KR100597999B1 - Lighting circuit of electronic form stabilizer for fluorescent lamp - Google Patents

Abstract

The present invention relates to a lighting circuit of an electronic ballast for a fluorescent lamp, the purpose of which is to prevent the blackening phenomenon caused by a back-up pulse when the lamp is turned on, and to maintain the lighting of the lamp more stably to extend the service life of the lamp The present invention provides a lighting circuit for an electronic ballast for a fluorescent lamp having a soft start circuit. The configuration of the present invention for achieving the above object is a surge suppression unit for removing the surge (Surge) included in the signal output through the power supply unit, a constant voltage unit for maintaining and outputting the voltage of the surge suppression unit at a constant voltage; It is driven by receiving the voltage of the constant voltage unit, the soft start unit consisting of an oscillation control unit for outputting the cathode preheating current by varying the frequency to zero crossing method, and receives the output signal of the soft start unit to generate a predetermined resonance to generate a fluorescent lamp A resonator for turning on; At the end of the life of the lamp includes a protection unit to block the lighting of the lamp and at the same time block the operation of the soft start unit, according to the present invention is configured, the occurrence of the blackening phenomenon due to a back-up pulse when the lamp is turned on In addition to preventing and maintaining the lighting of the lamp more stably, there is an effect that can extend the service life of the lamp.

Soft start part, protection part, oscillation control part

Description

Lighting circuit of electronic ballast for fluorescent lamps {LIGHTING CIRCUIT OF ELECTRONIC FORM STABILIZER FOR FLUORESCENT LAMP}

1 is a block diagram of an electronic ballast lighting circuit for a fluorescent lamp according to the present invention.

2 is an electronic ballast lighting circuit diagram for a fluorescent lamp according to the present invention.

3 is an operating state diagram illustrating an impedance curve of a frequency and a resonator inductor in the oscillation controller of FIG. 1.

The present invention relates to a lighting circuit of an electronic ballast, and more particularly, a soft start unit (circuit) for preventing blackening occurring in association with a counterweight pulse when a fluorescent lamp is turned on, and for extending the service life of the lamp. The lighting circuit of the ballast for fluorescent lamps provided.

In general, the ballast acts as a starting device to turn on the lamp because it supplies an initial starting voltage to the fluorescent lamp to facilitate the discharge of the lamp.

These lamps have a negative voltage-current characteristic, so when the initial lamp is turned on, the voltage continuously decreases and the current rises, eventually destroying the lamp. In order to prevent this phenomenon, a ballast is required. After lighting, the ballast supplies a constant voltage to the lamp to limit the current.

The electronic ballast used for this purpose is to convert the commercial power frequency (60Hz) into a frequency of approximately 30 to 50kHz using a high frequency conversion circuit and drive it as a power source for the lamp, which has many advantages over conventional ballasts. Although there is a problem in the surge voltage, the protection circuit is built in. Nevertheless, there is a problem in that the lamp life is shortened due to frequent blackening phenomena associated with the counterweight pulse at start-up due to the high voltage supply at the initial lighting. have.

An object of the present invention is to provide a fluorescent lamp having a soft start unit (circuit) which can prevent the blackening phenomenon due to a counter-pulse pulse when the lamp is turned on, and can stably maintain the lamp to extend the service life of the lamp. It is to provide a lighting circuit of an electronic ballast.

Another object of the present invention is to provide a lighting circuit of an electronic ballast for a fluorescent lamp which can protect the lighting circuit by completely preventing various circuit components of the ballast from being damaged by overcurrent at the end of the lamp life.

The present invention for achieving this object is;

Surge suppression unit for removing surge included in the signal output through the power supply unit, a constant voltage unit for maintaining and outputting the voltage of the surge suppression unit at a constant voltage and is driven by the voltage applied to the constant voltage unit, frequency Resonator for turning on the fluorescent lamp and the lifetime of the lamp to generate a predetermined resonance by receiving a soft start unit consisting of an oscillation control unit for outputting the cathode preheating current by zero crossing method by varying It characterized in that it comprises a protection unit for shutting off the lighting of the lamp at the end and at the same time block the circuit operation of the soft start unit.

