormality occurs.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals in the drawings denote like elements.

1 is a block diagram of an electronic ballast of the present invention connected to a high pressure discharge lamp. Referring to FIG. 1, the electronic ballast 101 includes a voltage converting unit 111, a constant voltage unit 121, a current limiting unit 131, a lamp driving control unit 141, a lamp driving unit 151, and a ballast protecting unit 161. ) And a re-lighting protection unit 171.

The high pressure discharge lamp 105 is connected to an output terminal (p1, p2 of FIG. 2) of the lamp driver 151. The high voltage discharge lamp 105 is operated by a high voltage and includes an electrodeless lamp and a high intensity discharge (HID) lamp.

The voltage converter 111 converts the commercial AC voltage VAC into a DC voltage. The commercial AC voltage VAC, such as 110 volts or 220 volts, is applied to the voltage converter 111, and the voltage converter 111 converts the input commercial AC voltage VAC into a DC voltage and outputs the DC voltage.

The constant voltage unit 121 is connected between the voltage converter 111 and the current limiter 131. The constant voltage unit 121 makes the DC voltage output from the voltage converter 111 at a constant voltage level and applies it to the current limiting unit 131. Therefore, a constant DC voltage is always input to the current limiting unit 131 by the constant voltage unit 121.

The current limiting unit 131 is connected between the constant voltage unit 121 and the lamp driving control unit 141 and suppresses the overcurrent from being input to the lamp driving control unit 141. A constant voltage is always input to the lamp driving controller 141 by the constant voltage unit 121, but an overcurrent may be input due to external noise or an unstable operation of the ballast 101 itself. The current limiter 131 blocks such external noise or overcurrent from being input to the lamp driving controller 141.

The lamp driving control unit 141 receives the DC voltage input through the current limiting unit 131 and controls the operation of the lamp driving unit 151. That is, the lamp driving controller 141 generates a continuous pulse signal and provides the generated pulse signal to the lamp driver 151 to cause the lamp driver 151 to emit the high pressure discharge lamp 105.

The lamp driver 151 is connected to the lamp driving controller 141 and the high pressure discharge lamp 105, and receives the output of the lamp driving controller 141 to emit the high pressure discharge lamp 105.

The ballast protector 161 is connected to the lamp driver 151 and the lamp driving controller 141. The ballast protector 161 protects the ballast 101 by blocking an output of the lamp driving controller 141 when an overcurrent flows or an overvoltage is applied to the lamp driver 151. That is, when the output terminal of the ballast 101 to which the high-pressure discharge lamp 105 is connected is shorted, overcurrent flows to the ballast 101, and a commercial AC voltage to be applied to the input terminal of the AC-DC converter by a user's mistake. When VAC is input to the output terminal (p1, p2 of FIG. 2) of the ballast 101, an overvoltage is applied to the output terminal (p1, p2 of FIG. 2) of the ballast 101. In addition, a time delay may be added to unnecessary power consumption due to the continuous operation of the trigger signal generator (211 of FIG. 2) provided in the lamp driving controller 141 during the re-lighting period due to the failure of lamp lighting. do. The ballast protection unit 161 prevents the ballast 101 from being damaged by the overcurrent or the overvoltage as described above, and also prevents unnecessary power consumption due to the re-lighting circuit operation.

The re-lighting protection unit 171 protects the electronic ballast 101 by stopping the operation of the electronic ballast 101 until the high-pressure discharge lamp 105 is re-lit after the initial lighting of the high-pressure discharge lamp 105 has failed. do. That is, when the initial lighting of the high-pressure discharge lamp 105 fails, the high-pressure discharge lamp 105 must be re-lit after the high-pressure discharge lamp 105 is cooled. As such, the operation of the electronic ballast 101 should be stopped while the high-pressure discharge lamp 105 is cooled. At this time, if the electronic ballast 101 is operated, unnecessary power is consumed, and the electronic ballast 101 The internal components of the circuit are likely to be damaged. Therefore, when the initial lighting of the high-pressure discharge lamp 105 fails, the re-lighting protection unit 171 stops the operation of the electronic ballast 101, and restarts the re-lighting in a state where the high-pressure discharge lamp 105 is sufficiently cooled. By doing so, it is possible to prevent damage to the internal elements of the electronic ballast 101 and also to prevent unnecessary power consumption.

