Switch controller for protecting against damaging after-effects from component faults has a switch controller with a transformer, a switch transistor to control primary peak current, a safety cutout resistor and a primary winding

摘要

A switch controller has a transformer (T100). A switch transistor (V132) uses the transformer to control a primary peak current. Switch/control elements switch the switch transistor on and off periodically. A primary circuit is made up of the switch transistor, a safety cutout resistor (R125) and a primary winding for the transformer. Linked to the safety cutout resistor, a control transistor (V138) is driven by a voltage drop on the safety cutout resistor.