Leadtrend Technology Corporation

Jun-Hao Huang

Chung-Wei Lin

Ming-Chang Tsou

Tsung-Chien Wu

Hsin-Hung Lu

San-Yi Li

Chun-Hsin Li

Hung-Ting Hsu

An operation power source for an operation power source supplying power to a synchronous rectifier controller is charged according to the invention. The synchronous rectifier controller controls a synchronous rectifier in response to a channel signal of the synchronous rectifier, generating SR ON times and SR OFF times. It is determined whether the channel signal resonates in a first SR OFF time, to provide an oscillation record accordingly. In a second SR OFF time after the first SR OFF time, in response to the oscillation record, a portion of resonance energy that causes the channel signal resonating is directed to charge the operation power source.

Synchronous rectifiers and charging methods used therein

A method of switching operational modes of a power converter includes starting up a primary controller applied to the power converter to make the power converter operate in a normal mode; a secondary controller applied to the power converter detecting an output voltage of a secondary side of the power converter and the primary controller detecting an operational frequency of the power converter; if the operational frequency of the power converter is lower than a predetermined frequency and satisfies a first frequency condition, the primary controller controlling the power converter to enter a sleep mode; and when the power converter enters the sleep mode and the output voltage is lower than a trigger voltage, the secondary controller making the primary controller to control the power converter turned on.

Method of switching operational modes of a power converter

The invention discloses a control method in use of a synchronous rectifier controller, controlling a synchronous rectifier in a power supply supplying power a load. The synchronous rectifier is turned ON in response to a terminal signal of the synchronous rectifier. An ON-time of the synchronous rectifier is made not less than a minimum ON-time. A detection result in association with the load is provided, for determining the minimum ON-time. The minimum ON-time is a first period when the detection result indicates the load as a first load, and a second period, shorter than the first period, when the detection result indicates the load as a second load heavier than the first load.

Control methods for changing minimum on-time of synchronous rectifier and related synchronous rectifier controllers

A synchronous rectifier applied to a secondary side of a power converter includes a forbidden turning-on time generation circuit, a green mode signal generation circuit, and a controller. The forbidden turning-on time generation circuit generates a forbidden turning-on time corresponding to the secondary side according to a synchronous signal of the secondary side. The green mode signal generation circuit enables a green mode signal when the forbidden turning-on time is greater than a reference value by at least one time, and disables the green mode signal when the forbidden turning-on time is continuously less than a reference value by a predetermined number of times. The reference value is changed with an output voltage of the secondary side. The controller enters a green mode when the green mode signal is enabled, and leaves the green mode when the green mode signal is disabled.

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Hsinchu County, Taiwan

Jun-Hao Huang