BQ24150A Datasheet, PDF (19/41 Pages) Texas Instruments – Fully Integrated Switch-Mode One-Cell Li-Ion Charger With Full USB Compliance and USB-OTG Support

bq24150A
bq24151A
www.ti.com ..................................................................................................................................................................................................... SLUS931 – APRIL 2009
battery voltage is still above recharge threshold, the battery is present and the charge done is detected.
However, if the battery voltage is below battery recharge threshold, the battery is absent. Under this condition,
the charge parameters (such as input current limit) are reset to the default values and charge resumes after a
delay of T_INT, as shown in Figure 23. This function ensures that the charge parameters are reset whenever the
battery is replaced.
Battery Detection at Power Up
The bq24150A has a unique battery detection scheme during the start up of the charger. At VBUS power up, if
the timer is in 32-minute mode, the bq24150A starts a 32ms timer when exiting from short circuit mode to PWM
charge mode. If the battery voltage is charged to recharge threshold (V_(OREG) – V_(RCH)) and the 32ms timer is not
expired yet, the bq2150A determines that the battery is not present; then stops charging and immediately goes to
the high impedance mode. However, if the 32ms timer is expired when the recharge threshold is reached, the
charging process continues as in the normal battery charging process.
Battery Short Protection
During the normal charging process, if the battery voltage is lower than the short-circuit threshold, V_(SHORT), the
charger operates in linear charge mode with a lower charge rate of I_(SHORT), as shown in Figure 22.
Charge Status Output, STAT Pin
The STAT pin is used to indicate operation conditions for bq24150A/1A. STAT is pulled low during charging and
EN_STAT bit in control register (00H) is set to "1". Under other conditions, the STAT pin acts as a high
impedance (open-drain) output. Under fault conditions, a 128-µs pulse is sent out to notify the host. The status of
STAT pin at different operation conditions is summarized in Table 1. The STAT pin can be used to drive an LED
or communicate to the host processor.
Table 1. STAT Pin Summary
CHARGE STATE
Charge in progress and EN_STAT=1
Other normal conditions
Charge mode faults: Timer fault, sleep mode, VBUS or battery
overvoltage, poor input source, VBUS UVLO, no battery,
thermal shutdown
Boost mode faults: Timer fault, over load, VBUS or battery
overvoltage, low battery voltage, thermal shutdown
STAT
Low
Open-drain
128-µs pulse, then open-drain
128-µs pulse, then open-drain
Control Bits in Charge Mode
CE Bit (Charge Mode)
The bit of CE in control register is used to disable or enable the charge process. A low logic level (0) on this bit
enables the charge and a high logic level (1) disables the charge.
RESET Bit
The bit of RESET in control register is used to reset all the charge parameters. Writing '1" to RESET bit resets all
the charge parameters to default values and RESET bit is automatically cleared to zero once the charge
parameters are reset. It is designed for charge parameter reset before charge starts, and it is not recommended
to set the RESET bit when charging or boosting in progress.
OPA_Mode Bit
OPA_MODE is the operation mode control bit. When OPA_MODE = 0, the bq24150A/1A will go to the charge
related operation modes if HZ_MODE is set to "0", refer to Table 2 for detail.
Copyright © 2009, Texas Instruments Incorporated
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