bq24700, bq24701

NOTEBOOK PC BATTERY CHARGE CONTROLLER

AND SELECTOR WITH DPM

SLUS452B – APRIL 2001 – REVISED NOVEMBER 2002

18

POST OFFICE BOX 655303

APPLICATION INFORMATION

UDG–00116

(a) VBATSET < 0.25 V

(b) VBATSET > 0.25 V

13

10

+

9

1.25 V

0.25 V

BATSET

BATP

R2

VBAT

gm AMPLIFIER

1.25 V

R1

VREF = 5 V

COMP

13

10

+

9

1.25 V

0.25 V

BATSET

BATP

VBAT

gm AMPLIFIER

1.25 V

COMP

Figure 6. Battery Error Amplifier Input Multiplexing Scheme

programming the battery charge current

The battery charge current is programmed via a voltage on the SRSET pin. This voltage can be derived from

a resistor divider from the 5-V VREF or by means of an DAC. The voltage is converted to a current source that