TEXAS INSTRUMENTS bq2063 Technical data

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bq2063

SBS v1.1-COMPLIANT Li-ION GAS-GAUGE IC

WITH PROTECTOR INTERFACE

SLUS468E– MA Y 2001 – REVISED APRIL 2002

D Provides Accurate Measurement of

Available Charge in Li-Ion Batteries

D Supports the 2-Wire SMBus V1.1 Interface

With PEC or Single-Wire HDQ16

D Directly Interfaces the Seiko S-8243

Protection IC for Maximum Safety Protection and Minimal Component Count

D Supports Internal or External Thermistor D Reports Individual Cell Voltages D Uses 15-Bit ADC for Accurate Voltage,

T emperature, and Current Measurements

D Measures Charge Flow Using A V-to-F

Converter With Offset of Less Than 16 µV After Calibration

HDQ16

ESCL

ESDA

RBI

REG

VOUT

VCC

VSS CTL2 CTL3 CTL4 LED1 LED2 LED3

SSOP (DBQ) PACKAGE

(TOP VIEW)

1 2 3 4 5 6 7 8 9 10 11 12 13 14

28 27 26 25 24 23 22 21 20 19 18 17 16 15

D Consumes Less Than 0.5 mW Operating D Drives 4- or 5-Segment LED Display for

Remaining Capacity Indication

D 28-Pin 150-Mil SSOP

description

The bq2063 SBS-compliant gas gauge IC for battery-pack or in-system installation maintains an accurate record of available charge in Li-Ion batteries. The bq2063 monitors capacity and other critical parameters in Li-Ion battery packs. It also directly interfaces the Seiko S-8243 protection IC to minimize component count in smart-battery circuits.

SMBC SMBD SAFETY GND GND VCELL SR1 SR2 SRC TS THON DISP LED5 LED4

The bq2063 uses a V-to-F converter with automatic offset correction for charge and discharge counting. For voltage, temperature, and current reporting, the bq2063 uses an A-to-D converter. In conjunction with the S-8243, the onboard ADC also monitors individual cell voltages in a Li-Ion battery pack and allows the bq2063 to generate control signals to enhance pack safety.

The bq2063 supports the smart battery data (SBData) commands and charge-control functions. It communicates data using the system management bus (SMBus) 2-wire protocol or the 1-wire HDQ16 protocol. The data available include the battery’s remaining capacity, temperature, voltage, current, and remaining run-time predictions. The bq2063 provides LED drivers and a push-button input to depict remaining battery capacity from full to empty in 20% or 25% increments with a 4- or 5-segment display.

The bq2063 works with an external EEPROM. The EEPROM stores the configuration information for the bq2063, such as the battery’s chemistry, self-discharge rate, rate-compensation factors, measurement calibration, and design voltage and capacity . The bq2063 uses the programmable self-discharge rate and other compensation factors stored in the EEPROM to accurately adjust remaining capacity for use and standby conditions based on time, rate, and temperature. The bq2063 also automatically calibrates or learns the true battery capacity in the course of a discharge cycle from programmable near full to near empty levels.

The S-8243 protection IC may be used to provide power to the bq2063 from a 3- or 4-series Li-Ion cell stack.

AVAILABLE OPTIONS

PACKAGE

–20°C to 70°C bq2063DBQ

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

28-LEAD SSOP

(DBQ)

PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters.

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bq2063 SBS v1.1-COMPLIANT Li-ION GAS-GAUGE IC WITH PROTECTOR INTERFACE

SLUS468E– MAY 2001 – REVISED APRIL 2002

Terminal Functions

TERMINAL

NAME No.

CTL2–CTL4 9–11 O 3-state outputs to interface the S-8243 protection IC DISP 17 I Display control for the LED drivers LED1–LED5 ESCL 2 O Serial memory clock for data transfer between the bq2063 and the external nonvolatile configuration memory ESDA 3 I/O Bidirectional pin that transfers address and data to and from the bq2063 and the external nonvolatile

GND 24–25 Must be tied externally to VSS HDQ16 1 I/O Serial communication open-drain bidirectional communications port LED1–LED5 12–16 O LED display segments that each may drive an external LED RBI 4 I Register backup that provides backup potential to the bq2063 registers during periods of low operating

