KR100452341B1 - Short protection circuit for magnetic-type ballast of high intensity discharge lamp - Google Patents

Abstract

The present invention relates to a short circuit protection circuit of a magnetic ballast for a high-pressure discharge lamp. Basically, the present invention is basically added to the magnetic ballast for high-pressure discharge lamp to sense the short circuit state from the voltage across the output of the ballast to interrupt the AC input power input to the ballast. Therefore, in the present invention, the input interrupter and the short circuit detection unit are further included in the conventional ballast for a high-pressure discharge lamp. The short circuit detection unit includes a capacitor charging and discharging depending on whether the output ends of the ballasts are short-circuited, and a transistor turned on / off according to the charging / discharging state of the capacitor. The input disconnection unit is a photocoupler that receives an output signal of the short circuit detection unit. And a relay to control the input power.

Description

Short protection circuit for magnetic-type ballast of high intensity discharge lamp

The present invention relates to a ballast circuit for a high-pressure discharge lamp. More specifically, the present invention relates to a short circuit protection circuit of a magnetic ballast for a high voltage discharge lamp, which is added to a conventional magnetic ballast for a high voltage discharge lamp and detects a short circuit condition from an output voltage across the ballast to interrupt the input power. will be.

In order to turn on the high-pressure discharge lamp (mercury lamp, sodium lamp, metal halide lamp, etc.) which are widely used for street light lighting and high ceiling lighting, a ballast is required to supply high initial starting voltage to the lamp and to control the current after the lighting. Do.

Generally, ballasts include electronic ballasts and magnetic ballasts. In electronic ballasts, if the output ends are short-circuited due to incorrect wiring, defective sockets, or lamp breakage, it is possible to shut off the input power by detecting a short-circuit condition. However, such a short circuit protection circuit exists in magnetic ballasts. I never do that.

When both ends of the output are short-circuited by the above reasons, the lamp is not turned on and consumes the active power and the large apparent power.

The present invention has been made to solve the problems of the conventional magnetic ballast for high-pressure discharge lamp as described above, the object of the present invention is the magnetic wire ballast for the high-pressure discharge lamp, both ends of the output line of the output line, defective socket or broken lamp In the case of a short circuit, the short circuit detection unit detects a voltage and cuts off the power at the input intermittent unit, thereby providing a short circuit protection circuit to prevent unnecessary power consumption.

1 is a block diagram of a circuit according to the present invention;

2 is an embodiment of a circuit according to the present invention;

<Description of Drawing>

Power input section 21, ballast 22, igniter 23, lamp 24, short circuit detection section 25, input intermittent 26

<Overview of invention>

Basically, the present invention is basically added to the magnetic ballast for high-pressure discharge lamp to sense the short circuit state from the voltage across the output of the ballast to interrupt the AC input power input to the ballast.

Therefore, in the present invention, the input interrupter and the short circuit detection unit are further included in the conventional ballast for a high-pressure discharge lamp. The short circuit detection unit includes a capacitor charging and discharging depending on whether the output ends of the ballasts are short-circuited and a transistor turned on / off according to the charge / discharge state of the condenser, and the input disconnection unit receives an output signal of the short circuit detection unit. It includes a photocoupler and a relay to control the input power.

Hereinafter, specific embodiments will be described with reference to the drawings.

Specific Example

1 is a block diagram showing the basic configuration of the present invention, Figure 2 is a detailed circuit diagram of one embodiment.

Referring to Figure 1, the present invention is approximately,

A power input unit 21 into which AC power is input;

Known magnetic ballast 22 including an igniter 23 for lighting a lamp 24 by outputting a high voltage pulse voltage from the voltage input to the power input unit 21,

Short-circuit detection unit 25 for detecting when the output both ends of the ballast 22 is short-circuited due to a wrong wiring of the output line or a failure of the socket or breakage of the lamp,

According to the detection signal of the short circuit detection unit 25, when detected in a short circuit state, the power input to the power input unit 21 is cut off, and when it is detected that the short circuit state is connected to the input interruption It consists of a part 26.

Next, with reference to FIG. 2, the specific structure and operation | movement of each block of FIG. 1 are demonstrated.

-Igniter (23)

As shown in FIG. 2, the igniter 23 includes a tap transformer T1 having one end connected to a power line 27 intermittently connected to the power input unit 21, a capacitor C6 connected to a center tap of the tap transformer T1, and a tap transformer T1. Divided resistors R8, R7, R6 branched at the output terminal (stage where lamp 24 is connected) and SCR element Q4 gate-controlled by the voltage divided by the divided resistors R8, R7, R6.

When the lamp 24 is not lit, such as before the lamp 24 is turned on or when there is no lamp, or when the lamp is broken or at the end of its life, the lamp 24 is connected to both ends of the ballast 22 output. The voltage is 311V, the peak voltage of the AC input power supply (when the input power supply is 220Vrms). On the other hand, when the lamp 24 is normally turned on, the voltage across the lamp becomes lower than this 311V, and drops to the maximum lamp tube voltage value (about 130V). Thus, the igniter will operate at a high voltage of 311V.

That is, when the lamp 24 is not turned on, the voltage at both ends of the lamp is about 311V, and the voltage divided by R8, R7, and R6 becomes large. If the direction of input power is reversed, Q3 is turned off. Accordingly, when Q3 is turned on, back EMF is generated due to resonance of the primary side T1-1 of the tap transformer and C6, thereby generating a high ignition voltage at both ends of the lamp 24.

