STBC08

Application information

11/17

- 11 supply is not sufficient.

6.5

PROG pin

Charge Current Program, Charge Current Monitor and Shutdown Pin. The charge current is

constant current, the value of voltage on this pin is 1.0V. In other conditions, the voltage on

this pin can be used to measure the charge current using the following formula:

The PROG pin is used to shut down the device, disconnecting the program resistor from

ground a 1µA current flows to pull the PROG pin high. If the value of this Pin is 1.21V

(shutdown threshold voltage), the device enters Shutdown mode and the input supply

current drops to 25µA. Driving this pin to voltage beyond 2.4V a current of 35µA flows into

the device from PROG pin.

6.6

Programming charge current

1000 times the Prog pin current value. The program resistor and the charge current are

calculated using the following formula:

The charge current out of the BAT pin can be monitored through the PROG pin voltage

using the following equation:

6.7

BAT pin

Charge Current Output pin. It provides charge current to the battery and regulates the final

float voltage to 4.2V. An internal precision resistor is used as a feedback loop to compare

6.8

Charge termination

A charge cycle is terminated when the final float voltage is reached consequently the charge

current falls to 1/10th of the programmed value. The charge is over when the PROG pin

off, the device enters in standby mode and the input supply current drops to 200µA.