Hi team,
Can the team help review the schematic of BQ25703?
Vin=12V
Battery pack:
3S3P
Charging voltage:12.6V
Charging current: 2A
Cut off voltage:9V
Max discharging current:3A
another question is about the min system voltage and how to set it.
9.5V? sys votlage will use converter boost to 18V. BQ25703 sch.pdf
Jimmy,
I reviewed the schematic. Overall it looks OK. Some notes and items to fix below:
1. I see 330uF POSCAP on VIN and VSYS, recommend to also add Ceramic caps for high frequency voltage ripple. Usually we recommend 33uF POSCAP and 4x10uF MLCC Caps + 2 DNP.
2. Voltage divider for CELL_BATPRESZ should target 55% of VDDA for 3S, currently ~65%. Remove R454 and R457, keep R464 (100K) and R456 (64.9K) for 3S
3. ILIM_HIZ voltage divider missing lower resistor (only see 383K pullup to VDDA), needs to be set based on planned ILIM setting:
Regarding MinSystemVoltage:
- The minimum system voltage is set by REG0x0D/0C().
- To set the minimum system voltage, write a 16-bit MinSystemVoltage register command (REG0x0D/0C()) using the data format listed in Table 27 and Table 28. The charger provides minimum system voltage range from 1.024V to 16.128 V, with 256-mV step resolution. Any write below 1.024 V or above 16.128 V is ignored. Upon POR, the MinSystemVoltage register is 3.584 V for 1 S, 6.144 V for 2 S and 9.216 V for 3 S, and 12.288 V for 4 S.
Thanks,
Khalid