FIG. 2 is a circuit diagram of the electronic ballast shown in FIG. 1.

2, the current limiting unit 131 includes a plurality of diodes D1 to D4. The diodes D1 to D4 are turned on when the built-in voltage is higher than the built-in voltage, respectively.

Referring to FIG. 2, the lamp driving controller 141 includes a re-lighting controller 215, a trigger signal generator 211, a first pulse signal generator L1, 221, 241, and a second pulse signal generator L2, 231, 242. ), Resistors R3 and R4 and capacitors C3 and C4.

The trigger signal generator 211 receives a DC voltage output from the current limiter 131 and generates a trigger signal. The first field effect transistor 241 is turned on by the trigger signal generated from the trigger signal generator 211, so that the voltage input to the lamp driver 151 is supplied to the high voltage discharge lamp 105. It is applied and the high pressure discharge lamp 105 emits light. In this regard, the trigger signal generator 211 serves as an ignitor. The trigger signal generator 211 includes resistors R1 and R2, a capacitor C1, and a die solution DA1.

The first pulse signal generators L1, 221, and 241 may include a first field effect transistor 241 connected to the lamp driver 151, a first inductor L1 connected to the lamp driver 151, and a first waveform shaping unit 221. ).

The first field effect transistor 241 is of N-channel type and is turned on when a threshold voltage or more is applied to the gate. The first field effect transistor 241 generates a pulse signal.

As shown in FIG. 5, the first inductor L1 forms a magnetic coupling with the third inductor L3 provided in the lamp driver 151. That is, the third inductor L3 forms a primary side winding, and the first inductor L1 forms a secondary side winding. Therefore, when a current flows in the third inductor L3, a voltage is induced in the first inductor L1 to generate counter electromotive force.

The first waveform shaping unit 221 receives a trigger signal generated from the trigger signal generating unit 211 or an output signal of the first inductor L1 and shapes these waveforms to form gates of the first field effect transistor 241. Is authorized. That is, the trigger signal output from the trigger signal generator 211 or the output signal of the first inductor L1 may include noise, and the first waveform shaping unit 221 removes such noise to shape the signal. The first field effect transistor 241 can operate stably. The first waveform shaping unit 221 includes a capacitor C2, resistors R5 to R8, and zener diodes Z1 to Z6. The capacitor C2 removes noise by bypassing an AC component, and the resistors R5 to R8 and the zener diodes Z1 to Z6 form a stepwise signal.

The second pulse signal generators L2, 231 and 242 may include a second field effect transistor 242 connected to the lamp driver 151, a second inductor L2 connected to the lamp driver 151, and a second waveform shaping unit 231. ).

The second field effect transistor 242 is of N-channel type, and is turned on when a threshold voltage or more is applied to the gate. The pulse signal is generated from the second field effect transistor 242.

As shown in FIG. 5, the second inductor L2 forms a magnetic coupling with the third inductor L3 provided in the lamp driver 151. That is, the third inductor L3 forms the primary side winding, and the second inductor L2 forms the secondary side winding. Therefore, when a current flows in the third inductor L3, a voltage is induced in the second inductor L2 to generate counter electromotive force.

The second waveform shaping unit 231 receives the output signal of the second inductor L2, shapes the waveform, and applies the waveform to the gate of the second field effect transistor 242. That is, the output signal of the second inductor L2 may include noise, and the second field effect transistor 242 may operate stably by removing the noise and shaping the signal. The second waveform shaping unit 231 includes a capacitor C5, resistors R10 to R13, and zener diodes Z7 to Z12. The capacitor C5 removes noise by bypassing the AC component, and the resistors R10 to R13 and the zener diodes Z7 to Z12 shape the input signal in stages.

Referring to FIG. 2, the lamp driver 151 includes capacitors C6 to C9 and C13, resistors R20 and R21, diodes D4 and D5, a third inductor L3, and an output transformer 271. And a high-pressure discharge lamp 105 is driven. Capacitors C6, C7 and C13 and resistors R20 and R21 soft start a high-pressure discharge lamp connected to output pins P1 and P2.

