BQ2063_15 Datasheet, PDF (54/60 Pages) Texas Instruments – SBS v1.1-COMPLIANT Li-ION GAS-GAUGE IC

bq2063
Not Recommended For New Designs
SBS v1.1ĆCOMPLIANT LiĆION GASĆGAUGE IC
WITH PROTECTOR INTERFACE
SLUS468E− MAY 2001 − REVISED APRIL 2002
PROGRAMMING INFORMATION
measurement calibration (continued)
current
The bq2063 scales Current( ) to mA units by the 16-bit value ADC Sense Resistor Gain in EE 0x68-0x69.
Adjusting ADC Sense Resistor Gain from its nominal value provides a method to calibrate the current readings
for variances in the ADC gain, internal voltage reference, and sense resistor value. The bq2063 calculates
Current( ) by
ƪ ƫ Current( ) +
(ADC Reading ) ADC Offset) _* ADC Sense Resistor Gain
16384
(30)
The nominal value for ADC Sense Resistor Gain is given by equation (4).
ADC Offset in EE 0x62 adjusts the ADC reading for bq2063 measurement offset. ADC Offset is a signed 8-bit
value that cancels offset present in the ADC measurement. ADC Offset is typically between –20 and 20.
vfc
To calibrate the coulomb counting measurement for VFC gain errors and sense resistor tolerance, the value
of VFC Sense Resistor Gain EE 0x6a-0x6b may be adjusted from its nominal value.
The nominal value of VFC Sense Resistor Gain is given by equation (6).
The bq2063 VFC circuit has the ability to introduce a signal opposite in sign to the inherent device and circuit
offset to cancel this error. The offset calibration routine is initiated with commands to ManufacturerAccess( ).
The bq2063 calculates the offset with the calibration routine and stores the calibration value using the least 21
bits of VFC Offset in EE 0x5e-0x60.
The least 20 bits store the offset calibration value (OCV). The sign of the offset calibration value is positive if
the 21st bit is 0.
OCV
+
VFC
0.6 V
Offset_19–0
(31)
temperature
The bq2063 uses Temperature Offset in EE 0x61 to calibrate the Temperature( ) function for offset. The required
offset adjustment, TOFF (°C), sets Temperature Offset according to the equation
Temperature Offset + TOFF _* 10
(32)
Where:
–12.8 ≤ TOFF ≤ 12.7
constants and string data
EEPROM constants
Check Byte 1 EE 0x00-0x01 and Check Byte 2 EE 0x7e-0x7f must be programmed to 0x3c7f and 0xa55a,
respectively.
specification information
Specification Information EE 0x14-0x15 stores the default value for the SpecificationInfo( ) function. It is stored
in EEPROM in the same format as the data returned by the SepcificationInfo( ).
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