BQ24721 Datasheet, PDF (33/48 Pages) Texas Instruments – ADVANCED MULTI-CHEMISTRY AND MULTI-CELL SYNCHRONOUS SWITCH-MODE CHARGER AND SYSTEM POWER SELECTOR

bq24721
www.ti.com
SLUS683 – NOVEMBER 2005
SBS-Like SMBus
SBS-Like interface is not 100% SBS compliant, as control and status registers were changed to simplify and
enhance the charger control device. Address 0x12 is used, but the charger should not to be used on systems
requiring 100% SBS compliance. Effort was taken to use the same commands when possible. Comparison
included on SBS-like vs SBS Spec.
• SBS-Like SMBus
– SBS 1.1 protocol, slave operation only
– No CRC
– Address: 12 (Note SBS-Like is not 100% SBS compliant and has simplified enhancements and
• Smart charger commands implemented
– ChargingCurrent (), with modifications on data byte contents, SBS-Like SMBus
– ChargingVoltage (), with modifications on data byte contents, SBS-Like SMBus
– ChargerStatus (), with modifications on status bits
• Smart charger commands not implemented
– ChargerSpecInfo (),
– AlarmWarning ()
SBS-Like SMBus: Commands Implemented: Charge Current DAC Register
Charging Current, (0x14), Write/Read⁽¹⁾
Table 1.
BIT
0 (LSB)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15 (MSB)
SBS SPEC
1 mA
2 mA
4 mA
8 mA
16 mA
32 mA
64 mA
128 mA
256 mA
512 mA
1024 mA
2048 mA
4096 mA
8192 mA
16384 mA
32768 mA
bq24721 SBS-Like
NA
NA
NA
NA
NA
NA
NA
128 mA (1.28 mV)
256 mA (2.56 mV)
512 mA (5.12 mV)
1024 mA (10.24 mV)
2048 mA (20.48 mV)
4096 mA (40.96 mV)
8192 mA (81.92 mV)
NA
NA
NOTES
Charge current limit setting
16384 mA max
(162.56 mV max)
(1) Note: Shunt drop voltage shown at LO/HI bit state;
DAC current value is based on using 10 mΩ sense resistor.
Max charge current with 10 mΩ sense resistor is 16.256 A.
Bit 13 allows using larger sense resistors for increasing accuracy in low charge current applications.
• Valid charge currents are 0 A–16.256 A using a 10 mΩ sense resistor. Minimum step is 128 mA.
• Programmed charge currents above max 16.256 A → Charger is enabled and the current regulation value is
set to the maximum 16.256 A.
• Programmed charge current = 0 A → Charger is disabled.
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