Leadtrend Technology Corporation

Wei Cheng Su

Chun Hsin Li

Ruei Jhih Jheng

Chung-Wei Lin

Hsin Hung Lu

Hung Ching Lee

Chi Pin Chen

A PFC power converter includes a power switch and an inductive device. A compensation signal is provided in response to an output voltage of the PFC power converter. An adapted compensation signal is provided in response to an ON time of the power switch and the compensation signal, to make the adapted compensation signal, the ON time, and the adapted compensation signal fit a predetermined correlation. The ON time of the power switch is determined in response to the adapted compensation signal. The PFC power converter is capable of achieving high PF when operating in discontinuous conduction mode.

Control method and power controller for power factor correction

A dimming controller is capable of receiving a dimming signal to dim light-emitting device no matter the dimming signal is of DC or of PWM. A type identifier identifies whether the dimming signal received from an input node is of DC or of PWM. A multiplexer with an output is controlled by the type identifier and configured to provide at least a DC signal path and a PWM signal path both coupled between the input node and the output. The type identifier makes the multiplexer enable the DC signal path and interrupt the PWM signal path if the dimming signal is identified as of DC, and makes the multiplexer enable the PWM signal path and interrupt the DC signal path if the dimming signal is identified as of PWM.

Dimming controllers and dimming methods capable of receiving PWM dimming signal and DC dimming signal

A dimming controller is capable of receiving a dimming signal to dim light-emitting device no matter the dimming signal is of a first type or of a second type. A type identifier identifies whether the dimming signal received from an input node is of the first type or of the second type, to accordingly generate a selection signal. A signal converter generates a first signal in response to the dimming signal, and the first signal is of the first type. A multiplexer has two inputs receiving the first signal and the dimming signal respectively, and, in response to the selection signal, forwards one of the first signal and the dimming signal to a driver driving the light-emitting device.

A PWM controller in a switching mode power supply provides to a power switch a PWM signal determining an ON time and an OFF time. A peak detector detects a voltage peak of a line voltage generated by rectifying an alternating-current input voltage. An OFF-time control unit controls the PWM signal and determines the OFF time in response to a compensation voltage, which is in response to an output voltage of the switching mode power supply. An ON-time control unit controls the PWM signal and determines the ON time in response to the compensation voltage and the voltage peak. The ON-time control unit is configured to make the ON time not less than a minimum ON time, and the minimum ON time is determined in response to the voltage peak.

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Zhubei, Taiwan

Wei Cheng Su