STBCFG01 Datasheet, PDF (19/37 Pages) STMicroelectronics – Integrated current sensing resistor

STBCFG01
Operation description
The device also features an output overvoltage protection which turns off OTG boost if the
output voltage rises above VBUSOVP. If the overvoltage lasts for more than tVBUSOVP, OTG
boost is disabled and an alarm is generated.
Together with the standard cycle-by-cycle current limit for the inductor peak current, the
STBCFG01 also implements an average battery current limitation to avoid excessive
battery voltage drop during peaks in system current consumption. When the average boost
input current reaches the programmed limit (IBATLIM = 350 mA, 450 mA, 550 mA, 950 mA),
OTG boost is disabled and an alarm is generated.
5.3
LDO regulator
The STBCFG01 integrates a 4.85 V, 50 mA LDO regulator which is active when DCIN
voltage is higher than VINMIN and lower then VINMAX. LDO is also active when the battery is
not connected and in OTG mode, while it is turned off in automatic shutdown conditions
(VDCIN - VCELL+ < VASD). LDO function can be disabled through I²C and its output is
protected against short-circuit.
5.4
Pre-bias
In order to allow proper functionality with input sources not integrating the necessary
minimum load to provide a valid voltage, the STBCFG01 integrates an automatic pre-bias
circuit: if the input voltage (VDCIN) is above the input OVP threshold but lower than the pre-
bias OVP threshold (VINOVP < VDCIN < VINOVP_PB) a pre-bias current is applied to DCIN to
attempt reducing the input voltage down to a valid level. During the charging cycle, if the
pre-bias current has been activated, it is kept on only during trickle charge and taper
charge. The pre-bias current is also turned off in automatic shutdown conditions (ASD).
The pre-bias current is active only if the input voltage is in the activation range for at least
tPBD (5 ms typ.). The pre-bias function can be disabled through I²C.
Figure 8: Pre-bias enable strategy
DocID026474 Rev 3
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