Electronic – What kind of power supply filter is this

coildiodesfilterpower supply

I found this filter in an inherited design. It is supposed to filter some noisy input (around 13V) coming from a generator.

I'm new to designing filters and coils but something feels off here – I kind of expected a resistor for a low-pass. Is this some kind of standard filter against voltage spikes? I did not find any documentation for this.

The reason I'm asking is that recently I got a board back where D1 was burnt and I'm looking for ways to improve this.


Best Answer

D1 in that circuit is a Transient Voltage Suppressor, this is designed to protect other devices attached between VCC and GND from short term over voltage events. It doesn't really provide any filtering from noise though.

If it burned that suggests it was subjected to a longer lasting period of over voltage than it was able to handle.