In addition, the constant voltage unit of the soft star unit operates with a voltage passing through the surge suppression unit, and the resistor R1, the resistor R4, the zener diode D7, and the collector terminal are connected in series with each other, and the resistor R1 and the resistor R4. One end is connected to the emitter terminal of the transistor Q2 connected between the other end, and the other end thereof is connected in parallel with the capacitor C11 connected to the anode end of the zener diode D7 and the capacitor C11 in parallel. And a zener diode D6 for maintaining a constant voltage.

In addition, the oscillation control unit of the soft start unit may include an initial voltage forming unit configured to form an initial voltage for oscillation with a capacitor C10 and a resistor R10, and a gate terminal receiving a voltage of the resistor R10 of the initial voltage forming unit. FET Q3 is switched on when current flows between the drain (D) and source (S) terminals as the trigger is turned on, and the oscillation frequency as the FET Q3 is switched on. A phase setting unit configured to determine a phase, a phase output unit comprising FETs Q1 and FETs Q4 which start oscillation through the frequency setting unit and output phases opposite to each other; It characterized in that it comprises an integrated circuit (IC) for controlling the.

In addition, the frequency setting unit is characterized by consisting of a resistor (R7), a resistor (R8) and a capacitor (C13) connected in series between pins 2 and 4 of the integrated circuit (IC).

In addition, the oscillation frequency of the oscillation control unit is initially output at a high frequency, characterized in that the normal frequency is maintained at 44.8KHz.

In addition, the protection unit detects the voltage induced on the secondary side of the inductor connected to the integrated circuit (IC) output terminal pin 6 through the resistor (R13) to detect the end of the life of the lamp through the gate (G) of the silicon control rectifier (Q6). The circuit for the soft start unit is cut off by applying a trigger signal to a terminal.

With reference to the accompanying drawings, the lighting circuit of the electronic ballast for fluorescent lamps according to the present invention will be understood by the embodiments described in detail.

1 is a block diagram of the electronic ballast lighting circuit for a fluorescent lamp according to the present invention, Figure 2 is a circuit diagram for electronic ballast lighting for a fluorescent lamp according to the present invention. FIG. 3 is an operating state diagram illustrating an impedance curve of a frequency and an inductor of a resonator in the oscillation controller of FIG. 1.

As shown in FIG. 1, the lighting circuit of the electronic ballast of the present invention receives a normal AC power and converts the predetermined DC voltage into a power supply unit 100 and outputs a signal output through the power supply unit 100. The surge suppression unit 200 for removing surge included in the surge, and the constant voltage unit 300 for filtering the primary stable signal and maintaining a constant voltage through the surge suppression unit 200 and controlling the output. The oscillation control unit 400 receives a predetermined voltage supplied from the constant voltage unit 300 and outputs the variable frequency, and implements LC resonance through the output signal of the oscillation control unit 400 to provide a control signal to the lamp. The time delay driver 700 and the lamp 800 which control the resonator 500 to supply and the relay A switching contact for shorting and opening the filament P of the lamp 800. Lamp at the end of its life) It is configured to include a stage protection unit 600. The soft start unit (circuit) 900 of the present invention is configured to include the constant voltage unit 300 and the oscillation control unit 400 described above.

Referring to FIGS. 2 and 3, the power supply unit 100 rectifies and outputs the AC power of the normal 220 [V] 60 [Hz] through the rectifying unit D1 after passing the surge removal and the filter unit. The predetermined voltage outputted through the power supply unit 100 removes surge and filters the surge suppressor 200. The surge suppression unit 200 includes a switching diode D2, a capacitor C8, a capacitor C12, and a switching diode D15 in series.

