MCF52233CAF60 and monitoring my power supplies

[rlstraney]

Hello,

I have two +5 volt power supplies in my product.  One is used as a redundant supply so only one is active at a time.  I want to report to the user via my command line the status of the power supplies.   

I really only need to report if they are "up" - not necessarily their exact voltages.  

Can anyone share how this is generally done? 

Here are my first ideas:

Use 2 voltage supervisors to monitor each supply and run their outputs to my 52233 and just read the pins for the correct logic level. 

I also thought of running the voltages from the supplies over to the processors A/D inputs (Via a voltage divider since it appears the 52233 can read up to Vrefh which cannot exceed VDDA.) and sampling them.

Or are there other ways to accomplish this? 

Thanks

Renee

[admin]

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rlstraney wrote:

Or are there other ways to accomplish this?
 

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You could simply connect them to digital inputs using suitable voltage dividers. Information on digital input switching threshold levels should be in the datasheet.

If you want a more or less precise comparator, have a look at TL431A. It's extremely cheap and should be good for this job.