STBC08 Datasheet, PDF (11/17 Pages) STMicroelectronics – 800mA Standalone linear Li-Ion Battery charger with thermal regulation

STBC08
Application information
-00 is Precharge Mode (Trickle charge mode) or Charge Mode. V_CC is higher than V_UVLO
and R_PROG is connected to the PROG pin.
- 01 is STANBY MODE (charge completed) or SHUTDOWN MODE (R_PROG not connected).
- 11 supply is not sufficient.
6.5
PROG pin
Charge Current Program, Charge Current Monitor and Shutdown Pin. The charge current is
programmed by connecting a 1% resistor, R_PROG, to ground. When the device is charging in
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:
I_BAT = (V_PROG/R_PROG)*1000
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
The R_PROG resistor is used to set the charge current value. The battery charge current is
1000 times the Prog pin current value. The program resistor and the charge current are
calculated using the following formula:
R_PROG=1000*V_PROG/I_BAT;
The charge current out of the BAT pin can be monitored through the PROG pin voltage
using the following equation:
I_BAT=(V_PROG/R_PROG)x1000
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
the V_O with the reference.
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
voltage falls below 100mV for longer time than t_TERM (~1ms). The charge current is latched
off, the device enters in standby mode and the input supply current drops to 200µA.
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