Systems and methods for regulating power conversion systems with output detection and synchronized rectifying mechanisms

摘要

System and method for regulating a power conversion system. An example system controller includes: a first controller terminal and a second controller terminal. The system controller is configured to: receive an input signal at the first controller terminal and generate a first drive signal at the second controller terminal based on at least information associated with the input signal to turn on or off a transistor to affect a current associated with a secondary winding of the power conversion system. The system controller is further configured to: in response to the input signal changing from a first value larger than a first threshold to a second value smaller than the first threshold, change the first drive signal from a first logic level to a second logic level to turn on the transistor.

主权项

1. A system controller for regulating a power conversion system, the system controller comprising:
a first controller terminal; and a second controller terminal; wherein the system controller is configured to:
receive an input signal at the first controller terminal; andgenerate a first drive signal at the second controller terminal based on at least information associated with the input signal to turn on or off a transistor to affect a first current associated with a secondary winding of the power conversion system; wherein the system controller is further configured to:
in response to the input signal changing from a first value larger than a first threshold to a second value smaller than the first threshold, change the first drive signal from a first logic level to a second logic level to turn on the transistor;in response to the input signal changing from the second value to a second threshold, change the first drive signal to keep the input signal approximately at the second threshold; andin response to the input signal becoming larger than a third threshold, generate the first drive signal at the first logic level to turn off the transistor.