The constant voltage unit 300, which is one of the components of the soft start unit 900 described with reference to FIG. 1, is intended to maintain and output a predetermined voltage applied through the surge suppression unit 200 at a stable constant voltage. A resistor R1, a resistor R4, a zener diode D7 and a collector terminal connected in series with each other are connected to the emitter E terminal of the transistor Q2 connected between the resistor R1 and the resistor R4. The other end thereof includes a condenser C11 connected to the anode end of the zener diode D7 and a zener diode D6 connected in parallel with the condenser C11. Meanwhile, the base B terminal of the transistor Q2 is connected between the resistor R4 and the diode D7.

The oscillation control unit 400, which is another component of the soft start unit 900, is a frequency variable circuit operated by receiving a constant DC voltage output through the constant voltage unit 300. The gate terminal G is triggered on by receiving the initial voltage forming unit 420 formed of the C10 and the resistor R10 and the voltage of the resistor R10 of the initial voltage forming unit 420. FET Q3 that is switched on when current is conducted between the drain D and source S terminals, and a frequency setting unit 440 that determines an oscillation frequency as the FET Q3 is switched on. And a phase output unit 460 including FETs Q1 and FETs Q4 which start oscillation through the frequency setting unit 440 and output phases opposite to each other, and the frequency setting unit 440. And an integrated circuit (IC) for controlling input and output of the phase output unit 460.

On the other hand, the oscillation frequency controlled through the integrated circuit (IC) is determined according to the following equation ①, more specifically, the frequency setting unit 440 for determining such an oscillation frequency is the resistance (R7) and It is determined through the resistor R8 and the capacitor C13.

------------- ①

------------- ①

However, since the resistor R8 constitutes a circuit together with the FET Q3, when the FET Q3 operates, the internal resistance of the FET Q3 together with the diode D5 is combined with the resistor R8 to actually produce the circuit. The resistance (R) value is as shown in ② below.

(Ω)---------------------②

(Ω) --------------------- ②

Here, the initial voltage for the frequency oscillation is the voltage applied to the capacitor (C10) and the resistor (R10) of the initial voltage forming unit 420 connected in series with the same voltage across the diode (D6) of the constant voltage unit 300. In this case, the voltage between both ends of the resistor (R10) is the gate (G) signal of the FET (Q3) until the voltage (Vcc) of the diode (D6) is completed charging the capacitor (C10) through the resistor (R10) It acts as a voltage and the synthesis resistance at this time is as shown in the above formula ②.

However, the gate G voltage (voltage across the resistor R10) of the FET Q3 does not immediately disappear at the moment when the charging of the capacitor C10 is completed, but the delay time set in the delay time driver 700 to be described later. As the current gradually decreases and disappears during the delay time, the current of the FET Q3 also becomes proportional to the current, and the internal resistances Rq and Rd gradually increase to the opposite, and eventually become infinity, and the value of the synthesized resistance R is almost zero. Starting from the state, only the resistance (R8) value remains.

]에서 끝나게 된다.In this state, the oscillation frequency starts high initially and gradually decreases to a normal frequency [

Ends in].

The operating characteristics of the oscillation frequency will be described in more detail with reference to the frequency curve of FIG. 3 and the impedance curve of the coil (hereinafter referred to as inductor L) in more detail. The tube current of the lamp 800 flowing through (L) starts very little due to the increase in impedance, and eventually operates as if zero crossing is applied.

On the other hand, as described above, at the time of frequency oscillation, the FET Q1 and the FET Q4 operate in the opposite phase with their phases reversed at 0 ° and 180 °, respectively.

The resonator 500 is to turn on the lamp 800 by using the LC resonance by the oscillation frequency as described above, the L (inductor) is composed of the primary winding and the secondary winding, the primary winding is One end is connected to pin 6 of the output terminal of the integrated circuit (IC), the other end is connected to the filament (P) No. 1 of the lamp 800 and the secondary winding is the source (S) of the FET (Q4) The terminal is connected to the time delay driver 700 through a resistor (R13) and a resistor (R9) for detecting the voltage drop in the state at the end of life.

