Other Parts Discussed in Thread: BQ2000
Hi
Vtech engineer just refer to ref. circuit inside your datasheet to do the change for 6 cells NiMH 7.2V 4000mAh battery charging.
1) Change R6 from 210kohms to 500kohms ( 2pcs 1Mohms in-parallel ) and R7 from 105kohms to 100kohms to get 6 : 1 ratio from 6 cells battery for BAT pin.
2) Fine tune R3 to get 1.5A charging current.
3) Change R8 from 6.81kohms to 33kohms for limit the maximum charging time.
4) Power supply voltage is DC12V.
Refer to your ref. circuit, a 5V1 zener diode is used to regulated a 9V to 16V charging source to around 5V for all pins of the charging IC.
they want to clarify clearly from you. Is it mean if below rules can be fulfilled, TI BQ24401 charging IC can still work safe for 6 cells NiMH battery charging ?Is it still safe if we fine tune voltage divider to 6 : 1 for 6 cells battery pack charging ? If not, would you please explain why ?
a) Keep VCC and all pins voltage within DC4V to 6V.
b) Change voltage divider ratio to 6 : 1 for BAT pin from battery voltage.
c) All components inside this circuit have enough power rating margin and enough heat sink.
