BQ24747 Datasheet, PDF (24/36 Pages) Texas Instruments – SMBus-Controlled Level 2 Multi-Chemistry Battery Charger With Input Current Detect Comparator and Charge Enable Pin

bq24747
SLUS988 – OCTOBER 2009 ............................................................................................................................................................................................. www.ti.com
SMBCLK
A
B
tLOW tHIGH
C
D
EF
G
H
I
J
K
SMBDATA
A = START CONDITION
B = MSB OF ADDRESS CLOCKED INTO SLAVE
C = LSB OF ADDRESS C LOCKED INTO SLAVE
D = R/W BIT CLOCKED INTO SLAVE
E = SLAVE PULLS SMBDATA LINE LOW I = ACKNOWLEDGE CLOCK PULSE
F = ACKNOWLEDGE BIT CLOCKED INTO MASTER J = STOP CONDITION
G = MSB OF DATA CLOCKED INTO MASTER K = NEW START CONDITION
H = LSB OF DATA CLOCKED INTO MASTER
Figure 36. SMBus Read Timing
SETTING THE CHARGE VOLTAGE
To program the output charge voltage regulation setpoint, use the SMBus to write a 16-bit ChargeVoltage()
command using the data format listed in Table 3. The ChargeVoltage() command uses the Write-Word protocol
(see Figure 34). The command code for ChargeVoltage() is 0x15 (0b00010101). The bq24747 provides a
charge-voltage range of 1.024 V to 19.200 V, with 16 mV resolution. Set ChargeVoltage() below 1.024 V to
terminate charging. Upon reset, the ChargeVoltage() and ChargeCurrent() values are cleared and the charger
remains off until both the ChargeVoltage() and the ChargeCurrent() command are sent. Both UGATE and
LGATE pins remain low until the charger is restarted.
Table 3. Charge Voltage Register (0x15)
BIT
BIT NAME
DESCRIPTION
0
–
Not used.
1
–
Not used.
2
–
Not used.
3
–
Not used.
4
Charge Voltage, DACV 0
0 = Adds 0 mV of charger voltage, 1024 mV min.
1 = Adds 16 mV of charger voltage
5
Charge Voltage, DACV 1
0 = Adds 0 mV of charger voltage, 1024 mV min.
1 = Adds 32 mV of charger voltage
6
Charge Voltage, DACV 2
0 = Adds 0 mV of charger voltage, 1024 mV min.
1 = Adds 64 mV of charger voltage.
7
Charge Voltage, DACV 3
0 = Adds 0 mV of charger voltage, 1024 mV min.
1 = Adds 128 mV of charger voltage.
8
Charge Voltage, DACV 4
0 = Adds 0 mV of charger voltage, 1024 mV min.
1 = Adds 256 mV of charger voltage.
9
Charge Voltage, DACV 5
0 = Adds 0 mV of charger voltage, 1024 mV min.
1 = Adds 512 mV of charger voltage
10
Charge Voltage, DACV 6
0 = Adds 0 mV of charger voltage.
1 = Adds 1024 mV of charger voltage.
11
Charge Voltage, DACV 7
0 = Adds 0 mV of charger voltage.
1 = Adds 2048 mV of charger voltage.
12
Charge Voltage, DACV 8
0 = Adds 0 mV of charger voltage.
1 = Adds 4096 mV of charger voltage.
13
Charge Voltage, DACV 9
0 = Adds 0 mV of charger voltage.
1 = Adds 8192 mV of charger voltage.
14
Charge Voltage, DACV 10
0 = Adds 0 mV of charger voltage.
1 = Adds 16384 mV of charger voltage.
15
–
Not used.
24
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