STBC08 Datasheet, PDF (10/17 Pages) STMicroelectronics – 800mA Standalone linear Li-Ion Battery charger with thermal regulation

Application information
6
Application information
STBC08
The STBC08 uses an internal P-Channel MOSFET to work in constant current and constant
voltage method. It is able to provide up to 800mA with a final regulated output voltage of
4.2V ± 1% in full temperature range. No blocking diode and sensing resistor are required. It
is also possible to use an USB port as power supply voltage.
6.1
Charge cycle
A charge cycle begins when the voltage at the V_CC pin rises above the UVLO threshold
level, the R_PROG program resistor of 1% is connected between the PROG pin to GND pin
and when a battery is connected to the charger output. If the battery voltage is below 2.9V,
the charger enters Trickle Charge mode. In this condition, the device supplies 1/10 of the
programmed charge current to bring the battery voltage up to safe level otherwise the life of
a battery is reduced. If the BAT pin voltage is higher than 2.9V the charger enters in
Constant Current Mode. When the BAT pin voltage is close to the final float voltage (4.2V)
the device enters in Constant Voltage Mode and the charge current begins to decrease. The
charge cycle is terminated when the current drops to 1/10 of the programmed value.
6.2
V_CC Pin
Input Supply Voltage. This pin is used to supplie the device in the range from 4.25V to 6.5V
voltage. A bypass capacitor of 1µF is recommended for use. When V_CC value drops of
30mV of the BAT pin voltage, the device enters in Shutdown Mode, dropping I_BAT to less
than 2µA.
6.3
Power ON pin
The POWER ON pin is an open drain flag that indicates V_CC presence, V_UVLO<V_CC<7.2V
and V_CC>V_BAT. While in high impedance indicates that V_CC< V_UVLO, V_CC>7.2V or
V_CC<V_BAT. In high impedance status the V_CC is insufficient to start the charge cycle.
6.4
CHRG pin
The CHRG pin is an open drain flag, it indicates the status of the charge. When the pin is in
low state, the device is charging the battery. If the pin is in high impedance state the charge
is terminated.
Table 5. CHRG
Power-ON
LOW
HIGH
LOW
00
-
Table 5 describes Flag Status values for the CHRG pin.
CHRG
HIGH
01
11
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