Apple Inc.
High Performance Synchronous Rectification in Discontinuous Current Mode Converters

Abstract:

Disclosed herein are synchronous rectifier control techniques for Discontinuous Current Mode (DCM) converters. These techniques may be particularly advantageous where the current shape is triangular in nature with a fixed down-slope. Such converters may include DCM flyback converters and DCM buck converters. The proposed control techniques can reduce body diode conduction of the synchronous rectifier and optimize turn-off timing, while negating the effect of parasitic circuit elements. These techniques may also help simplify the control of synchronous rectifiers operated in parallel mode. Finally, such techniques may also help achieve higher performance in variable output voltage converters and converters that operate at high switching frequencies.