光耦设计裕度的计算 Optocouplers are used in switchmode power supply units (PSU) to isolate signals which cross theprimary 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'sequipment. Since the performance of an optocoupler degrades with age, it is not sufficient to assumethat if a PSU is working today that it will therefore be working correctly tomorrow. A calculation of thepredicted performance is necessary.