BQ2060SS Datasheet, PDF (44/59 Pages) Texas Instruments – SBS V1.1-COMPLIANT GAS GAUGE IC

bq2060
SLUS035E – JANUARY 2000 – REVISED OCTOBER 2005
www.ti.com
EEPROM PROGRAMMING (continued)
Charge Efficiency + 10 (EFF% * 74.5)
(15)
where
74.5 ≤ EFF% ≤ 100
ERR% is encoded in Efficiency Reduction Rate EE 0x65 according to the following equation:
Efficiency
Reduction
Rate
+
ERR%
0.0125
(16)
where
• 0 ≤ ERR% ≤ 3.19
The Efficiency Drop Off Percentage is stored in 2s complement of percent.
The bq2060 also adjusts the efficiency factors for temperature. TEFF% defines the percent efficiency reduction
per degree C over 25°C. TEFF% is encoded in Efficiency Temperature Compensation EE 0x63 according to the
following equation
Efficiency Temperature Compensation +
TEFF% 1.6
0.0125
(17)
where
• 0 ≤ TEFF%≤ 1.99
The bq2060 applies all four charge-compensation factors when the CHEM bit in Pack Configuration is not set,
denoting a nickel pack.
Effective Charge Efficiency Reduction (nickel only)
% + ERR%[RSOC * EDOP%] ) TEFF%[Temperature * 25^oC] ) EFF%
(18)
where
• RSOC() ≤ EFF% and T≥ 25°C
If CHEM is set denoting a Li-ion pack, the bq2060 applies only the value coded in High Charge Efficiency and
makes no other adjustments for charge acceptance.
CHARGE LIMITS AND TERMINATION TECHNIQUES
Charging Voltage
The 16-bit value, Charging Voltage EE 0x0a-0x0b programs the ChargingVoltage() value broadcast to a Smart
Charger. It is also sets the base value for determining overvoltage conditions during charging and voltage
compliance during a constant-voltage charging methodology. It is stored in mV.
Overvoltage
The 8-bit value, Overvoltage Margin EE 0x48, sets the limit over ChargingVoltage() that is to be considered as
an overvoltage charge-suspension condition. The voltage in mV above the ChargingVoltage(), VOVM, that
should trigger a charge suspend is encoded in Overvoltage Margin as follows:
Overvoltage
Margin
+
VOVM
16
(19)
where
• VOVM is between 0 and 4080 mV.
Charging Current
ChargingCurrent() values are either broadcast to a Level 2 Smart Battery Charger or read from the bq2060 by a
Level 3 Smart Battery Charger. The bq2060 sets the value of ChargingCurrent(), depending on the charge
requirements and charge conditions of the pack.
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