Repair Voltage Regulator Control Circuit in Power Supply PCB Card system, both the direct error sampling circuit and the indirect error sampling circuit belong to the voltage regulator control circuit, but there are differences in the error sampling method.
Among them, by installing a sampling winding on the switching transformer, then a voltage can be obtained after rectification and filtering. This voltage is proportional to the output voltage. The voltage is changed by this effect, and then the control switch is connected by the voltage communicate with disconnection and finally achieve the role of voltage stabilization.
This kind of voltage stabilization control circuit is called indirect error sampling. The potentiometer and filter capacitor of this kind of power source belong to the position where it is easy to fail. When handling, you need to pay attention to the subsequent inspection after connecting the dummy load.
Switching power supply output voltage sampling circuit using direct sampling is called direct error sampling. Direct error sampling circuit usually has the switching power supply primary isolation element, switching power supply secondary isolation element, the specific is the photocoupler, and this Components are also prone to medical instrument circuit board failure troubleshooting. Locally, when a fault occurs, the voltage at the output will show a clear upward trend.
