BQ25600 Datasheet, PDF (21/66 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
7.3.3.6 Converter Power-Up
After the input current limit is set, the converter is enabled and the HSFET and LSFET start switching. If battery
charging is disabled, BATFET turns off. Otherwise, BATFET stays on to charge the battery.
The device provides soft-start when system rail is ramped up. When the system rail is below 2.2 V, the input
current is limited to is to the lower of 200 mA or IINDPM register setting. After the system rises above 2.2 V, the
device limits input current to the value set by IINDPM register.
As a battery charger, the device deploys a highly efficient 1.5 MHz step-down switching regulator. The fixed
frequency oscillator keeps tight control of the switching frequency under all conditions of input voltage, battery
voltage, charge current and temperature, simplifying output filter design.
The device switches to PFM control at light load or when battery is below minimum system voltage setting or
charging is disabled. The PFM_DIS bit can be used to prevent PFM operation in either buck or boost
configuration.
7.3.4 Boost Mode Operation From Battery
The device supports boost converter operation to deliver power from the battery to other portable devices
through USB port. The boost mode output current rating meets the USB On-The-Go 500 mA output requirement.
The maximum output current is up to 1.2 A. The boost operation can be enabled if the conditions are valid:
1. BAT above V_{OTG_BAT}
2. VBUS less than BAT+V_SLEEP (in sleep mode)
3. Boost mode operation is enabled (OTG_CONFIG bit = 1)
4. Voltage at TS (thermistor) pin is within acceptable range (V_BHOT < V_TS < V_BCOLD)
5. After 30-ms delay from boost mode enable
During boost mode, the status register VBUS_STAT bits is set to 111, the VBUS output is 5.15 V and the output
current can reach up to 1.2 A, selected through I²C (BOOST_LIM bit). The boost output is maintained when BAT
is above V_{OTG_BAT} threshold.
When OTG is enabled, the device starts up with PFM and later transits to PWM to minimize the overshoot. The
PFM_DIS bit can be used to prevent PFM operation in either buck or boost configuration.
7.3.5 Host Mode and Standalone Power Management
7.3.5.1 Host Mode and Default Mode in bq25600 and bq25600D
The bq25600 and bq25600D is a host controlled charger, but it can operate in default mode without host
management. in default mode, the device can be used as an autonomous charger with no host or while host is in
sleep mode. When the charger is in default mode, WATCHDOG_FAULT bit is HIGH. When the charger is in host
mode, WATCHDOG_FAULT bit is LOW.
After power-on-reset, the device starts in default mode with watchdog timer expired, or default mode. All the
registers are in the default settings. During default mode, any change on PSEL pin will make real time IINDPM
register changes.
in default mode, the device keeps charging the battery with default 10-hour fast charging safety timer. At the end
of the 10-hour, the charging is stopped and the buck converter continues to operate to supply system load.
Writing a 1 to the WD_RST bit transitions the charger from default mode to host mode. All the device parameters
can be programmed by the host. To keep the device in host mode, the host has to reset the watchdog timer by
writing 1 to WD_RST bit before the watchdog timer expires (WATCHDOG_FAULT bit is set), or disable watchdog
timer by setting WATCHDOG bits = 00.
When the watchdog timer expires (WATCHDOG_FAULT bit = 1), the device returns to default mode and all
registers are reset to default values except IINDPM, VINDPM, BATFET_RST_EN, BATFET_DLY, and
BATFET_DIS bits.
Copyright © 2017, Texas Instruments Incorporated
Product Folder Links: bq25600 bq25600D
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