BQ27000 Datasheet, PDF (18/29 Pages) Texas Instruments – SINGLE CELL Li-Ion AND Li-Pol BATTERY GAS GAUGE IC FOR PORTABLE APPLICATIONS (bqJUNIOR)

bq27000, bq27200
SLUS556B – SEPTEMBER 2004 – REVISED NOVEMBER 2004
www.ti.com
Cycle Count Since Learning Cycle Registers (CYCLL/CYCLH) — Address 0x28/0x29
CYCL is the cycle count since the last learning cycle. Each count indicates an increment of CYCT since there
was a learning cycle. This register is cleared every time there is a learning cycle. When this count reaches 32, it
forces the CI flag in FLAGS to a 1. The host system has read-only access to this register pair.
Cycle Count Total Registers (CYCTL/CYCTH) — Address 0x2A/0x2B
CYCT is the cycle count since a full reset. A full reset clears this register. Each count indicates a cumulative
discharge equal to the Design Capacity (256 * ILMD). The host system has read-only access to this register pair.
Compensated State-of-Charge (CSOC) — Address 0x2C
CSOC reports the compensated available capacity as a percentage of the last measured discharge value (LMD).
The equation is:
CSOC (%) = 100 * CACT/LMD
The host system has read-only access to this register.
Reserved Registers
Addresses 0x2D — 0x6D and Address 0x6F — 0x75 are reserved and cannot be written by host.
EEPROM Enable Register (EE_EN) — Address 0x6E
This register is used to enable host writes to EEPROM data locations (addresses 0x76 — 0x7F). The host must
write data 0xDD to this register to enable EEPROM programming. See the Programming the EEPROM section
for further information on programming the EEPROM bytes. Care should be taken to insure that no value except
0xDD is written to this location.
EEPROM Data Registers (EE_DATA) — Address 0x76 — 0x7F
The EEPROM data registers contain information vital to the performance of the device. These registers are to be
programmed during pack manufacturing to allow flexibility in the design values of the battery to be monitored.
The EEPROM data registers are listed in Table 2. Detailed descriptions of what should be programmed follow.
See the Programming the EEPROM section for detailed information on writing the values to EEPROM.
Address
0x7F
0x7E
0x7D
0x7C
0x7B
0x7A
0x79
0x78
0x77
0x76
Table 2. bq27000/bq27200 EEPROM Memory Map
Name
TCOMP
DCOMP
IMLC
PKCFG
TAPER
DMFSD
ISLC
SEDV1
SEDVF
ILMD
Function
Temperature compensation constants, OR, ID#1
Discharge rate compensation constants, OR, ID#2
Initial max load current, OR, ID#3
Pack configuration values
Aging estimate enable [7], charge termination taper current [6:0]
Digital magnitude filter and self-discharge rate constants
Initial standby load current
Scaled EDV1 threshold
Scaled EDVF threshold
Initial last measured discharge high byte
Initial Last Measured Discharge High Byte (ILMD) — Address 0x76
This register contains the scaled design capacity of the battery to be monitored. The equation to calculate the
initial LMD is:
ILMD = Design Capacity(mAh) * R_S(mΩ) / (256*3.57)
where R_S is the value of the sense resistor used in the system. This value is used to initialize the high byte of
LMD. The initial low byte value of LMD is 0.
18