How to generate -3.3V and -5.2V from either 12V, -12V or +5V

Thread Starter

matthej

Joined Oct 10, 2020
35
Hi,
I need to generate -3.3V and -5.2V on my board. Power for -3.3V is 1.4W and -5.2V is 9.3W.

I have + 12V, -12V and +5V coming from the power board.

I am unfamiliar with generating these negative voltages. Does anyone have an idea on how to do this?
Inverting buck-boost converter?

Thanks!
 

dl324

Joined Mar 30, 2015
12,678
Inverting buck-boost converter?
You could use inverting regulators from your positive supplies or linear regulators from your -12V supply (if it has sufficient capacity).

My go to for switching regulators is MC34063A. They're readily salvaged from a lot of devices.
 

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crutschow

Joined Mar 14, 2008
26,740
The switching regulators would be a lot more efficient.
Linear regulators would dissipate 3.7W to generate -3.3V, and 12.2W to generate -5.2V from the -12V for your power requirements.
If you don't want to roll your own, you could likely buy some inexpensive modules from Amazon or Ebay.
 
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