AC-DC CONVERTER AND CONTROL CIRCUIT THEREOF
First Claim
1. A controller for controlling a switch circuit of an AC-DC converter, comprising:
- a power control circuit for comparing an input current sensing signal generated by sensing an input current of the AC-DC converter and a power level control input and in response thereto generating a frequency modulation control signal, wherein the frequency modulation control signal is used to control an output power of the AC-DC converter and suppress harmonics of the input current of the AC-DC converter; and
a square wave generator connected to the power control circuit for generating a driving signal used to drive the switch circuit of the AC-DC converter according to the frequency modulation control signal, wherein a frequency of the driving signal is varied with the frequency modulation control signal, thereby suppressing the harmonics of the input current of the AC-DC converter and regulating a switching frequency of the switch circuit, and regulating the output power of the AC-DC converter.
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Accused Products
Abstract
The invention discloses a control circuit for an AC-DC converter. The control circuit includes a power control circuit for comparing an input current sensing signal generated by sensing an input current of the AC-DC converter and a power level control input and in response thereto generating a frequency modulation control signal, in which the frequency modulation control signal is used to control the output power of the AC-DC converter and suppress harmonics of the input current, and a square wave generator connected to the power control circuit for generating a driving signal used to drive the switch circuit of the AC-DC converter according to the frequency modulation control signal, in which the frequency of the driving signal is varied with the frequency modulation control signal, thereby suppressing harmonics of the input current and regulating the switching frequency the AC-DC converter, and regulating the output power of the AC-DC converter.
25 Citations
10 Claims
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1. A controller for controlling a switch circuit of an AC-DC converter, comprising:
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a power control circuit for comparing an input current sensing signal generated by sensing an input current of the AC-DC converter and a power level control input and in response thereto generating a frequency modulation control signal, wherein the frequency modulation control signal is used to control an output power of the AC-DC converter and suppress harmonics of the input current of the AC-DC converter; and a square wave generator connected to the power control circuit for generating a driving signal used to drive the switch circuit of the AC-DC converter according to the frequency modulation control signal, wherein a frequency of the driving signal is varied with the frequency modulation control signal, thereby suppressing the harmonics of the input current of the AC-DC converter and regulating a switching frequency of the switch circuit, and regulating the output power of the AC-DC converter. - View Dependent Claims (2, 3, 4)
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5. An AC-DC converter, comprising:
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a rectifier connected to an input side of the AC-DC converter for rectifying an input AC voltage into a rectified DC voltage; a filter circuit connected to an output end of the rectifier for suppressing electromagnetic interference and high-frequency noises of the input AC voltage, thereby generating a DC voltage with a waveform being analogous to the input AC voltage after being half-wave rectified or after being full-wave rectified; a transformer having a primary side connected to the filter circuit and a secondary side; a switch circuit connected to the primary side of the transformer and the filter circuit for controlling an energy transfer between the primary side and the secondary side of the transformer; a current sensor connected to the rectifier for sensing an input current of the AC-DC converter and generating an input current sensing signal accordingly; and a control circuit connected to a control terminal of the switch circuit for generating a driving signal used to drive the switch circuit according to the input current sensing signal and a power level control input, thereby suppressing harmonics of the input current of the AC-DC converter and regulating an output power of the AC-DC converter; wherein a frequency of the driving signal is varied with the input current sensing signal and the power level control input. - View Dependent Claims (6, 7, 8, 9, 10)
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Specification