BQ25600 Datasheet, PDF (31/66 Pages) Texas Instruments – I2C Controlled 3.0-A, Single Cell Battery Charger With up-to 40-V Overvoltage Protection Controller for High-Input Voltage and Narrow Voltage DC (NVDC) Power Path Management

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bq25600, bq25600D
SLUSCJ4 – JUNE 2017
7.3.10.3 Thermal Regulation and Thermal Shutdown
7.3.10.3.1 Thermal Protection in Buck Mode
The bq25600 and bq25600D monitors the internal junction temperature T_J to avoid overheat the chip and limits
the IC surface temperature in buck mode. When the internal junction temperature exceeds thermal regulation
limit (110°C), the device lowers down the charge current. During thermal regulation, the actual charging current is
usually below the programmed battery charging current. Therefore, termination is disabled, the safety timer runs
at half the clock rate, and the status register THERM_STAT bit goes high.
Additionally, the device has thermal shutdown to turn off the converter and BATFET when IC surface
temperature exceeds T_SHUT(160ºC). The fault register CHRG_FAULT is set to 1 and an INT is asserted to the
host. The BATFET and converter is enabled to recover when IC temperature is T_{SHUT_HYS} (30ºC) below
T_SHUT(160ºC).
7.3.10.3.2 Thermal Protection in Boost Mode
The device monitors the internal junction temperature to provide thermal shutdown during boost mode. When IC
junction temperature exceeds T_SHUT (160ºC), the boost mode is disabled by setting OTG_CONFIG bit low and
BATFET is turned off. When IC junction temperature is below T_SHUT(160ºC) - T_{SHUT_HYS} (30ºC), the BATFET is
enabled automatically to allow system to restore and the host can re-enable OTG_CONFIG bit to recover.
7.3.10.4 Battery Protection
7.3.10.4.1 Battery overvoltage Protection (BATOVP)
The battery overvoltage limit is clamped at 4% above the battery regulation voltage. When battery over voltage
occurs, the charger device immediately disables charging. The fault register BAT_FAULT bit goes high and an
INT is asserted to the host.
7.3.10.4.2 Battery Over-Discharge Protection
When battery is discharged below V_{BAT_DPL_FALL}, the BATFET is turned off to protect battery from over discharge.
To recover from over-discharge latch-off, an input source plug-in is required at VBUS. The battery is charged
with I_SHORT (typically 100 mA) current when the VBAT < VSHORT, or precharge current as set in IPRECHG
register when the battery voltage is between V_SHORTZ and V_{BAT_LOWV}.
7.3.10.4.3 System Over-Current Protection
When the system is shorted or significantly overloaded (IBAT > IBATOP) and the current exceeds BATFET
overcurrent limit, the BATFET latches off. Section BATFET Enable (Exit Shipping Mode) can reset the latch-off
condition and turn on BATFET.
7.3.11 Serial interface
The device uses I²C compatible interface for flexible charging parameter programming and instantaneous device
status reporting. I²CTM is a bi-directional 2-wire serial interface developed by Philips Semiconductor (now NXP
Semiconductors). Only two bus lines are required: a serial data line (SDA) and a serial clock line (SCL). Devices
can be considered as masters or slaves when performing data transfers. A master is the device which initiates a
data transfer on the bus and generates the clock signals to permit that transfer. At that time, any device
addressed is considered a slave.
The device operates as a slave device with address 6BH, receiving control inputs from the master device like
micro controller or a digital signal processor through REG00-REG0B. Register read beyond REG0B (0x0B)
returns 0xFF. The I²C interface supports both standard mode (up to 100 kbits), and fast mode (up to 400 kbits).
connecting to the positive supply voltage via a current source or pull-up resistor. When the bus is free, both lines
are HIGH. The SDA and SCL pins are open drain.
7.3.11.1 Data Validity
The data on the SDA line must be stable during the HIGH period of the clock. The HIGH or LOW state of the
data line can only change when the clock signal on the SCL line is LOW. One clock pulse is generated for each
data bit transferred.
Copyright © 2017, Texas Instruments Incorporated
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