Design procedure for a photo-coupler type error amplifier in a DC-DC converter

摘要

A voltaic isolated error-amplifier using a photo-coupler and a shunt-regulator is widely used as a part of a feedback controller in a Dc-Dc converter. The design of this error-amplifier is usually based on the trials and errors, and the exact formulation of its characteristics has not been reported before. This paper presents analytical circuit models of the photo-coupler and the shunt-regulator, and discusses the design procedure of the error-amplifier.