System General Corporation

Chao-Chih Lin

Ta-Yung Yang

Ying-Chieh Su

Li Kuei Lin

Rui-Hong Lu

Chiu-Chih Chiang

Jhih-Da Hsu

Meng-Jen Tsai

Chia-Yo Yeh

Wei-Ting Wang

The present invention provides a control circuit having a multi-function terminal. The control circuit comprises a switching circuit, a sample-and-hold circuit, a detection circuit, and a comparator. The sample-and-hold circuit is coupled to the multi-function terminal for generating a sample voltage by sampling the feedback signal during a first period. The detection circuit is coupled to the multi-function terminal during a second period for generating a detection voltage. The comparator compares the detection voltage and the sample voltage for generating an over-temperature signal, wherein the over-temperature signal is couple to disable the switching signal.

Multi-function terminal of power supply controller for feedback signal input and over-temperature protection

The present invention proposes a switching controller of a flyback power converter. The switching controller includes a switching circuit, a sample-and-hold circuit, a voltage detection circuit, an oscillation circuit, and a comparator. The voltage detection circuit generates a holding signal when a level of an input voltage of the flyback power converter is lower than a low-threshold. The oscillation circuit limits the maximum frequency of switching signal. The maximum frequency is increased in response to a decrement of a modulation signal. The modulation signal correlated with a level of the input voltage is used to generate a control signal when the level of the input voltage is lower than an ultra-low-threshold. The control signal is enabled to operate the flyback power converter in continuous current mode operation. Therefore, an input capacitor can be eliminated and manufacturing cost is saved.

Switching controller for flyback power converters without input capacitor

A dual switches Flyback power converter with a wide input voltage range according to the present invention comprises an input diode and an energy-storage capacitor. The input diode can prevent the reflected voltage from the power transformer of the power converter to charge the electrolytic capacitor of the power converter. The energy-storage capacitor will store the reflected voltage and the energy of the leakage inductor of the power transformer. The energy stored in the energy-storage capacitor will be recycled to the output voltage of the power converter. Further, the input diode can be replaced by an input transistor to prevent the reflected voltage from the power transformer to charge the electrolytic capacitor.

Dual switches flyback power converter with wide input voltage range

The present invention provides a controller for a power converter. The controller comprises a PWM circuit, a detection circuit, a signal generator, an oscillation circuit, a valley-lock circuit, a timing circuit and a burst circuit. The PWM circuit generates a switching signal coupled to switch a transformer of the power converter. A feedback signal is coupled to control and disable the switching signal. The detection circuit is coupled to the transformer via a resistor for generating a valley signal in response to a waveform obtained from the transformer. The signal generator is coupled to receive the feedback signal and the valley signal for generating an enabling signal. The oscillation circuit generates a maximum frequency signal. The maximum frequency signal associates with the enabling signal to generate a turning-on signal. The turning-on signal is coupled to enable the switching signal. A maximum frequency of the turning-on signal is limited.

Switching controller with valley-lock switching and limited maximum frequency for quasi-resonant power converters

A control circuit with protection circuit for power supply according to the present invention comprises a peak-detection circuit and a protection circuit. The peak-detection circuit detects an AC input voltage and generates a peak-detection signal. The protection circuit generates a reset signal to reduce the output of the power supply in response to the peak-detection signal. The present invention can protect the power supply in response to the AC input voltage effectively through the peak-detection circuit.

Control circuit with protection circuit for power supply

A switching control circuit for a switching power converter is provided. The switching control circuit is coupled to a switching device and an auxiliary winding of a transformer. The switching control circuit includes a valley detecting circuit, a valley lock circuit, and a PWM circuit. The valley detecting circuit is coupled to receive a reflected voltage signal from the auxiliary winding of the transformer for outputting a control signal in response to the reflected voltage signal. The valley lock circuit is coupled to receive the control signal for outputting a judging signal in response to the control signal during a first period and a second period following the first period. The PWM circuit outputs a switching signal in response to the judging signal.

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Taoyuan County, Taiwan

Chao-Chih Lin