Hello All,

I have a project that requires that a PIC be run from batteries. However I have a few questions, I have been unable to find any information from the Microchip website, which is quite surprising.

1) Assuming I use NiCad of NiMH batteries with a cell voltage of 1.2v, should I use 4 (4.8v) or 5 (6.v), bearing in mind the discharge slopes of each. I would imagine 6 would be my best bet,

2) As this is a low discharges application, is NiCad or NiMH the most suitable, or something else?

3) Should any regulation be used? This is unlikely I know, as batteries make very nice power supplies, but nevertheless, any thoughts? Battery life is important, and any form of regulation will draw extra current,

4) When the batteries start to go flat, the PIC will stop working(!), most likely it will malfunction. How should I protect from this? I have considered using a modified brown out protection circuit, which disables a latch controlling the power. It is importants that the batteries are not allowed to recover (if indeed they would at low discharge rates) and start up the PIC.

Basically I am asking for advice from your experience. Am I on the right track? Any ideas, pointers to resources would be very welcome.

Regards,

Stuart.

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Stuart Allen                         Tel   : +49 (0)711 5858-501
Development Engineer                 Fax   : +49 (0)711 5858-199
Sony Stuttgart Technology Center

Stuttgarter Strasse 106
D-70736 Fellbach, Germany
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