how to design a battery back up for ARM7

[s3034585]

coin cell battery circuit design

Hi Guys,

I am trying to design a rechargable coin cell battery backup circuit for VBAT in ARM LPC2378. I googled for similar circuit or design guidlines but didnt get much help.

Can some one please explain how to design a circuit to provide coin cell battery backup with recharging for the coin cell. I am also considering using a super cap as alternative for battery.


Thanks in advance
tama

 

[kender]

battery backup circuit

Hi Tama,

If it's just a coin cell, I would try a simple approach - connect the battery to 3.3V through Schottky diode in series with a current-limiting resistor. A similar approach is shown in the datasheet for my favorite RTC chip (figure 6 here **broken link removed**).

- Nick