In addition, the C (capacitor) corresponds to a capacitor C5 and a capacitor C6 synthesized when the relay A is driven, and a capacitor C6 connected in series with the inductor L when the relay A is returned. ), The capacitor (C5) is connected to the number 4 pin of the filament (P) through the filament (P) pin 2 of the lamp 800 and the relay (A) contact a1, the capacitor (C6) is filament ( P) Pins 2 and 3 are connected at both ends, respectively, and resistor (R2) is connected in parallel.

The time delay driver 700 includes a relay A including the switch contacts a1 and a2, and a relay driver 720 for driving the relay A. The relay driver 720 includes the FET Q5. A resistor R16 connected to the drain D terminal, a resistor R16 connected to the source S terminal, and a resistor R16 connected to the gate G terminal and the other end connected to the ground GND, and a diode ( 16) and a capacitor C14 connected in series with the resistor R16, and a resistor R15 and a transistor Q8 configured between the source terminal of the FET Q5 and one terminal of the relay. The time delay driver 700 is configured to switch on / off the relay A contacts a1 and a2 of the condenser C5 and the condenser C6 of the resonator 500, or to synthesize the resonator 500. Only the inductor L and the capacitor C6 are connected in series.

The protection unit 600 is a circuit for blocking the circuits for protection of the lighting circuit including the oscillation control unit 400 and the time delay driver 700 at the end of the life of the lamp 800, the oscillation control unit 400 A silicon controlled rectifier (SCR) Q6 connected to the cathode terminal of the diode D10 and an anode terminal connected to the resistor R5 having one end connected to the first pin of the integrated circuit IC, and the lamp 800 of the lamp 800. At the end of life, the capacitor C15, the diode D8, and the oscillation control unit 400 for inducing the resistor R13 to take the rising voltage induced on the secondary side of the inductor L and the resistor R13. It is configured to cut off the circuit of the resistor R13 connected in series with the resistor (R13), and to filter the gate (g) terminal of the silicon controlled rectifier (SCR) (Q6) configured to input the trigger signal Consisting of a capacitor (C17), a resistor (R17), a resistor (R14), and a zener diode (D13). .

In addition, when a high voltage is applied to the resistor R13, the zener diode D12, the resistor R19, the capacitor C18, and the field effect transistor FET are configured to block the circuit operation of the time delay driver 700. It consists of (Q7).

Reference numeral 920 denotes a configuration of the capacitors C7 and C16 charged and corresponding to the operation of the field effect transistor (FET) Q1 and the field effect transistor (FET) Q4.

Hereinafter, with reference to FIGS. 1 to 3, the cathode preheating current is substantially zero-crossed by a soft start, that is, a main core technology of the electronic ballast lighting circuit for the fluorescent lamp of the present invention, that is, a frequency variable method in the oscillation controller 400. It will be described in detail the operating relationship and the effects that can be flowed into the.

First, a current flows through the resistor R10 and the capacitor C10 by the voltage Vcc of the operating power supply constant voltage unit 300 at the moment of supplying power, and a voltage drop occurs at both ends of the resistor R10. Since the generated voltage drop acts as the gate G voltage of the FET Q3, the FET Q3 operates to flow a drain current.

The drain current flows to the source S through the resistor R7 and the diode D5, and the internal resistances of the FET Q3 and the diode D5 are almost short.

In this case, since the FET Q3 and the diode D5 are connected in parallel, in this case, the resistor R8 is reduced to almost zero ohm state, and thus the oscillation frequency f is significantly increased. When the oscillation frequency f increases, the choke coil: the impedance of the inductor L increases, so the tube current of the lamp flowing through the choke coil: the inductor L starts at about zero. Done.

In this state, when the charging is completed in the capacitor C10 after the predetermined delay time set by the time delay driver 700, and no current flows, the voltage drop of the resistor R10 disappears and at the same time, the FET The operation of Q3 is stopped.

