tps65951 donot charge the BKBAT when power off.

bcb9 bcb9

Other Parts Discussed in Thread: AM3715, TPS65951

I use am3715 and tps65951 on my board. I connect a supercap to BKBAT pin of tps65951 as backup battery.When system power on, I set the BBCHEN bit to 1, the supercap can be charged correctly.But when I power off the system(the main battery is still present),I find that tps65951 do not charge the supercap anyway. When re-power on the system, I can read the value of BBCHEN bit is 0. How to charge the supercap continue when system power off?

over 10 years ago

0 AlainC over 10 years ago

TI__Intellectual 1915 points

Hi, this register BB_CFG is located in VRRTC domain which is reset when device is powered off therefore BBCHEN bit is cleared; there is no possibility to maintain the backup battery charger on in this case.

Best regards, Alain.

0 bcb9 bcb9 over 10 years ago in reply to AlainC

Prodigy 140 points

Thank your reply! The behavior of backup battery on tps65951 is different as normal. I cannot understand why tps65951 can be designed like this.

Power management

Power management forum

tps65951 donot charge the BKBAT when power off.