As a result, Q3 is turned off when the lamp 24 is turned on, and Q3 is turned on periodically when the lamp 24 is not lit or at no load.

-Short circuit detection part (25)

The short circuit detection unit 25 includes a resistor R21, R22, a diode D12, a capacitor C12, and a base connected at both ends of the lamp 24 in parallel to receive a charging voltage of the capacitor C12.

Input interceptor (26)

The input interrupter 26 includes: a photocoupler PC3 which receives the charging voltage of the capacitor C10 connected to the input both ends of the ballast 22 in an electrically insulated state; An SCR element Q1 which is gate-controlled by the output of the PC3 and turned on / off, the anode pole is connected to one line of the power input unit through the solenoid of the relay RL1, and the cathode pole is connected to the other line of the power input unit; A relay which operates by the solenoid of the RL1 and blocks input power from being supplied to the power line when Q1 is turned on by the signal output from the PC3, and connects the input power to the power line when Q1 is turned off. It is configured to include a switch SW.

Referring to the operation of the embodiment of the present invention having the configuration as described above are as follows.

If the output terminal is short-circuited due to incorrect wiring of the output line 27, defective socket, lamp breakage, or aging of the output line 27, no current is charged in the capacitor C12 because no current flows through R21, D12, and R22. . Without the charging voltage of C12, Q5 does not operate because the base current of Q5 is zero. Therefore, the voltage charged to the capacitor C10 through R19, D11 and R20 flows through the PC3, and at this time, the voltage charged to the capacitor C2 flows through the PC3 to conduct the SCR element Q1 to operate the relay RL1, and the RL1 operates. When the relay switch SW is switched to terminal a, the power is cut off. While the input power is off, the input power is consumed by the solenoid coil of the relay RL.

When the output stage is not shorted, when the power is applied, the voltage charged to C12 through R21, D12, and R22 becomes large, and Q5 is operated. Therefore, the current flowing through R19, D11, and R20 is not charged to C10, and Q5. PC3 does not operate because it flows through. If the PC3 does not operate, the SCR device Q1 does not operate and does not cut off the power supply.

On the other hand, when the output line 27 is short-circuited and the relay RL1 operates, the other contact of the relay RL1 is connected, and current flows through the LED1 and the resistor R9, and the LED1 is turned on, and the display lamp when the output line 27 is short-circuited. Can be used as

In addition, to supply the voltage for the transistor inside the PC3, the input power was full-wave rectified with four diodes D1, D2, D3, and D4, the ripple was removed by the capacitor C2 and the zener diode ZD1, and then supplied to the PC3 through R2. In addition, the varistor VR1 is connected in parallel to the coil of the relay RL1 to absorb the high voltage counter voltage generated when the relay RL1 is turned on and off.

In addition, condenser C1, diode D7, zener diodes ZD7, ZD8 were added for stable operation of the circuit, and added SW 'on the other side of the input power to the input power side and interworked with SW to the relay RL1. It was made. Improvement or modification of such a circuit is a matter that can be arbitrarily designed by the person skilled in the art from the technical idea of the present invention shown in Figs.

As described above, according to the present invention, when the output short-circuit state is caused due to incorrect wiring of the output line, defective socket, lamp breakage, aging of the output line, etc., the current supplied to the ballast is cut off so that no current flows to the ballast. Therefore, there is an effect that can suppress unnecessary power consumption.

Claims (3)

A circuit is added to a magnetic ballast for a high voltage discharge lamp including an igniter means for generating a pulse voltage from an AC input power source and applying the same to a lamp to light the high voltage discharge lamp. Short circuit detecting means for detecting whether the output end of the ballast including the igniter means is a short circuit state, According to the detection signal of the short-circuit detecting means, if it is detected as a short circuit state, the voltage input to the power input unit is cut off, if it is detected that the short circuit state includes an input interrupting means for connecting the input power, The input control means, A photocoupler PC3 that receives the charging voltage of the capacitor C10 connected to the input of the ballast in an electrically insulated state; An SCR element Q1 which is gate-controlled by the output of the PC3 and turned on / off, the anode pole is connected to one line of the power input unit through the solenoid of the relay RL1, and the cathode pole is connected to the other line of the power input unit; A relay which operates by the solenoid of the RL1 and blocks input power from being supplied to the power line when Q1 is turned on by the signal output from the PC3, and connects the input power to the power line when Q1 is turned off. The short circuit protection circuit of the ballast for high voltage discharge lamps characterized by including the switch SW. The method of claim 1, wherein the input control means In order to supply a voltage to the transistor inside the photocoupler PC3, further comprising a diode D1, D2, D3, D4 rectifying and smoothing the input power, and a capacitor C2 and Zener diode ZD1, Short circuit protection circuit. The method of claim 1, wherein the short circuit detection means, A condenser C12 connected across the output of the ballast, A base connected to receive the charging voltage of the capacitor C12, the transistor C5 connected to operate the PC3 when there is no charging voltage in the capacitor C12, and to operate the PC3 when the capacitor C12 has the charging voltage. Short circuit protection circuit of high voltage discharge lamp ballast.