BQ25601 Datasheet, PDF (28/60 Pages) Texas Instruments – I2C Controlled 3-A, Single-Cell Battery Charger for High Input Voltage and Narrow Voltage DC (NVDC) Power Path Management

bq25601
SLUSCK5 – MARCH 2017
www.ti.com
When a fault occurs, the charger device sends out INT and keeps the fault state in REG09 until the host reads
the fault register. Before the host reads REG09 and all the faults are cleared, the charger device would not send
any INT upon new faults. To read the current fault status, the host has to read REG09 two times consecutively.
The first read reports the pre-existing fault register status and the second read reports the current fault register
status.
8.4.10 Protections
8.4.10.1 Voltage and Current Monitoring in Converter Operation
The device closely monitors the input and system voltage, as well as internal FET currents for safe buck and
boost mode operation.
8.4.10.1.1 Voltage and Current Monitoring in Buck Mode
8.4.10.1.1.1 input Overvoltage (ACOV)
If VBUS voltage exceeds V_{VAC_OV} (programmable via OVP[2:0] bits), the device stops switching immediately.
During input overvoltage event (ACOV), the fault register CHRG_FAULT bits are set to 01. An INT pulse is
asserted to the host. The device will automatically resume normal operation once the input voltage drops back
below the OVP threshold.
8.4.10.1.1.2 System Overvoltage Protection (SYSOVP)
The charger device clamps the system voltage during load transient so that the components connect to system
would not be damaged due to high voltage. SYSOVP threshold is 350 mV above system regulation voltage.
Upon SYSOVP, converter stops immediately to clamp the overshoot. The charger provides 30 mA discharge
current to bring down the system voltage.
8.4.10.2 Voltage and Current Monitoring in Boost Mode
The device closely monitors the VBUS voltage, as well as RBFET and LSFET current to ensure safe boost mode
operation.
8.4.10.2.1 VBUS Soft Start
When the boost function is enabled, the device soft-starts boost mode to avoid inrush current.
8.4.10.2.2 VBUS Output Protection
The device monitors boost output voltage and other conditions to provide output short circuit and overvoltage
protection. The Boost build in accurate constant current regulation to allow OTG to adaptive to various types of
load. If short circuit is detected on VBUS, the Boost turns off and retry 7 times. If retries are not successful, OTG
is disabled with OTG_CONFIG bit cleared. In addition, the BOOST_FAULT bit is set and INT pulse is generated.
The BOOST_FAULT bit can be cleared by host by re-enabling boost mode
8.4.10.2.3 Boost Mode Overvoltage Protection
When the VBUS voltage rises above regulation target and exceeds VOTG_OVP, the device enters overvoltage
protection which stops switching, clears OTG_CONFIG bit and exits boost mode. At Boost overvoltage duration,
the fault register bit (BOOST_FAULT) is set high to indicate fault in boost operation. An INT is also asserted to
the host.
8.4.10.3 Thermal Regulation and Thermal Shutdown
8.4.10.3.1 Thermal Protection in Buck Mode
The bq25601 monitors the internal junction temperature T_J to avoid overheat the chip and limits the IC surface
temperature at 110ºC 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.
28
Submit Documentation Feedback
Product Folder Links: bq25601
Copyright © 2017, Texas Instruments Incorporated