When the operation of the FET Q3 is stopped in this way, the internal resistance of the FET Q3 and the diode D5 is increased to become infinity, leaving only the resistor R8. At this time, the oscillation frequency is the resistance R7 and the resistor R8. And the capacitor C13.

Therefore, at the beginning of the oscillation, the frequency is very high and gradually decreases to return to the normal frequency (44.8 kHz in the embodiment of the present invention).

As described above, the tube current of the lamp 800 is resonated as the current starts at almost zero and reaches the rated value as if the zero crossing is applied, while starting at a high frequency and gradually decreasing to return to a normal frequency. The lamp 500 is operated by the voltage applied through the unit 500, and the effect can be securely turned on without giving a burden to the lamp 800. In addition, at the end of the life of the lamp 800, the protection unit 600 operates to block the operation of the soft start unit (circuit) 900, thereby protecting the circuit.

As described above, embodiments of the present invention have been described in detail, but the scope of the present invention is not limited thereto, and the scope of the present invention extends to the range substantially equivalent to one embodiment of the present invention.

 According to the present invention, the soft start circuit is implemented and operated, thereby preventing blackening due to a counter-pulse when the lamp is turned on and maintaining the lamp lighting more stably, thereby extending the service life of the lamp. There is.

In addition, another object of the present invention is to effectively prevent the damage of various circuit components of the ballast due to the overcurrent at the end of the lamp life has the effect that can be stably protect the lighting circuit.

Claims (6)

delete Surge suppression unit for removing surge included in the signal output through the power supply unit, a constant voltage unit for maintaining and output the voltage of the surge suppression unit at a constant voltage and is driven by the voltage applied to the constant voltage unit, frequency A soft start unit comprising an oscillation control unit for outputting a negative electrode preheating current by a zero crossing method, and a resonance unit for turning on a fluorescent lamp by generating a predetermined resonance by receiving an output signal of the soft start unit; At the end of the life of the lamp and the protection of the circuit and at the same time includes a protection unit for blocking the circuit operation, The constant voltage portion of the soft star portion operates with a voltage passing through the surge suppression portion, and a resistor R1, a resistor R4, a zener diode D7, and a collector terminal are connected between the resistor R1 and the resistor R4. One end is connected to the emitter E terminal of the transistor Q2 connected to the other end thereof, and the other end thereof is connected to the capacitor C11 connected to the anode terminal of the zener diode D7 and the capacitor C11 in parallel to be connected to a constant voltage. A circuit for lighting an electronic ballast for a fluorescent lamp, comprising: a zener diode (D6) for holding a light source. The method of claim 2, The oscillation control unit of the soft star unit includes an initial voltage forming unit configured to form an initial voltage for oscillation of the capacitor C10 and a resistor R10; FET Q3 that is switched on when a current flows between the drain (D) and source (S) terminals as the gate terminal (G) is triggered on by receiving the resistance (R10) voltage of the initial voltage generator. )Wow, A frequency setting unit determining an oscillation frequency as the FET Q3 is switched on; A phase output section including FETs Q1 and FETs Q4 which simultaneously start oscillation through the frequency setting section and output phases opposite to each other; And an integrated circuit (IC) for controlling the input / output of the frequency setting section and the phase output section. The method of claim 3, wherein The frequency setting unit includes a resistor R7, a resistor R8, and a capacitor C13 connected in series between pins 2 and 4 of the integrated circuit IC, and a lighting circuit of an electronic ballast for a fluorescent lamp. . The method of claim 3, wherein The oscillation frequency of the oscillation control unit is initially output at a high frequency, the lighting circuit of the electronic ballast for fluorescent lamps, characterized in that the normal frequency is maintained at 44.8KHz. The method of claim 2, The protection unit senses the voltage induced on the secondary side of the inductor (L) connected to the output terminal 6 of the integrated circuit (IC) at the end of the lamp life through the resistor (R13) to the gate of the silicon control rectifier (Q6) (g) And a trigger signal applied to a terminal to cut off the circuit of the soft start unit.

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