System Current
0
GE LOW
GE HIGH
25
SLUUBH1C–August 2016–Revised March 2018
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Copyright © 2016–2018, Texas Instruments Incorporated
Power Control
Chapter 6
SLUUBH1C–August 2016–Revised March 2018
Power Control
The bq35100 device has only one active power mode that is enabled through the GAUGE ENABLE (GE)
pin. The power consumption of the bq35100 device can change significantly based on host commands
that it receives and its default configuration, specifically with respect to data flash updates.
6.1 Device Functional Modes
The bq35100 device is intended for systems where the battery electronics are required to consume a very
low average current. To achieve this, the device is intended to be fully powered off when not required
through control of the GAUGE ENABLE pin.
When this pin is low, then the device is fully powered down where no measurements are made and no
data, unless in flash, is retained. In this state, the power consumption of the device is a few 10s of nA.
This value is primarily leakage of the device and other components on the board, but also includes
measurement errors. Due to the level of possible variations, use a conservative value of 50 nA for
example calculations.
An example system current profile is shown along with the state of GE to reduce the average power
consumption of the battery electronics.
Figure 6-1. System Current Profile Example
The average power consumption of the bq35100 device is an average of the periods where GAUGE
ENABLE is high AND low over a given period.
For example, if the system enters a high power state (315 µA) for 30 s every 4 hours, the average current
will be:
315 µA × 30 s / 4 hrs = 0.66 µA (4)
When GAUGE ENABLE is low (GE = Low), then the device is powered off and the current is nominally
I
CC_GELOW
and is the leakage current into the REGIN pin. Other components connected to this node should
also be evaluated to determine the "System Off" current total.
When the device is used for gas gauging, it transitions through several power states based on the
selection of Operation Cfg A[GMSEL].
Figure 6-2 highlights the operational flow and conditional decisions.
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