Drive circuit of fluorescent tube

Abstract

The invention discloses a drive circuit of a fluorescent tube, which comprises a resonance module, a tube module, a detection device and a controller, wherein the resonance module comprises a primary side and a secondary side so as to convert the electric power of input voltage received by the primary side into an AC signal and output the AC signal from the secondary side; the resonance module also comprises a transformer, and a primary side of the transformer is provided with two connecting ends and a central tap end; the tube module comprises a plurality of tubes and is coupled to the secondary side of the resonance module so as to receive the AC signal; the detection device and the tube module are connected in series to the secondary side of the resonance module; one end of the detection device is connected with a reference potential end, and the detection device generates a current detection signal and a protection feedback signal according to current flowing through the tubes; the controller comprises two semiconductor switches which are mutually connected through one end of each semiconductor switch, and the other ends are respectively coupled to the two connecting ends of the primary side of the transformer; a base pin of the controller receives the current detection signal so as to achieve feedback control, while the other base pin receives the protection feedback signal so as to achieve protection control, thereby simplifying the circuit design.

Description

technical field [0001] The invention relates to a fluorescent tube driving circuit, in particular to a multi-lamp driving circuit with built-in MOSFET (Metal Oxide Semiconductor Field Effect Transistor). Background technique [0002] The LCD panel backlight device uses a high-frequency AC sine wave power supply to supply the energy for the cold cathode ray lamp (CCFL, Cold Cathode Fluorescent Lamp) to emit light, so a DC-to-AC converter circuit (DC / AC Inverter) is used to achieve energy conversion the goal of. A general cold cathode ray lamp drive circuit uses a resonant module to convert a DC voltage into an AC voltage to drive a cold cathode ray lamp to emit light, and detects the driving voltage and current of the cold cathode ray lamp through a voltage and current detection circuit. drive current. A pulse width modulation (PWM, Pulse Width Modulated) controller receives the voltage detection signal and the current detection signal for stabilizing the light emission of ...

AI Technical Summary

Problems solved by technology

However, the number of pins of the PWM controller and the number of electronic components used are still too many, so how to reduce the number of pins of the PWM controller and the number of electronic components to further simplify the circuit design is still the current cold cathode ray lamp. An important direction for the research and development of tube drive circuits

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