BQ27000 Datasheet, PDF (22/29 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
Temperature compensation, TCMP, is computed from these coefficients as follows:
TCMP = TCGN * ILMD(273 + TOFF - T)/4
where T is the temperature in °K and TCMP ≥ 0. CACT is then computed as follows:
CACT = CACD – TCMP
If PKCFG[0] = 1, the device assumes a fixed value of 0x7C for TCOMP, giving a temperature compensation gain
of 0.68% DC/°C with an offset of 12°C. This frees the EEPROM location of 0x7F for use as a programmable
identification byte.
Power Modes
The bqJUNIOR has five power modes: Active, Sleep, Ship, Hibernate, and Data Retention (RBI). Figure 5 shows
the flow that moves the device between the Active, Sleep, and Ship modes. Hibernate and Data Retention are
special modes not included in the flow. Detailed explanations of each mode follow the diagram in Figure 5.
Active Mode
COM low for 18 ^No
seconds?
Yes
Ship
enabled?
No
Yes
Ship Mode
No
V_SR
below DMF
threshold?
Yes
Sleep Mode
COM
No
pulled high?
COM
No
pulled high?
43.6 minute
No
wake?
Yes
Yes
Yes
Device enters active
mode for 18 seconds
Figure 5. Power Mode Flow Chart
UDG−04101
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