Dialog Semiconductor Gmbh

Qingqing Zong

Pengju Kong

Yimin Chen

Mengfei Liu

Tao Li

Guang Feng

Juyoung Yoon

Xiyuan Liu

A flyback converter is provided that includes a high-side synchronous rectifier switch transistor. A secondary-side synchronous rectifier controller powered by a power supply voltage controls a cycling on and off of the high-side synchronous rectifier switch transistor. An active control of the charging of the power supply voltage uses an auxiliary capacitor that is charged from a charge source while a power switch transistor in a first switching state. When the power switch transistor is in a second switching state that is the complement of the first switching state, the active control coupes the auxiliary capacitor to a power supply capacitor that stores the power supply voltage.

High-side synchronous rectifier driver with reduced controller power supply charging efficiency and reduced EMI

A flyback converter is provided that dynamically adjusts a drain threshold voltage for a current cycle of a synchronous rectifier switch transistor based upon operating conditions in a previous cycle of the synchronous rectifier switch transistor. A differential amplifier drives a gate voltage of the synchronous rectifier switch transistor during an on-time of the current cycle so that a drain voltage of the synchronous rectifier switch transistor equals the drain threshold voltage during a regulated portion of the current cycle.

Adaptive gate regulation for a synchronous rectifier flyback converter

A system for turning off a synchronous rectifier (SR) based on a primary switch (PS) turn-on detection in a flyback converter having a primary-side and a secondary-side is disclosed. The system comprises the PS on the primary-side, the SR on the secondary-side, a spike detector, and a SR controller. The SR is configured to produce a drain-to-source voltage (V). The spike detector is in signal communication with an output capacitor (C) on the secondary-side and the spike detector is configured to detect a voltage spike of an output voltage (V) across the Cthat is indicative of the PS being turned-on. The SR controller is in signal communication with the SR and the spike detector and the SR controller is configured to turn-off the SR based on the spike detector detecting the voltage spike of the V.

System for turning off a synchronous rectifier based on a primary switch turn-on detection

A flyback converter is disclosed having a secondary side controller that generates an input current for an optocoupler diode by driving a variable resistor with a control voltage. The secondary side controller varies a variable resistance for the variable resistor to compensate for current transfer ratio gain variations for the optocoupler.

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Campbell, CA, United States of America

Qingqing Zong