KR960004311Y1 - Electronic ballast for fluorescent lamp - Google Patents

Abstract

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Description

Ballast Circuit for Electronic Fluorescent Lamps

1 is a block diagram of the present invention.

2 is a circuit diagram of the present invention.

* Explanation of symbols for main parts of the drawings

10: noise canceling circuit 20: rectifier circuit

30: smoothing circuit 40: voltage division circuit

50: voltage enhancing and rectifying circuit 60: smoothing and constant voltage circuit

70: copper circuit in case of oscillation and delay 70a: oscillation IC

80: output bias circuit 90: fluorescent lamp connection circuit

90a-90d: Filament NF: Noise Filter

FET ₁ , FET ₂ : Field effect transistor TR: Transistor

PT: Pulse Trans CH ₁ -CH ₄ : Output Coil

BD: Bridge Diode ZD ₁ -ZD ₅ : Zener Diode

D1-D3: Diode R ₁ -R1 ₂ : Resistance

C ₁ -C ₂₀ : condenser

The present invention relates to a ballast circuit for an electronic fluorescent lamp, and more particularly to a ballast circuit for an electronic fluorescent lamp that can be lit by connecting four fluorescent lamps to one ballast in common by oscillation.

Since the oscillation method is self-contained with a conventional general electronic ballast for ballasts, the oscillation is carried out by feeding back without using ash for oscillation separately. As the oscillation circuit is affected, the oscillation frequency changes, causing the output voltage to change and adversely affect the brightness and lifetime of the fluorescent lamp.In addition, the initial power can be disconnected due to the overcurrent supplied to the filament of the fluorescent lamp. It was a factor, and the degradation occurred around the filament, and it was uneconomical because only one fluorescent lamp was turned on in one fluorescent ballast.

Therefore, the present invention is devised to solve the above-mentioned shortcomings,

First: Even if the four fluorescent lamps of one ballast are lit,

Second: the oscillation frequency was made constant by adopting the oscillation method by the oscillation and delay start circuit.

Third: The purpose of the preheating method (SOFT START) is to extend the life of the filament of the constant brightness of fluorescent lamps, and to prevent degradation.

This will be described with reference to the accompanying drawings.

A noise canceling circuit (10) comprising a noise filter (NF) and a capacitor (C ₁ -C ₃ ) for removing the noise of the applied power (AC) and a condenser (C ₅ -C ₇ ) through the rectifier circuit (20) It is connected to a smoothing circuit 30 composed of diodes (D ₁ -D ₅ ), the smoothing circuit 30 is connected to a pulse transformer (PT), a resistor (R _9- R ₁₂ ) and a zener diode (ZD ₂ -ZD ₅ ) And a circuit for connecting the output of the field effect transistor (FET ₁ ) (FET ₂ ) and the bias circuit (80) while the capacitor (C ₈ ) (C ₉ ) is connected in parallel to the fluorescent lamp connection circuit ( 90 b) of the filament 90a-90d, and the noise canceling circuit 10 is connected to the voltage drop and rectification circuit 50 and the resistor R ₁ composed of a capacitor C ₁₀ and a bridge diode BD. Transistor (TR), resistor (R ₂ -R ₇ ), capacitor (C ₁₃ ) in smooth and constant voltage circuit 60 and oscillation IC 70a of capacitor C ₁₁ (C ₁₂ ) and zener diode (ZD ₁ ) interconnecting -C ₁₆₎ configured to be taryeo oscillation start-up and delay circuit 70 Is connected to the output and bias circuit 80 and the output and bios circuit 80 is heated with respective filaments 90a-90d through respective output coils CH ₁ -CH ₄ of the fluorescent lamp connection circuit 90. Ballast circuit for an electronic fluorescent lamp configured to be connected to a capacitor (C ₁₇ -C ₂₀ ).

Hereinafter, the operation and effects of the present invention will be described in detail with reference to the accompanying drawings.

When AC power is applied, the noise canceling circuit 10 prevents unnecessary signals from being mixed by the noise filter NF and transmits high frequency and harmonic signals generated inside the fluorescent lamp ballast to the outside through the power line. The rectifier circuit 20 and the voltage strengthening and rectifying circuit 50 are prevented and the grounding point of the capacitors C ₃ and C ₄ is grounded to make the power supply of the fluorescent lamp ballast equal to the ground potential. To apply.

Therefore, the power rectified via the rectifier circuit 20 has a low impedance alternatingly by the capacitor C ₅ of the smoothing circuit 30 to bypass various high and high frequencies in the fluorescent lamp ballast circuit (BY PASS). The capacitors (C ₆ ) (C ₇ ) and the diodes (D ₁ -D ₃ ) are charged and discharged through the DC flow of the rectified RIPPLE wave at 1/2 cycles of the capacitors (C ₈ ) ( parallel or relative to C _9), capacitor (C ₈ of the voltage dividing circuit 40 and the output bias circuit (the voltage dividing circuit 40 for supplying a direct current power to 80)) (C _9), the applied power, Since half of the power supply voltage can be obtained at the center of the condenser C ₈ (C ₉ ), half of the DC power is supplied to each of the filaments 90a-90d of the fluorescent lamp connection circuit 90.