Referring to FIG. 2, the ballast protection unit 161 is connected to the secondary winding of the output transformer 271, and when a current flows in the primary side of the output transformer 271, the voltage is induced to operate. The ballast protection unit 161 includes a light emitting diode 261, resistors R14 to R19, diodes D7 to D9, capacitors C11 and C12, a first switching element 251, and a second switching element ( 252 and the voltage limiter 281.

The light emitting diode 261 emits light when the ballast protection unit 161 operates.

The first switching element 251 includes a silicon controlled rectifier (SCR). The anode of SCR 251 is connected to diode D9, the gate of SCR 251 is connected to resistor R18, and the cathode of SCR 251 is node N1. ) The SCR 251 is activated when the current applied to the gate exceeds a predetermined level. When the first switching device 251 is activated, the internal current of the trigger signal generator 211 flows to the node N1 through the SCR 251, and thus a trigger signal is output from the trigger signal generator 211. Will not be. If the trigger signal is not output, the first field effect transistor 241 does not perform a switching operation. The ballast protection unit 161 operates when an overcurrent or overvoltage is applied to the inside of the ballast (105 of FIG. 1), and thus damages to the ballast (101 of FIG. 1) as the first switching element 251 is activated. This is avoided.

The second switching element 252 includes an NPN transistor. The NPN transistor 252 is turned on when a threshold voltage or more is applied to the gate. When the second switching element 252 is activated, since the internal current of the first waveform shaping unit 221 flows through the second switching element 252, the output signal is not output from the first waveform shaping unit 221. Therefore, the first field effect transistor 241 is turned off. Therefore, the operation of the ballast (101 in FIG. 1) is stopped to prevent damage to the ballast (101 in FIG. 1).

The voltage limiter 281 is connected between the resistor R16 and the resistor R18 and limits the voltage so that an overvoltage is not applied to the gate electrode of the SCR 251. The voltage limiter 281 includes a zener diode 283 and a general diode 285. The zener diode 283 outputs only a predetermined voltage when a predetermined voltage or more is input. When an overvoltage is applied to the gate electrode of the SCR 251, the SCR 251 is damaged to prevent normal operation. The voltage limiting unit 281 is provided to prevent the SCR 251 from being damaged. The voltage limiter 281 always applies only a constant voltage or less to the gate of the SCR 251. Therefore, the overvoltage is not applied to the gate of the SCR 251, so that the SCR 251 is not damaged.

Referring to FIG. 2, the re-lighting protection unit 171 includes a thermistor 171a and a temperature switch 171b.

The thermistor 171a has a characteristic that the internal resistance decreases as the temperature increases. That is, when the amount of current flowing inside increases, the temperature of the thermistor 171a becomes high. Therefore, by measuring the temperature of the thermistor 171a, the amount of the electric current which flows through the electronic ballast 101 can be known. In addition, the thermistor 171a serves to reduce inrush current generated in the electronic ballast 101. That is, although the resistance value of the thermistor 171a is large at the initial stage when the commercial AC voltage VAC is applied, heat is generated in the thermistor 171a as time passes, so that the resistance value of the thermistor 171a is reduced. . By using such a heat characteristic, inrush current generation can be suppressed by limiting the current supply to the circuit at the time of initial lighting of the electronic ballast 101.

The temperature switch 171b performs a switching role according to the height of the temperature of sensing the external device. For example, the temperature switch 171b is turned off when the sensed temperature is higher than the set temperature of the temperature switch 171b, and is turned on when the sensed temperature is lower than the set temperature of the temperature switch 171b. The temperature switch 171b is connected to the input terminal of the lamp driving controller 141. The temperature switch 171b is also adhered to one surface of the thermistor 171a. Accordingly, the temperature switch 171b senses the temperature of the thermistor 171a to control the operation of the lamp driving controller 141. That is, when the temperature of the thermistor 171a becomes higher than the set temperature of the temperature switch 171b, the temperature switch 171b is turned off to stop the operation of the lamp driving control unit 141, and the temperature of the thermistor 171a is set to the temperature switch ( When the temperature is lower than the set temperature of 171b, the temperature switch 171b is turned on to activate the operation of the lamp driving controller 141.

