CONTROL CIRCUIT OF ISOLATED CONVERTER AND SWITCHING POWER SUPPLY, AND CONTROL METHOD FOR THE SAME

摘要

Controlling an isolated converter can include: controlling a first voltage signal across the secondary winding according to a wake-up signal to reflect change of an output voltage of the isolated converter; obtaining a second voltage signal representing the first voltage signal at the primary side; controlling the main power switch according to a detection result of the second voltage signal; generating the wake-up signal according to the output voltage and a first threshold voltage when the isolated converter is in a dynamic loading state of a normal operating mode; generating the wake-up signal according to the output voltage and a second threshold voltage when the isolated converter is in a load steady state of a standby operating mode; and generating the wake-up signal according to the output voltage and a third threshold voltage when the isolated converter is in a dynamic loading state of the standby operating mode.

主权项

1. A method of controlling an isolated converter comprising a transformer having a primary winding and a secondary winding, a main power switch coupled with said primary winding, and a freewheeling diode coupled with said secondary winding, the method comprising:
a) controlling a first voltage signal across said secondary winding according to a wake-up signal to reflect change of an output voltage of said isolated converter; b) obtaining a second voltage signal that represents said first voltage signal at said primary side of said isolated converter; c) detecting said second voltage signal and controlling said main power switch according to a detection result in order to maintain said output voltage at a predetermined value; d) generating said wake-up signal according to said output voltage and a first threshold voltage when said isolated converter is in a dynamic loading state of a normal operating mode; e) generating said wake-up signal according to said output voltage and a second threshold voltage when said isolated converter is in a load steady state of a standby operating mode; and f) generating said wake-up signal according to said output voltage and a third threshold voltage when said isolated converter is in a dynamic loading state of said standby operating mode.