tps65910

6.6 Backup Battery Management

The device includes a back-up battery switch connecting the VRTC regulator input to a main battery

(VCC7) or to a back-up battery (VBACKUP), depending on the batteries voltage value.

The VRTC supply can then be maintained during a BACKUP state as far as the input voltage is high

enough (>VBNPR threshold). Below the VBNPR voltage threshold the digital core of the device is set

under reset by internal signal POR (Power-on Reset).

The back-up domain functions which are always supplied from VRTC comprehend:

• The internal 32-kHz oscillator

• Backup registers

The back-up battery can be charged from the main battery through an embedded charger. The back-up

battery charge voltage and enable is controlled through BBCH_REG register programming. This register

content is maintained during the device Backup state.

Hence enabled the back-up battery charge is maintained as far as the main battery voltage is higher than

the VMBLO threshold and the back-up battery voltage.