BQ25703A Datasheet, PDF (52/81 Pages) Texas Instruments – I2C Multi-Chemistry Battery Buck-Boost Charge Controller With System Power Monitor and Processor Hot Monitor

bq25703A
SLUSCU1 – MAY 2017
www.ti.com
8.6.4 MaxChargeVoltage Register (I2C address = 05/04h) [reset value based on CELL_BATPRESZ pin
setting]
To set the output charge voltage, write a 16-bit ChargeVoltage register command (REG0x05/04()) using the data
format listed in Table 25 and Table 26. The charger provides charge voltage range from 1.024 V to 19.200 V,
with 16-mV step resolution. Any write below 1.024 V or above 19.200 V is ignored. Upon POR or when charge is
disabled, the system is regulated at the MaxChargeVoltage register.
Upon POR, REG0x05/04() is by default set as 4192 mV for 1 s, 8400 mV for 2 s, 12592 mV for 3 s or 16800 mV
for 4 s. After CHRG_OK, if host writes REG0x03/02() before REG0x05/04(), the charge will start after the write to
REG0x03/02().If the battery is different from 4.2 V/cell, the host has to write to REG0x05/04() before
REG0x03/02() for correct battery voltage setting. Writing REG0x05/04() to 0 will set REG0x05/04() to default
value on CELL_BATPRESZ pin, and force REG0x03/02() to zero to disable charge.
The SRN pin is used to sense the battery voltage for voltage regulation and should be connected as close to the
battery as possible, and directly place a decoupling capacitor (0.1 µF recommended) as close to the device as
possible to decouple high frequency noise.
Figure 33. MaxChargeVoltage Register (I2C address = 05/04h) [reset value based on CELL_BATPRESZ
pin setting]
15
Reserved
R/W
14
Max Charge
Voltage, bit 10
R/W
13
Max Charge
Voltage, bit 9
R/W
12
Max Charge
Voltage, bit 8
R/W
11
Max Charge
Voltage, bit 7
R/W
10
Max Charge
Voltage, bit 6
R/W
9
Max Charge
Voltage, bit 5
R/W
8
Max Charge
Voltage, bit 4
R/W
7
6
5
4
3
2
1
0
Max Charge Max Charge Max Charge Max Charge
Voltage, bit 3 Voltage, bit 2 Voltage, bit 1 Voltage, bit 0
Reserved
R/W
R/W
R/W
R/W
R/W
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 25. MaxChargeVoltage Register (I2C address = 05h) Field Descriptions
I2C
05h
FIELD
TYPE
RESET
DESCRIPTION
7
Reserved
R/W
0b
Not used. 1 = invalid write.
6
Max Charge Voltage, bit 10
R/W
0b
0 = Adds 0 mV of charger voltage.
1 = Adds 16384 mV of charger voltage.
5
Max Charge Voltage, bit 9
R/W
0b
0 = Adds 0 mV of charger voltage.
1 = Adds 8192 mV of charger voltage
4
Max Charge Voltage, bit 8
R/W
0b
0 = Adds 0 mV of charger voltage.
1 = Adds 4096 mV of charger voltage.
3
Max Charge Voltage, bit 7
R/W
0b
0 = Adds 0 mV of charger voltage.
1 = Adds 2048 mV of charger voltage.
2
Max Charge Voltage, bit 6
R/W
0b
0 = Adds 0 mV of charger voltage.
1 = Adds 1024 mV of charger voltage.
1
Max Charge Voltage, bit 5
R/W
0b
0 = Adds 0 mV of charger voltage.
1 = Adds 512 mV of charger voltage.
0
Max Charge Voltage, bit 4
R/W
0b
0 = Adds 0 mV of charger voltage.
1 = Adds 256 mV of charger voltage.
Table 26. MaxChargeVoltage Register (I2C address = 04h) Field Descriptions
I2C
04h
FIELD
7
Max Charge Voltage, bit 3
TYPE
R/W
RESET
0b
DESCRIPTION
0 = Adds 0 mV of charger voltage.
1 = Adds 128 mV of charger voltage.
52
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