The design requirements include the following:
- Input supply up to 18 V
- Battery is 4-cell NiMH
- Fast charge current:
ICHG = 30 mA
- Recharge voltage for intermittent
cycles: VRECHG = 1.33V x 4 = 5.32 V
- Charge safety timer:
tSAFETY: 16 hr
- TS – Battery temperature sense =
10-kΩ NTC (103AT-2)
- RS = 1.9 kΩ
and RP = 400 kΩ added to modify battery charging temperature
window to: 0ºC to 60ºC
- CE is a
control pin, pull high to disable the charger