Power Forest Technology Corporation

Ju-Lin Chia

Chih-Hsiung Hsu

A frequency-jitter-controller for a power-converter is provided, and which includes a first and a second capacitance units, a first and a second charge-discharge control units, a comparing unit and a control unit. Both capacitance units are charged to a crossing-voltage during a charging phase and discharged to a reference voltage and a clamp voltage respectively during a discharging-phase in response to operations of both charge-discharge control units. The comparing unit outputs a pulse signal, compares voltages of both capacitance units during the charging phase, and compares the voltage of the first capacitance unit and the reference voltage during the discharging phase. The control unit generates a frequency jitter control signal according to the pulse signal to adjust a rising rate of the voltage on the second capacitance unit, so as to change a frequency of the pulse signal, and thus reduce EMI generated by switching switch-elements in the power-converter.

Frequency jitter controller for power converter

A power conversion apparatus and an over current protection (OCP) method thereof are provided. The OCP method includes generating a pulse-width-modulation (PWM) signal according to a loading status of an electronic device, so as to switch a power switch in the power conversion apparatus and thus making the power conversion apparatus providing an output voltage to the electronic device; generating an OCP reference signal with variable slope according to a feedback signal related to the loading status of the electronic device and a system operation voltage of a PWM controller chip in the power conversion apparatus that is used for generating the PWM signal; and comparing a sensing voltage corresponding to a current following through the power switch on a resistor, and the OCP reference signal with variable slope to determine whether to activate an OCP mechanism to control the PWM controller chip whether to generate the PWM signal.

Power conversion apparatus and over current protection method thereof

A heterodyne dual-slope frequency generation method for the load change of the power supply, which comprises a power transformer, a feedback control circuit, and a dual-slope charge-discharge circuit. The power supply generates different charge current to fit different operating mode through the feedback control circuit, feedback voltage generated into power transformer, and passes through the dual-slope charge-discharge circuit in accordance with the different outer load device and the different outer voltage rising speed. When the outer loading is changed, the feedback control circuit detects error voltage, feeds through power transformer, further changes the supplied current, and finally automatically adjusts the driving current and the output power.

Heterodyne dual slope frequency generation method for the load change of power supply

A power conversion apparatus with adjustable leading-edge-blanking (LEB) time and an over current protection (OCP) method thereof are provided. In the OCP method, a pulse-width-modulation (PWM) signal is generated according to the loading status of an electronic device to switch a power switch in the power conversion apparatus and thus the power conversion apparatus to supply an output voltage to the electronic device. A variable or fixed LEB signal is generated according to the PWM signal and the rising and falling edges of a spike signal induced at turn-on instant of the power switch. The PWM signal is constantly/continuously generated to switch the power switch during an enabling period/phase of the variable or fixed LEB signal, and whether an over current is produced in the power conversion apparatus is constantly detected to determine whether to activate an OCP mechanism during a disabling period/phase of the variable or fixed LEB signal.

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Hsinchu, Taiwan

Ju-Lin Chia