BQ27425-G1 Datasheet, PDF (20/32 Pages) Texas Instruments – System-Side Impedance Track™ Fuel Gauge With Integrated Sense Resistor

bq27425-G1
SLUSAI6 – NOVEMBER 2011
DETAILED PIN DESCRIPTIONS
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The Operation Configuration Register
Two bq27425 pins are configured via the Operation Configuration data NVM register, as indicated in Table 8.
This register is programmed/read via the methods described in Section Accessing the Data NVM.
High Byte
Low Byte
bit7
INTSNSEN
RSVD1
Table 8. Operation Configuration Bit Definition
bit6
RSVD0
RSVD1
bit5
BIE
SLEEP
bit4
BI_PU_EN
RMFCC
bit3
GNDSEL
RSVD1
bit2
RSVD0
BATLOWEN
bit1
RSVD0
GPIOPOL
bit0
RSVD1
WRTEMP
INTSNSEN = Enables temperature compensation of the integrated sense resistor. Default is 0.
BIE =
Battery Insertion Enable. If set, the battery insertion is detection via BIN pin input. If cleared, the detection relies on the
host to issue BAT_INSERT subcommand to indicate battery presence in the system. Default is 0.
BI_PU_EN = Enables internal weak pull-up on BIN pin. Default is 0 which assumes an external pull-up resistor.
GNDSEL =
The ADC ground select control. The Vss (Pin D1) is selected as ground reference when the bit is clear. Pin A1 is
selected when the bit is set. Default is 0.
SLEEP = The fuel gauge can enter sleep, if operating conditions allow. True when set. Default is 1.
RMFCC = RM is updated with the value from FCC, on valid charge termination. True when set. Default is 1.
BATLOWEN =
If set, the BAT_LOW function for GPOUT pin is selected. If cleared, the SOC_INT function is selected for GPOUT.
Default is 0.
GPIO_POL = GPOUT pin is active-high if set or active-low if cleared. Default is 0.
WRTEMP = Enables the host to write Temperature( ) if set. If cleared, the internal temperature sensor is used for Temperature( ).
Default is 0.
RSVD0 = Reserved. Default is 0. (Set to 0 for proper operation)
RSVD1 = Reserved. Default is 1. (Set to 1 for proper operation)
GPOUT Pin
The GPOUT Pin is a multiplex pin and the polarity of the pin output can be selected via the [GPIO_POL] bit of
the Operation Configuration. The function is defined by [BATLOWEN]. If set, the Battery Low Indicator
(BAT_LOW) function for GPOUT pin is selected. If cleared, the SOC interrupt (SOC_INT) function is selected for
GPOUT.
When the BAT_LOW function is activated, the signaling on the multiplexed pin follows the status of the [SOC1]
bit in the Flags( ) register. The bq27425 has two flags accessed by the Flags( ) function that warns when the
battery’s SOC has fallen to critical levels. When StateOfCharge( ) falls below the first capacity threshold,
specified in SOC1 Set Threshold, the [SOC1] (State of Charge Initial) flag is set. The flag is cleared once
StateOfCharge( ) rises above SOC1 Set Threshold. The bq27425’s GPOUT pin automatically reflects the status
of the [SOC1] flag when OpConfig[BATLOWEN=0].
When StateOfCharge( ) falls below the second capacity threshold, SOCF Set Threshold, the [SOCF] (State of
Charge Final) flag is set, serving as a final discharge warning. Similarly, when StateOfCharge( ) rises above
SOCF Clear Threshold and the [SOCF] flag has already been set, the [SOCF] flag is cleared.
When the SOC_INT function is activated, the GPOUT pin generates 1ms pulse width under various conditions as
described in Table 9.
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