Specifically, when the high-pressure discharge lamp (105 in FIG. 1) is normally turned on, since the current flows continuously in the thermistor 171a, the temperature switch 171b is turned off, and thus the lamp driving controller 141 is shut off to operate. Stop. At this time, when the initial lighting of the high-pressure discharge lamp (105 in FIG. 1) fails to turn on again, current flows through the thermistor 171a during the initial lighting, and heat is generated, but the thermistor 171a is caused by a decrease in the current caused by the failure of the lighting. Temperature drops). Then, when the temperature of the thermistor 171a falls below the set temperature of the temperature switch 171b, the temperature switch 171b is turned on again, and the lamp drive control unit 141 operates again to thereby operate the high pressure discharge lamp (105 in FIG. 1). ) Lights up.

1 and 2, the overall operation of the ballast 101 will be described.

When the commercial AC voltage VAC input to the voltage converter 111 from the outside is converted into a DC voltage and outputted, the capacitor C1 of the trigger signal generator 211 is charged by the DC voltage. When the capacitor C1 is fully charged, the die solution DA1 is turned on to generate a trigger signal. The trigger signal is shaped by the first waveform shaping unit 221 and applied to the gate of the first field effect transistor 241 to turn on the first field effect transistor 241. When the first field effect transistor 241 is turned on, the capacitor C8, the capacitor C7, the capacitor C6, the output transformer 271, and the third inductor L3 are driven by the voltage output from the voltage converter 111. L3 and a driving current flow through the first field effect transistor 241. When the capacitor C8 is fully charged, the driving current does not flow, and at the same time, the first field effect transistor 241 is turned off.

Subsequently, a counter electromotive force is generated from the second inductor L2, which is shaped by the second waveform shaping unit 231 and applied to the gate of the second field effect transistor 242, thereby corresponding to the second field effect transistor 242. ) Is turned on. When the second field effect transistor 242 is turned on, the second field effect transistor 242, the third inductor L3, the output transformer 271, and the capacitor C6 are driven by the voltage output from the voltage converter 111. The driving current flows through the capacitor C7 and the capacitor C10. When the capacitor C10 is fully charged, the driving current does not flow, and at the same time, the second field effect transistor 242 is turned off.

Subsequently, a counter electromotive force is generated from the first inductor L1, which is shaped by the first waveform shaping unit 221 and applied to the gate of the first field effect transistor 241, thus corresponding to the first field effect transistor 241. ) Is turned on. When the first field effect transistor 241 is turned on, the capacitor C8, the capacitor C7, the capacitor C6, the output transformer 271, and the third inductor L3 are driven by the voltage output from the voltage converter 111. ), The driving current flows again through the first field effect transistor 241. When the capacitor C8 is fully charged, the driving current does not flow, and at the same time, the first field effect transistor 241 is turned off.

As such, the pulse signal generated from the lamp driving controller 141 by the alternating and repetitive on / off operation of the first field effect transistor 241 and the second field effect transistor 242 is output to the output transformer 271. High voltage discharge connected to the output terminals p1 and p2 while a high voltage, for example, 3 to 5 [kV] is generated at the output terminals p1 and p2 at the moment when the resonant frequency occurs while passing through the primary winding and the capacitors C6 and C7. The lamp 105 is turned on.

On the other hand, the high-pressure discharge lamp 105 may fail momentarily or completely fail. The failure of the high-pressure discharge lamp 105 completely includes a case in which the output terminals p1 and p2 are short-circuited or a voltage to be input to the voltage converter 111 is applied to the output terminals p1 and p2. When the high-pressure discharge lamp 105 is a momentary power outage, it takes about 2 to 5 minutes until sufficient cooling occurs. However, the lamp driving control unit 141 does not recognize when the high-pressure discharge lamp 105 is a momentary power failure or a complete failure, and generates a high-voltage pulse for continuous lighting. As such, the high voltage for lighting generated from the output transformer 271 is not applied to the high-pressure discharge lamp 105 during the continuous operation of the lamp driving control unit 141, and thus a high voltage is applied to the secondary side of the output transformer 271. This is organic. At this time, the overvoltage detected through the secondary winding of the output transformer 271 is reduced through the resistor R15, and after being rectified through the diode D7, is charged in the capacitor C11. Therefore, the timing of turning on the high-pressure discharge lamp 105 is adjusted by the time constants of the capacitor C11 and the resistor R17.

