Datasheet

bq34z100

www.ti.com

SLUSAU1B –MAY 2012–REVISED DECEMBER 2012

POWER MODES

The bq34z100 has three power modes: NORMAL mode, SLEEP mode, and FULLSLEEP mode.

• In NORMAL mode, the bq34z100 is fully powered and can execute any allowable task.

• In SLEEP mode, the gas gauge exists in a reduced-power state, periodically taking measurements and

performing calculations.

• In FULLSLEEP mode, the high frequency oscillator is turned off, and power consumption is further reduced

compared to SLEEP mode.

NORMAL Mode

The gas gauge is in NORMAL mode when not in any other power mode. During this mode, AverageCurrent(),

Voltage() and Temperature() measurements are taken, and the interface data set is updated. Decisions to

change states are also made. This mode is exited by activating a different power mode.

SLEEP Mode

SLEEP mode is entered automatically if the feature is enabled (Pack Configuration [SLEEP] = 1) and Average

Current() is below the programmable level Sleep Current. Once entry to sleep has been qualified but prior to

entry to SLEEP mode, the bq34z100 performs an ADC autocalibration to minimize offset. Entry to SLEEP mode

can be disabled by the [SLEEP] bit of Pack Configuration(), where 0 = disabled and 1 = enabled. During SLEEP

mode, the bq34z100 periodically wakes to take data measurements and updates the data set, after which it then

returns directly to SLEEP. The bq34z100 exits SLEEP if any entry condition is broken, a change in protection

status occurs, or a current in excess of I

WAKE

through R

SENSE

is detected.

FULLSLEEP Mode

FULLSLEEP mode is entered automatically when the bq34z100 is in SLEEP mode and the timer counts down to

0 (Full Sleep Wait Time > 0). FULLSLEEP mode is disabled when Full Sleep Wait Time is set to 0.

During FULLSLEEP mode, the bq34z100 periodically takes data measurements and updates its data set.

However, a majority of its time is spent in an idle condition.

The gauge exits the FULLSLEEP mode when there is any communication activity. Therefore, the execution of

SET_FULLSLEEP sets [FULLSLEEP] bit, but the EVSW might still display the bit clear. The FULLSLEEP mode

can be verified by measuring the current consumption of the gauge. In this mode, the high frequency oscillator is

turned off. The power consumption is further reduced compared to the SLEEP mode.

While in FULLSLEEP mode, the fuel gauge can suspend serial communications as much as 4 ms by holding the

communication line(s) low. This delay is necessary to correctly process host communication since the fuel gauge

processor is mostly halted. For HDQ communication one host message will be dropped.

Product Folder Links: bq34z100