High frequency power source control circuit and protective circuit apparatus
First Claim
1. A high frequency power source control circuit, comprising:
- an active power factor corrector, which has input terminals for receiving an AC power and has functions of power factor correcting and voltage boosting;
a PWM (Pulse Width Modulation) and high frequency power output circuit, which is coupled to the active power factor corrector and is a PWM integrated circuit as a main circuit;
a DC power supply circuit coupled to the active power factor corrector;
a DC load system, wherein the DC power supply circuit supplies a DC power to the load system; and
a starting circuit, wherein the DC load system feeds a signal back to the starting circuit, and when the load system receives the DC power, the load system generates a voltage and outputs the voltage to the PWM and high frequency power output circuit in order to start CCFL tubes or EEFL tubes and offer each of the CCFL tubes or EEFL tubes a stable high frequency voltage or a stable high frequency current, such that each of the CCFL tubes or EEFL tubes gets an appropriate compensation current to obtain an optimal emitting efficiency and enhance an emitting quality.
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Accused Products
Abstract
A precision voltage control circuit applicable to a PWM (Pulse Width Modulation) circuit can offer CCFL (Cold Cathode Fluorescent Lamp) or EEFL (External Electrode Fluorescent Lamp) tubes a stable high frequency voltage or current, so that each CCFL or EEFL tube can get an appropriate compensation current and an optimal emitting efficiency and enhance its emitting quality. The circuit also has an overload current, low current, and overload voltage and low voltage protective circuit to protect the CCFL or EEFL tubes from being injured. The circuit can also be applied to the TFT LCD TV or other large LCD panels, and develops the best display effect of each LCD tube.
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Citations
49 Claims
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1. A high frequency power source control circuit, comprising:
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an active power factor corrector, which has input terminals for receiving an AC power and has functions of power factor correcting and voltage boosting;
a PWM (Pulse Width Modulation) and high frequency power output circuit, which is coupled to the active power factor corrector and is a PWM integrated circuit as a main circuit;
a DC power supply circuit coupled to the active power factor corrector;
a DC load system, wherein the DC power supply circuit supplies a DC power to the load system; and
a starting circuit, wherein the DC load system feeds a signal back to the starting circuit, and when the load system receives the DC power, the load system generates a voltage and outputs the voltage to the PWM and high frequency power output circuit in order to start CCFL tubes or EEFL tubes and offer each of the CCFL tubes or EEFL tubes a stable high frequency voltage or a stable high frequency current, such that each of the CCFL tubes or EEFL tubes gets an appropriate compensation current to obtain an optimal emitting efficiency and enhance an emitting quality. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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- 33. A CCFL or EEFL protective circuit, where in a secondary coil of a high frequency transformer is serially coupled to one or multiple high-voltage condensers, a CCFL (Cold Cathode Fluorescent Lamp) or EEFL, one or multiple bridge rectifiers and one or more measurement resistors to form a basic combination of a CCFL or EEFL set.
Specification