Multiple output DC power supply - has one regulated voltage output and other outputs voltage limited by passive components

摘要

The application is to d.c. power supplies with at least two output voltages regulated by controlling the input to the d.c. converter. One output voltage is closely regulated, the other output is thus partly regulated, and is protected against overvoltage, e.g. due to loss of load, by a static element. The regulator (4) measures the controlled output voltage (Ua1) and adjusts the transistor chopper (2) on the d.c. input to the converter transformer (3) to an appropriate mark to space ratio. As the second output voltage (Ua2) is connected to a winding on the same transformer it is loosely regulated in accordance with the load (9) on the controlled section. To guard against overvoltages the second section (Ua2) is fitted with a Zener diode (10) and oppositely poled diode (11). If the Zener is conducting due to h.v. the spill current tends to flow in the load (9) of the controlled circuit. If this load is insufficient the voltage rises and the regulator (4) acts to correct the condition.