Multifunction Power Supply

Many embedded systems these days need +5V power supply with some special functions such as power-fail detection, zero-crossing signals for mains power supply and possibility to maintain the charging of built-in batteries. -- Petre tzv Petrov


An actual-size, single-side PCB for the multifunction power supply is shown in Fig. 2 and its component layout in Fig. 3. After assembling the circuit on a PCB, enclose it in a suitable case. Fix all the connectors at the rear side of the cabinet for connecting the mains and taking the outputs.

To test the circuit, switch on switch S1 and check various voltages as indicated in the test-points table. LED1 indicates the availability of 5V.

EFY note. Care must be taken while handling the high-voltage section of power transformer X1 as it is connected to the mains power supply.

The author has worked as a researcher and assistant professor in Technical University of Sofia (Bulgaria) and as a lecturer in Kingdom of Morocco. Now he is an electronics engineer in the private sector in Bulgaria


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