BQ26221 Datasheet, PDF (9/20 Pages) Texas Instruments – HIGH PERFORMANCE BATTERY MONITOR IC WITH COUOMB COUNTER, VOLTAGE AND, TEMPERATURE MEASUREMENT

bq26221
APPLICATION INFORMATION
SLUS607 − MAY 2004
Table 2. WOE Thresholds
WOE_3–1 (HEX)
0h
1h
2h
3h
4h
5h
6h
7h
V_WOE (mV)
n/a
3.516
1.758
1.172
0.879
0.703
0.586
0.502
Table 3. Operational States
MODE
Normal
Sleep
Hibernate
ACTIVE REGISTERS
CCR, DCR, CTC, DTC, SDR
SDR
No active registers
hibernate mode operation
The bq26221 enters hibernate mode when Vcc drops below the POR threshold, V_(POR). In this mode, the
bq26221 draws current from the RBI pin to maintain RAM data. The bq26221 exits hibernate mode only when
Vcc is raised above the POR threshold.
current sense offset calibration and compensation
The bq26221 automatically and continuously compensates for V_(SRP) − V_(SRN) offset. No host calibration or
compensation is required.
gas gauge control registers
The host maintains the charge and discharge and the self-discharge count registers (CCR, CTC, DCR, DTC,
and SCR). To facilitate this maintenance, the bq26221 CLR register resets the specific counter or register pair
to zero. The host system clears a register by writing the corresponding register bit to 1. When the bq26221
completes the reset, the corresponding bit in the CLR register is automatically reset to 0. Clearing the DTC or
CTC registers clears the MODE register bits STC/STD and sets the CTC/DTC count rates to the default value
of 1.138 counts per second.
device temperature measurement
The bq26221 reports die temperature in units of ^oK through register pair TMPH−TMPL. Refer to the TMP
register description for more details.
www.ti.com
9