STBC21 Datasheet, PDF (1/54 Pages) STMicroelectronics – LI+ battery charger with thermal regulation

STBC21
LI+ battery charger with thermal regulation
Datasheet − production data
Features
■ Programmable charge current up to 1.1 A
■ Floating voltage limitation outside the safety
temperature range
■ PSE fully compatible
■ Low battery voltage detection for pre-charge
setting
■ Automatic recharge
■ Two charge status output pins
■ Constant current / constant voltage operation
■ No external MOSFET, sense resistors or
blocking diode required
■ Reverse current blocking (50 µA max.)
■ Short-circuit protection and thermal shutdown
■ Less than 1 mA supply current in standby
mode
■ Reversed battery polarity protection
■ I²C interface for charging parameters
programming
■ ESD: HBM ± 2 kV, CDM 500 V on every pin
■ HTSSOP-14 (5 x 4.4 mm) package available
■ -25 °C to 125 °C operative junction
temperature
Description
The STBC21 is a constant current/constant
voltage charger for single cell Li-Ion batteries.
Most of the charging parameters, including
floating voltage, pre-charge and termination
current are programmable in NVM memory. While
fast charging current is programmed using an
external resistor. The constant current process is
split into three phases depending on the battery
voltage. If the battery voltage is below 3.0 V, the
charging current is set to a programmable value
below 200 mA. A timeout of 60 minutes is used in
this phase to detect faulty batteries. When the
battery voltage goes above 3.0 V, the charger
HTSSOP-14 (5 x 4.4 mm)
moves to the fast-charge procedure with a current
programmable by an external resistor up to 1.1 A.
When the battery reaches the value of the floating
voltage the charger enters “constant voltage”
mode. Even in this mode a protection timer is
active to avoid risks due to damaged batteries.
The charge cycle is automatically terminated
when the current flowing to the battery reaches
the value programmed in NVM. There is also a
programmable lag time after the termination to
maximize the battery charge. An internal block
regulates the battery floating voltage when its
temperature is outside the safety range between
10 °C and 45 °C, (JEITA/PSE regulation). The
floating voltage inside the safety range is set, by
default, at 4.2 V. If the external power supply is
removed, the STBC21 turns off and a 50 µA
(max.) current can flow from the battery to the
device. The device also has an undervoltage
lockout and automatic recharge capability which
can be enabled/disabled by setting a bit in NVM.
Two separate status pins allow a lot of information
to be gotten based also on flashing frequency and
duty cycle. The STBC21 also includes a reversed
battery polarity protection to prevent damage due
to incorrect battery insertion. The package is a
HTSSOP-14 (5 x 4.4).
Table 1. Device summary
Order code
Package
STBC21FTR
HTSSOP-14
Packaging
Tape and reel
June 2012
This is information on a product in full production.
Doc ID 023256 Rev 1
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