STBC02 Datasheet, PDF (19/39 Pages) STMicroelectronics – Automatic power path management

STBC02
Functional pin description
6
6.1
6.2
6.3
Functional pin description
GND, AGND
The STBC02 ground pins.
NTC
The battery temperature monitoring pin. Connect the battery NTC thermistor to this pin.
The charging cycle stops when the battery temperature is outside of the safe temperature
range (0 °C to 45 °C). When the charging cycle is completed, the NTC pin goes to a high
impedance state, therefore the NTC thermistor can be also used, together with an external
circuitry, to monitor the battery temperature while it is discharging. If the NTC thermistor is
not used, a 10 kΩ resistor must be connected to ensure proper IC operations.
ISET and IPRE
Fast and pre-charge current programming pins. Connect two resistors (RISET, RIPRE) to
ground to set the fast and pre-charge current (IFAST, IPRE) according to the following
equation (valid for IFAST, IPRE > 5 mA):
Equation 1:
𝐼_{𝑃𝑅𝐸}
=
𝑉_{𝐼𝑃𝑅𝐸}
𝑅_{𝐼𝑃𝑅𝐸}
∗
𝐾; 𝐼_{𝐹𝐴𝑆𝑇}
=
𝑉_{𝐼𝑆𝐸𝑇}
𝑅_{𝐼𝑆𝐸𝑇}
∗ 𝐾
Where VISET = VIPRE = 1 V and K = 200. Fast charge and pre-charge currents can be
independently set from 1 mA to 450 mA. End-of-charge current value is typically 5% of the
fast charging current value being set.
For low charging current (IFAST, IPRE < 5 mA), the RISET and RIPRE values in following table
must be used.
IFAST, IPRE
Table 6: Charging current setting
RISET, RIPRE
5 mA
40.5 k
2 mA
110 k
1 mA
260 k
Both RISET and RIPRE must be always used. Short-circuit to ground or open circuit are not
allowed options.
6.4
BATMS
Battery voltage measurement. BATMS pin is internally shorted to the BATSNS pin during
normal conditions to monitor the battery voltage using external components (µC and
embedded ADC). The internal path from BATMS pin to the battery is opened in case any of
the following conditions occur: overcurrent, battery over-discharge, shutdown mode, short-
circuit on SYS or LDO. This function can be enabled / disabled by SWIRE. To minimize
overall system power consumption, this function must be disabled.
DocID029261 Rev 2
19/39