When charging of the capacitor C11 is completed, the first switching element 251 is turned on, and the first switching element 251 is in accordance with the state of charge of the capacitor C11 and the value of the resistor R17 for adjusting the lighting timing. On and off is repeated, the state of charge for the capacitor (C1) is adjusted according to the repeated on and off for adjusting the lighting timing of the first switching element 251, the die solution (DA1) Is turned on and off to adjust the switching timing of the turn-on and turn-off of the first and second field effect transistors 241 and 242 of the lamp driving controller 141.

On the other hand, the overvoltage induced by the secondary winding of the output transformer 271 is down by the resistor R14 and rectified through the diode D6, the voltage corresponding to the on condition of the die liquid DA2, for example, In the case of exceeding the setting value of 34 [V], the die solution DA2 is turned on, and the second switching element 252 is turned on accordingly.

As the second switching element 252 is turned on, while the counter electromotive force of the first inductor L1 is bypassed, the repetitive turn-on and turn-off operations of the first and second field effect transistors 241 and 242 are stopped, thereby driving the lamp driver 151. The supply of the drive current is completely cut off due to the oscillation of the resonance frequency. That is, the ballast protection unit 161 continuously operates the lamp driving control unit 141 when the lighting fails due to the failure of the high-pressure discharge lamp 105 or the time taken until the high-pressure discharge lamp 105 is sufficiently cooled. When detecting the high voltage for lighting generated by the operation, the switching operation of the first and second field effect transistors (241, 242) is stopped to prevent the high voltage for lighting from being input to the lamp driver 151, thereby providing It is possible to prevent damage and shorten the life of circuit elements included in the lamp driving control unit 141 including the field effect transistors 241 and 242, and to reduce power consumption by suppressing continuous high voltage for lighting.

3 shows another embodiment of the first switching element 251 shown in FIG. 2. Referring to FIG. 3, the first switching element 251 includes a diode 311 and an NPN transistor 321. The collector C of the NPN transistor 321 is connected to a diode (D9 of FIG. 2), the base B of the NPN transistor 321 is connected to a resistor (R18 of FIG. 2), and the Emitter E is connected to node N1. The NPN transistor 321 is turned on when the voltage applied to the base B becomes higher than or equal to the threshold voltage of the NPN transistor 321. When the NPN transistor 321 is turned on, the internal current of the trigger signal generator 211 flows to the node N1 through the NPN transistor 321, so that the trigger signal is not output from the trigger signal generator 211. Do not. If the trigger signal is not output, the first field effect transistor 251 of FIG. 2 does not perform a switching operation, and as a result, the operation of the ballast 101 (FIG. 1) is stopped to prevent damage to the ballast 101 (FIG. 1). do.

4 shows another embodiment of the first switching element 251 shown in FIG. 2. Referring to FIG. 4, the first switching element 251 includes a triac 421 and a diode 411. The first anode A1 of the triac 421 is connected to a diode (D9 of FIG. 2), the gate G of the triac 421 is connected to a resistor (R18 of FIG. 2), and the triac 421 The second anode A2 of) is connected to node N1. The triac 421 is activated when the voltage applied to the gate G reaches a predetermined level. When the triac 421 is activated, an internal current of the trigger signal generator 211 flows to the node N1 through the triac 421, and thus a trigger signal is not output from the trigger signal generator 211. Do not. If the trigger signal is not output, the first field effect transistor 241 does not perform a switching operation. As a result, the operation of the ballast 101 (FIG. 1) is stopped to prevent damage to the ballast 101 (FIG. 1).

FIG. 5 illustrates a structure of the first to third inductors shown in FIG. 2. Referring to FIG. 5, the first to third inductors L1 to L3 are composed of a transformer 511, and the third inductor L3 forms a primary winding of the transformer 511. The first and second inductors L1 and L2 form a secondary winding of the transformer 511. Therefore, when a voltage is applied to the third inductor L3, the voltage is induced to the first and second inductors L1 and L2. The magnitude of the voltage induced in the first and second inductors L1 and L2 is determined by the winding ratio of the primary side to the secondary side of the transformer 511.

