Synchronous rectification with adaptive timing control

This paper describes a MOSFET synchronous rectifier suitable for use in high-frequency DC-DC converters. The MOSFET control circuitry is designed to replicate the basic functionality of a rectifier diode, turning on when the voltage across the device falls to zero, and turning off when the current through the device tries to reverse. This synchronous rectification device can be incorporated into a wide range of converter topologies, without the restrictions imposed on other synchronous rectification schemes. In order to minimize the losses resulting from gate drive timing errors at high switching frequencies (~1 MHz), adaptive timing control loops are used to null the inherent delays of the control and driver circuitry. The power FETs and control circuitry are integrated in a 1.2 μm CMOS process