Hello,
I read the datasheet and reference manual of BQ76952 and i think i understood how TS2 works to wake up. But my requirement is not just wake up the BMS, but also to know what source waked up the BMS,. For example, i have 3 possible sources to wake up BQ76952 from Sleep: Fuel Gauge Button on Battery, Charger circuit, Load Circuit. So i came up with a simple circuit for TS2 that helps my HOST MCU record what source woke up the BMS. Please see below picture.
I would like to implement following:
1) Put BQ76952 to Shutdown mode by sending a SHUTDOWN() command.
2) There are 3 different circuits/switches that can wake up the BQ76952 from shutdown. See below circuit.
3) When Any one of the switch is pressed, BQ wakes up from Sleep. All three resistors are chosen and still keeps the Voltage at TS2 pin below 0.7V when a button is pressed.
4) TS2 Config register (Table 13-10 in reference manual) is configured as Thermistor input, set to 18K pill up for thermistor measurement and OPT[1:0] set to 10 ( thermistor temperature measurement, reported but not used for protections). So when BQ chip wakes up from any one Switch in the schematic, BQ exits shutdown and starts measuring the TS2 as temperature.
5) My Host MCU can read the TS2 temperature and figure out what source waked up the BMS and remain in this state until, my MCU puts BQ in shutdown mode again.
Is this the right approach and does it work? Any other better suggestions would he helpful and welcomed.
Thanks,
Naga Penmetsa
