battery backup switchover ic

Hello,

I am trying to decide on a battery switchover IC. I see that there are many options.

I am running a PIC24 micro and need to be able to retain data in the RTCC in deep sleep mode once the main battery is too low for the processor to run. I will l have a battery backup (CR2032) to run the Micro in the sleep mode low power mode.

I am wondering what you guys are using for your applications. All I need is an IC that sends an interrupt to alert the that a battery switchover has occurred.

I see that maxim has a pretty good line of ic's that run with a low backup current. It appears that I will need one with a batt-on output to let me know when the switchover has occurred.

Do you recommend other vendors for this kind of function?

Do you need a separate IC? You can connect your 3v cell via a schottky diode, that will give you plenty of power for ram retention during "deep sleep".

Now since your sleep modes comes when the battery is very low, surely your PIC24 is monitoring battery voltage? So then the PIC detects battery is lower than X volts just put it into sleep. Job done, total parts needed; 1 schottky diode.

I'm doing similar thing what RB suggested.

Hi,
To report the switch over action, a simple comparator should do the job. All you have to do is set the comparator threshold to a level that you choose for switch over. Once the threshold level is crossed, the comparator's output will assert and signal the microcontroller that the switch over action has taken place.