STBC03 Datasheet, PDF (18/34 Pages) STMicroelectronics – Li-Ion linear battery charger with LDO and load switches

Functional pin description
STBC03
6
6.1
6.2
6.3
Functional pin description
GND, AGND
The STBC03 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 being discharged. 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 650 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 the 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, BATMS_EN
Battery voltage measurement. If BATMS_EN is high, the 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. To minimize overall system power
consumption, this function must be disabled. BATMS_EN pin should be pulled low.
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