BQ24152 Datasheet, PDF (19/38 Pages) Texas Instruments – Fully Integrated Switch-Mode One-Cell Li-Ion Charger with Full USB Compliance and USB-OTG Support

bq24152
www.ti.com ...................................................................................................................................................................................................... SLUS847 – JUNE 2008
Charge Status Output, STAT Pin
The STAT pin is used to indicate operation conditions for bq24152. 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
STAT
Charge in progress and EN_STAT = 1
Low
Other normal conditions
Open-drain
Charge mode faults: Timer fault, sleep mode, VBUS 128-µs pulse, then open-drain
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
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 bq24152 charges the related
operation modes if HZ_MODE is set to "0", refer to Table 2 for detail.
OPA_MODE
0
1
X
Table 2. Operation Mode Summary
HZ_MODE
0
0
1
OPERATION MODE
Charge (no fault)
Charge configure (fault, V_bus > V_UVLO)
High impedance (V_bus < V_UVLO)
Boost (no faults)
Any fault go to charge configure mode
High impedance
Boost Mode Operation
In 32 second mode, when the OTG pin is in active status or the bit of operation mode (OPA_MODE) at control
register is set to 1, the bq24152 operates in boost mode and delivers the power to VBUS from the battery. At
normal boost mode, bq24152 converts the battery voltage (2.5 V to 4.5 V) to VBUS-B (about 5.05V) and delivers
a current as much as I_(BO) (approximately 200 mA) to support other USB OTG devices connected to the USB
connector.
PWM Controller in Boost Mode
Similar to charge mode operation, in boost mode, the bq24152 provides an integrated, fixed 3 MHz frequency
voltage-mode controller to regulate output voltage at PMID pin (VPMID), as shown in Figure 22. The voltage
control loop is internally compensated using a Type-III compensation scheme that provides enough phase
margin for stable operation with a wide load range and battery voltage range
Copyright © 2008, Texas Instruments Incorporated
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