High-Efficiency Self-Driven Technique for Non-Isolated 12V VRs

The concept of self-driven for synchronous rectifier devices was widely used in isolated topologies, where the voltage across the secondary winding can be used, or partially used as the gate driving source for the rectifiers. The main benefit of self-driven is that the driving circuit is simplified, which results in a low cost solution. However, in conventional buck converter, which is the dominant member in 12V VRM family, it is very difficult to adopt selfdriven scheme. The proposed self-driven topologies are basically buck-derived multi-phase interleaving soft switching topologies, which can use self-driven easily, save driving loss and achieve ZVS. A prototype of 4-phase 12V VRM delivering 1.3V/70A output power is implemented to show its advantages (Cost, Size and Efficiency) over the conventional multi-phase buck converter.This invented circuit is really simple and high efficient. It can be a very good candidate to be used in the field of low voltage high current application such as 12V voltage regulator for microprocessors.

Patent Information: