Other Parts Discussed in Thread: TPS61220, CC2530
Hello,
I have designed a battery powered device using cc2530 module. The batteries will be two alkalines batteries. Besides, in order to get a better effectiveness from them I decided to use a TPS61220 step up converter following by the TPS71733 LDO, achieving a 3.3 output power supply.
Nowadays I am thinking of monitoring the battery life by measuring the battery voltage. I mean, what I would like is my device warns when their batteries are running out of charge. To that end, I have thought of sampling the voltage signal from the batteries output directly using the cc2530's ADC. When I said directly,I mean that I don't intend to sample the power supply at the output of the TPS71733, but at the output of the batteries what's at the input of the TPS61220.
At this point, I notice I can bump into two kinds of troubles:
First, the cc2530's ADC was already being used. However, I think I can monitor to sample from both different channels at different times. Then, it shouldn't be a matter, but just in case, I would like to have a feedback to know if there is any problem I am forgetting, or, how effective will be using the ADC while it samples from different analog channels, although not at the same time.
Secondly, my doubt is related with the maximum input voltage the ADC can support. From the datasheet, this value is the supply voltage, in my case that's 3.3V. However if the batteries are series associated, their whole voltage could be higher than the maximum input ADC. What will happen in that case? What if an input channel of the ADC has a signal above the voltage allowed? I assume it is going to work badly, but Is there any chance to be damaged? If so, I will have to assciate the batteries in parallel.
I hope to hearing from you soon!
Thank you very much in advance,
Lucía
