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My switching power supply (mc34063) makes audible noise

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Psi:
Can you post a scope pic of the VCC pin, just want to check if your input is stable.

sarfata:
Great idea, thanks. I am using a linear lab power supply (mastech hy3003d) by the way.

This is the result:



There is indeed 1v spikes in the input but this seems to be related to the load (my board and its power supply) because if I just put a resistor (taking much more current) on the output of my power supply I dont see any ripple that big.

amyk:
You mention you were powering an ATMega with your SMPS, so is there anything that occurs at ~2.2KHz intervals on it? Have you tried a plain resistive load to see if the spikes go away? Also consider adding another choke at the output --- a few tens of uH should be sufficient. You can learn a bit from looking at PC PSU schematics.

T4P:
A resistive load makes the spikes go away, he mentioned

dan.corneanu:
I know this is a very old topic, but was there any resolution on this issue?
I am also seeing the same level of noise on the input and it is not from the powersource bacause with a resistive load it is clean.

Regards,
Dan

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