REG 5 O Regular output to control an n-JFET for Vcc regulation to the bq2063 from the battery potential SAFETY 26 O Open-drain output for an additional level of safety protection (e.g., fuse blow) SMBC 28 I/O SMBus clock open-drain bidirectional pin used to clock the data transfer to and from the bq2063 SMBD 27 I/O SMBus data open-drain bidirectional pin used to transfer address and data to and from the bq2063 SRC 20 I Current-sense voltage to monitor instantaneous current SR1–SR2 22–21 I Connections for a small-value sense resistor to monitor the battery charge- and discharge-current flow THON 18 O Control for external FET s to connect the thermistor bias resistor during a temperature measurement TS 19 I Thermistor voltage input connection to monitor temperature VCC 7 I Supply voltage VCELL 23 I Single-cell voltage input that monitors the series element cell voltages from the S-8243 VOUT 6 O VCC output that supplies power to the external EEPROM configuration memory VSS 8 Ground

I/O

configuration memory

voltage. RBI accepts a storage capacitor or a battery input

DESCRIPTION

absolute maximum ratings over operating free-air temperature (unless otherwise noted)

Supply voltage (V Input voltage, V Operating free-air temperature range, T Storage temperature range, T Junction temperature range, T

with respect to VSS) 6 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

, all other pins (all with respect to VSS) 6 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(IN)

STG

–40°C to 125°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

–20°C to 70°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

–20°C to 70°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

†

Lead temperature (soldering, 10 s) 300°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

†

Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

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bq2063

SBS v1.1-COMPLIANT Li-ION GAS-GAUGE IC

WITH PROTECTOR INTERFACE

SLUS468E– MAY 2001 – REVISED APRIL 2002

electrical characteristics for VCC = 2.7 V to 3.7 V, TA = –20°C to 70°C (unless otherwise noted)

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

(SLP)

(LVOUT)VOUT

(VOUT)VOUT

(OLS)

(IL)

(ILS)

(IHS)

(AI)

(RB)

(RBI)

(AI1)

(AI2)

Supply voltage 2.7 3.3 3.7 V Operating current VOUT inactive 180 235 Low-power storage mode current 1.5 V < VCC < 3.7 V 5 10

leakage current VOUT inactive –0.2 0.2 source current

Output voltage low: (LED1–LED5, CTL2–4) I Input voltage low DISP –0.3 0.8 V Input voltage high DISP 2 VCC + 0.3 V Output voltage low SMBC, SMBD, HDQ16, ESCL,

ESDA, THON Input voltage low SMBC, SMBD, HDQ16, ESCL, ESDA –0.3 0.8 V Input voltage high SMBC, SMBD, HDQ16, ESCL, ESDA 1.7 6 V Input voltage range VCELL, TS, SRC VSS – 0.3 1.25 V RBI data-retention input current V RBI data-retention voltage 1.3 V Input impedance SR1, SR2 0 V–1.25 V 10 Input impedance VCELL, TS, SRC 0 V–1.25 V 5

VOUT active, V

= VCC – 0.6 V

OUT

= 5 mA 0.4 V

(OLS)

IOL = 1 mA 0.4 V

> 3 V, VCC < 2 V 10 50 nA

(RBI)

–5 mA

MΩ MΩ

µA µA µA

VFC characteristics, VCC = 3.1 V to 3.5 V, TA= 0°C to 70°C (unless otherwise noted)

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

(SR)

(SROS)

(SRCOS)

VCO

(TCO)

INL Integral nonlinearity error TA = 0°C to 50°C 0.21%

NOTE 1: RM

Input voltage range, V Input offset V Calibrated offset –16 16 Supply voltage gain coefficient VCC = 3.5 V 0.8 1.2 %/V

Temperature gain coefficient (see Note 1)

total deviation is from the nominal VFC gain at 25°C.

(TCO)

(SR2)

and V

(SR1)

VSR = V

(SR2)

Slope for TA = –20°C to 70°C –0.09 0.09 Total Deviation TA = –20°C to 70°C –1.6% 0.1% Slope for TA = –0°C to 50°C Total Deviation TA = –0°C to 50°C –0.6% 0.1%

(SR2)

= V

– V

(SR1)

, autocorrection disabled –250 –50 250

(SR1)

–0.25 0.25 V

–0.05 0.05

REG characteristics (see Note 2)

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

(RO)

REG

NOTE 2: Characteristics for internal bq2063 regulator control. Leave REG pin open when using regulated voltage from S-8243.

REG controlled output voltage REG

(output current)

JFET: R

(on) < 150 Ω

(ds)

(off) ≤ –3 V at 10 µA

(gs)

3.1 3.3 3.5 V 1

µV µV

%/°C

µA

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bq2063 SBS v1.1-COMPLIANT Li-ION GAS-GAUGE IC WITH PROTECTOR INTERFACE

SLUS468E– MAY 2001 – REVISED APRIL 2002

SMBus ac specifications, TA = –20°C to 70°C, 2.7 V < VCC < 3.7 V (unless other noted)

