System General Corporation

Feng-Cheng Tsao

Ta-Yung Yang

Chuh-Ching Li

Rui-Hong Lu

Pei-Sheng Tsu

Tso-Min Chen

Jesse R Wang

A switching control circuit is provided for measuring and regulating an output current of a power converter. The power converter is operated under continuous current mode. A detection circuit generates a continuous-current signal and a peak-current signal by detecting a switching current of an inductive device. An integration circuit generates an average-current signal in response to the continuous-current signal, the peak-current signal and an off time of a switching signal. The switching control circuit generates the switching signal in response to the average-current signal. The switching signal is coupled to switch the inductive device and regulate the output current of the power converter. A time constant of the integration circuit is correlated to the switching period of the switching signal, therefore the average-current signal will be proportional to the output current.

Control circuit for measuring and regulating output current of CCM power converter

A switching regulator includes a switching device to switch a transformer from a primary-side to secondary side. A control circuit generates a switching signal for regulating output of the switching regulator. The control circuit includes a first circuit to generate a first signal and a timing signal by measuring a reflected signal of the transformer. A second circuit produces a second signal by integrating a current signal with the timing signal. The current signal represents a primary-side switching current of the transformer. A first feedback circuit produces a first feedback signal in response to the first signal and the reference signal, in which the reference signal is varied in response to the change of the second signal. Furthermore, a second feedback circuit generates a second feedback signal in response to the second signal. A switching control circuit generates the switching signal in response to the feedback signals.

Primary-side controlled switching regulator

A transistor drive circuit of a power converter is developed for operating in a wide voltage range. It includes an N-type high-side transistor, a P-type high-side transistor and an N-type low-side transistor. A voltage clamp device is connected to the gate of the N-type high-side transistor to limit the maximum output voltage. A detection circuit is coupled to detect the supply voltage of the transistor drive circuit to generate a disable signal in response to the voltage level of the supply voltage. The disable signal is coupled to disable the P-type high-side transistor once the voltage level of the supply voltage is higher than a threshold voltage.

Transistor drive circuit of power converter operating in a wide voltage range

The present invention provides a power converter having a phase lock circuit for quasi-resonant soft switching. The power converter includes a first circuit coupled to the feedback signal to generate a switching signal for switching a switching device and regulating the output of the power converter. A second circuit is coupled to an auxiliary winding of the transformer for generating a voltage signal in response to the voltage of the transformer. A phase lock circuit generates a control signal to enable the switching signal in accordance with the voltage signal. The switching signal further turns on the switching device in response to a valley voltage across the switching device.

Power converter having phase lock circuit for quasi-resonant soft switching

The present invention provides a switching control circuit having a valley voltage detector to achieve the soft switching and improve the efficiency of a power converter. The switching control circuit includes a control circuit coupled to the feedback signal to generate a switching signal. Through an output circuit, the switching signal drives a switching device for switching a transformer and regulating the output of the power converter. The valley voltage detector is coupled to an auxiliary winding of the transformer for generating a control signal in response to the voltage of the transformer. The control signal is used for enabling the switching signal. The switching signal further turns on the switching device in response to a valley voltage across the switching device.

Growing community of inventors

Linbian, Taiwan

Feng-Cheng Tsao