At this time, the power supply of the fluorescent ballast in the noise canceling circuit 10 is equal to the ground (GND) potential is passed through the voltage drop and the rectifier circuit 50, the resistance of the AC (AC) of the capacitor (C ₁₀ ) The voltage is enhanced by using and the onion rectified through the bridge diode (BD) is applied to the capacitor (C ₁₁ ) (C ₁₂ ) of the smoothing and constant voltage circuit 60, the capacitor (C ₁₁ ) (C ₁₂ ) Charged and DC-driven, resistor R ₁ drops the current limit and voltage flowing to the load, and zener diode ZD ₁ energizes a current exceeding a constant voltage to maintain a constant voltage, causing the oscillation and delay start circuit 70 ) Is applied to the sawtooth wave by charging and inverting the resistor R ₃ of the oscillation and delay start circuit 70 and the capacitor C ₁₄ . Waveform is generated and a square wave ( The waveform is converted into a waveform and output through the capacitor C ₁₆ and the resistor R8. Initially, when power is applied while the capacitor C ₁₃ is discharged, the + current is the emitter of the resistor R2 and the transistor TR. The capacitor C ₁₃ is charged via the base and the resistor R ₅ .

Therefore, a current is applied to the emitter and the base of the transistor TR, and its collector current is charged to the capacitor C ₁₄ through the resistor R ₇ so that the frequency of the oscillation IC 70a is lowered and the capacitor C ₁₃ When the charging is completed, the emitter and the collector of the transistor TR are turned off so that the voltage of the capacitor C ₁₄ is charged by the resistors R ₂ and R ₃ and the oscillation IC 70a is at a normal frequency. Oscillate.

In addition, when the power is cut off, the current charged in the capacitor C ₁₃ is discharged through the resistor R ₆ .

In other words, in the initial operation, a very low voltage is applied to oscillate a low frequency, and after a predetermined time, the oscillation IC 70a oscillates at a normal high frequency.

Therefore, the square wave pulse oscillated by the oscillation IC 70a is applied to the field effect transistor FET ₁ and FET ₂ through the pulse transformer PT of the output and bias circuits 80 so that the mutual phase difference becomes 180 °. When the effect transistor FET ₁ is operated, the field effect transistor FET ₂ is turned off, and conversely, when the field effect transistor FET ₂ is operated, the field effect transistor FET ₁ is turned off (( Square wave AC signal flows through each of the output coils CH _{1 to} CH ₄ of the fluorescent lamp connection circuit 90 so that each stage of the filaments 90a to 90d and the heating capacitor C ₁₇ -C ₂₀ ) and the capacitor C ₉ of the voltage dividing circuit 40 and the fluorescent lamp connecting circuit in the reverse order after flowing through the capacitors of the voltage dividing circuit 40 via the b ends of the filaments 90a-90d. 90 f of each filament (90a-90d), each of the heating capacitor (C ₁₇ -C ₂₀ ) and each filament Cement 90a-90d flows through a stage and each output coil CH ₁ -CH ₄ .

As described above, the present invention has a low frequency during the initial operation of the oscillation oscillation and delay start circuit 70, and after a certain time, a normal high frequency is oscillated and output from the oscillation IC 70a. It is applied to the filament (90a-90d) of the fluorescent lamp connection circuit 90 and supplies a normal output at the end of preheating, thereby preventing the fall of the fluorescent lamp and disconnection of the filament, and condenser (C ₈ ) (C) of the voltage division circuit (40) ₉ ) It is an advantageous design that can be used jointly by tying four fluorescent lamp filaments in one line.

Claims (2)

Through the rectifier circuit 20, the noise removing circuit 10 including the noise filter NF and the capacitors C ₁ -C ₄ to remove the noise of the applied power AC is connected to the capacitors C ₅ -C ₇ . Voltage division circuit 40, pulse transformer (PT), and resistor (R ₉ -R) of capacitor (C ₈ ) (C ₉ ) connected in parallel via smoothing circuit (30) of diodes (D ₁ -D ₃ ). ₁₂ ), a zener diode (ZD ₂ -ZD ₅ ) is connected to an output and bias circuit 80 composed of field effect transistors (FET ₁ ) (FET ₂ ), and the noise canceling circuit 10 is connected to a voltage drop and rectification circuit ( In the conventional circuit connected to the smoothing and constant voltage circuit 60 through 50, the output of the smoothing and constant voltage circuit 60 is oscillating IC 70a for oscillating square wave pulse, transistor TR, and resistor R _2. -R ₇ ) and the oscillation and delay start circuit 70 are composed of the capacitor (C ₁₃ -C ₁₅ ) that charges and discharges, and the four output coils (CH ₁ -CH ₄ ) are output through the output and bias circuit (80). ) And the respective filaments (90a-90d) A stable opportunity for electronic fluorescent lamp, characterized in that configured to be connected to the capacitor for (C ₁₇ -C ₂₀₎ to the fluorescent lamp connected to the circuit (90). The b terminal of each of the filament (90a-90d) of the fluorescent lamp connection circuit 90 can be commonly used to connect to the midpoint of the capacitor (C ₈ ) (C ₉ ) of the voltage division circuit (40) Ballast circuit for electronic fluorescent lamps, characterized in that.