光耦设计裕度的计算Calculation of Design Margin for CTR of Optocouplers. Author: Kevin Wildash Last updated: 01 Sept 1998 File: ctr1.doc 1. Introduction: Optocouplers are used in switchmode power supply units (PSU) to isolate signals which cross the primary to secondary isolation boundary. Typical uses are in the feedback and shutdown circuits. Such circuits are critical to the correct operation of the PSU and for the protection of the customer's equipment. Since the performance of an optocoupler degrades with age, it is not sufficient to assume that if a PSU is working today that it will therefore be working correctly tomorrow. A calculation of the predicted performance is necessary. This paper details a procedure which will allow the eng……