Control method and circuit with indirect input voltage detection by switching current slope detection
AssigneeSystem General Corp.
InventorsTa-Yung Yang, Chien-Yuan Lin
Life of this patent
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Abstract
The present invention provides a method and a control circuit to detect an input voltage for the control and protections of a power converter. It includes a current sense circuit for generating a current signal in response to a switching current of a transformer. A detection circuit is coupled to sense the current signal for generating a slope signal in response to a slope of the current signal. A protection circuit is further developed to control the switching signal in accordance with the slope signal. The level of the slope signal is corrected correlated to the input voltage of the power converter.
Claims36
A control circuit of a power converter including an input voltage detection, comprising:
- a power transistor coupled to a transformer for switching the transformer;
- a current sense circuit generating a current signal in response to a switching current of the transformer;
- a switching circuit coupled to receive the current signal and a feedback signal to generate a switching signal for controlling the power transistor and regulating the output of the power converter;
- a detection circuit coupled to sense the current signal for generating a slope signal in accordance with a slope of the current signal;
- a signal generator generating an input-voltage signal in accordance with the slope signal;
- and
- a protection circuit coupled to control the switching signal in response to the input-voltage signal;
- wherein the input-voltage signal is corrected correlated to the input voltage of the power converter.
A control circuit of a power converter including an input voltage detection, comprising:
- a power transistor coupled to a transformer for switching the transformer;
- a current sense circuit generating a current signal in response to a switching current of the transformer;
- a switching circuit coupled to receive the current signal and a feedback signal to generate a switching signal for controlling the power transistor and regulating the output of the power converter;
- a detection circuit coupled to sense the current signal for generating a slope signal;
- and
- a protection circuit coupled to control the switching signal in response to the slope signal;
- wherein the level of the slope signal is corrected correlated to the input voltage of the power converter.
A control circuit of a power converter, comprising:
- a switching circuit generating a switching signal for controlling a power transistor and regulating the output of the power converter in response to a switching current and a feedback signal;
- a detection circuit coupled to sense the switching current for generating a slope signal;
- and
- a protection circuit coupled to control the switching signal in response to the slope signal;
- wherein the slope signal is corrected correlated to an input voltage of the power converter.
A control method of a power converter, comprising:
- generating a switching signal for controlling a power transistor in response to a switching current;
- sensing a slope of the switching current for generating a slope signal corrected correlated to an input voltage of the power converter;
- and
- controlling the switching signal in response to the slope signal.
Dependencies are inferred from the claim text.