Optimum embodiments have been disclosed in the drawings and specification, and those skilled in the art will appreciate that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit described in the appended claims.

As described above, the electronic ballast 101 of the present invention includes the ballast protection unit 161, so that when an abnormality occurs in the ballast 101, for example, the high-pressure discharge lamp 105 may fail momentarily or the output stage p1. When the p2 is shorted or a voltage to be input to the voltage converting unit 111 is applied to the output terminals p1 and p2, the ballast protection unit 161 operates to absorb the overcurrent or overvoltage flowing inside the ballast, thereby driving the lamp control unit. By stopping the operation of 141, damage to the ballast 101 is prevented.

In addition, by providing the re-lighting protection unit 171, when the initial lighting of the high-pressure discharge lamp 105 fails and re-lights, damage to the electronic ballast 101 is prevented, and unnecessary power consumption is prevented.

Claims (10)

In an electronic ballast for lighting a high-pressure discharge lamp, A voltage converter converting a commercial AC voltage input from the outside into a DC voltage; A lamp driver driving the high pressure discharge lamp; A lamp driving controller connected to the voltage converter and the lamp driver and controlling the operation of the lamp driver by receiving the DC voltage; A ballast protection unit connected to the lamp driving unit and the lamp driving control unit and blocking the output of the lamp driving control unit when an overcurrent flows or an overvoltage is applied to the lamp driving unit to protect the electronic ballast; And A re-lighting protection unit connected to an input terminal of the voltage conversion unit and an input terminal of the lamp driving control unit, and configured to stop the operation of the lamp driving control unit until the initial lighting of the high-pressure discharge lamp fails and then restarts; The re-lighting protection unit is connected to an input terminal of the voltage converting unit and an input terminal of the lamp driving control unit and is bonded to the outside of the thermistor, and is turned off when the temperature of the thermistor becomes higher than the set temperature, and the temperature of the thermistor is set temperature. An electronic ballast for lighting a high-pressure discharge lamp, comprising: a temperature switch that is turned on when lower. The method of claim 1, further comprising a constant voltage unit connected between the voltage converter and the lamp driving controller, wherein the constant voltage unit is configured to apply a DC voltage output from the voltage converter to a constant voltage level to the lamp driving controller. Electronic ballast for lighting high-pressure discharge lamp, characterized in that. 3. The method of claim 2, further comprising a current limiting unit connected between the constant voltage unit and the lamp driving control unit, wherein the current limiting unit blocks an overcurrent from being input to the lamp driving control unit. Electronic safety device. The method of claim 1, wherein the lamp driving control unit A trigger signal generator for receiving a DC voltage output from the voltage converter and generating a trigger signal; A first field effect transistor connected to the lamp driver and generating a pulse signal, a first inductor connected to the lamp driver, and receiving an output signal of the trigger signal or the first inductor and shaping their waveforms to form the first electric field A first pulse signal generator having a first waveform shaping unit for turning on the effect transistor; And A second field effect transistor connected to the lamp driver to generate a pulse signal, a second inductor connected to the lamp driver, and a second waveform to turn on the second field effect transistor by shaping a waveform of an output signal of the second inductor An electronic ballast for lighting a high-pressure discharge lamp, comprising: a second pulse signal generator having a waveform shaping unit. The lamp driver of claim 1, wherein the lamp driver includes an output transformer, and the ballast protection unit includes first and second switching elements connected to a secondary side of the output transformer and the lamp driving controller, and the primary side of the output transformer. When overvoltage or overcurrent flows, the first and second switching elements are turned on by the voltage induced on the secondary side of the output transformer so that the internal current of the lamp driving controller is controlled by the first and second switching devices. The electronic ballast for lighting a high-pressure discharge lamp, characterized in that the output signal is not generated from the lamp drive control unit by flowing through the elements. 6. The electronic ballast of claim 5, wherein the first switching element comprises an SCR. 6. The electronic ballast of claim 5, wherein the first switching element comprises an NPN transistor and a diode connected to an emitter of the NPN transistor. 6. The electronic ballast of claim 5, wherein the first switching element includes a triac and a diode connected to a second anode of the triac. delete delete

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