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

SMB

MAS

BUF

HD:STA

SU:STA

SU:STO

HD:DAT

SU:DAT

TIMEOUT

LOW

HIGH

LOW:SEXT

LOW:MEXT

NOTES: 3. The bq2063 times out when any clock low exceeds T

SMBus operating frequency Slave mode, SMBC 50% duty cycle 10 100 kHz SMBus master clock frequency Master mode, no clock low slave extend 51.2 kHz Bus free time between start and stop 4.7 µs Hold time after (repeated) start 4.0 µs Repeated start setup time 4.7 µs Stop setup time 4.0 µs

Data hold time Data setup time 250 µs

Error signal/detect See Note 3 25 35 ms Clock low period 4.7 µs Clock high period See Note 4 4.0 50 µs Cumulative clock low slave extend time See Note 5 25 ms Cumulative clock low master extend time See Note 6 10 ms

4. T

5. T

6. T

Max. is minimum bus idle time. SMBC = SMBD = 1 for t > 50 µs causes reset of any transaction involving bq2063 that is in

HIGH

progress.

LOW:SEXT LOW:MEXT

is the cumulative time a slave device is allowed to extend the clock cycles in one message from initial start to the stop.

is the cumulative time a master device is allowed to extend the clock cycles in one message from initial start to the stop.

Receive mode 0 Transmit mode

TIMEOUT

300

µs

HDQ16 ac specifications, TA = –20°C to 70°C, 2.7 V < VCC < 3.7 V (unless otherwise noted)

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

CYCH

CYCB

STRH

STRB

DSU

DSUB

(DH)

SSU

SSUB

RSPS

Cycle time, host to bq2063 (write) 190 µs Cycle time, bq2063 to host (read) 190 205 250 µs Start hold time, host to bq2063 (write) 5 µs Start hold time, bq2063 to host (read) 32 µs Data setup time 50 µs Data setup time 50 µs Data hold time 100 µs Data valid time 80 µs Stop setup time 145 µs Stop setup time 145 µs Response time, bq2063 to host 190 320 µs Break time 190 µs Break recovery time 40 µs

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Figures 1–4 illustrate the diagrams for the bq2063.

SMBC

HD:STA

SU:STA

SBS v1.1-COMPLIANT Li-ION GAS-GAUGE IC

WITH PROTECTOR INTERFACE

SLUS468E– MAY 2001 – REVISED APRIL 2002

HIGH

LOW

HD:DAT

bq2063

SMBD

STRH

SU:STO

BUF

DSU

SU:DAT

Figure 1. SMBus Timing Data

Figure 2. HDQ16 Break Timing

Write 1

Write 0

SSU

CYCH

STRB

DSUB

Figure 3. HDQ16 Host to bq2063

SSUB

CYCB

Figure 4. HDQ16 bq2063 to Host

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bq2063 SBS v1.1-COMPLIANT Li-ION GAS-GAUGE IC WITH PROTECTOR INTERFACE

SLUS468E– MAY 2001 – REVISED APRIL 2002

functional description

general operation

The bq2063 determines battery capacity by monitoring the amount of charge input or removed from a rechargeable battery. In addition to measuring charge and discharge, the bq2063 measures battery voltage, temperature, and current, estimates battery self-discharge, and monitors the battery for low-voltage thresholds. The bq2063 measures charge and discharge activity by monitoring the voltage across a small-value series sense resistor between the battery’s negative terminal and the negative terminal of the battery pack. The available battery charge is determined by monitoring this voltage and correcting the measurement for environmental and operating conditions.

The bq2063 accepts an NTC thermistor (Semitec 103A T) for temperature measurement or can be configured for internal IC measurement. The bq2063 uses temperature to monitor battery pack and to compensate the self-discharge estimate.

measurements

The bq2063 uses a fully differential, dynamically balanced voltage-to-frequency converter (VFC) for charge measurement and a sigma delta analog-to-digital converter (ADC) for battery voltage, current, and temperature measurement.

Voltage, current, and temperature measurements are made every 2–2.2 seconds, depending on the bq2063 operating mode. Maximum times occur with compensated EDV, mWh mode, and maximum allowable discharge rate. Any AtRate computations requested or scheduled (every 20 seconds) may add up to 0.5 seconds to the time interval.

charge and discharge counting

The VFC measures the charge and discharge flow of the battery by monitoring a small-value sense resistor between the SR1 and SR2 pins as shown in Figure 13. The VFC measures bipolar signals up to 250 mV. The bq2063 detects charge activity when V V

= V

(SR2)–V(SR1)

is negative. The bq2063 continuously integrates the signal over time using an internal

= V

(SR2)–V(SR1)

is positive and discharge activity when

counter. The fundamental rate of the counter is 6.25 µVh.

offset calibration

The bq2063 provides an auto-calibration feature to cancel the voltage offset error across SR

and SR2 for

maximum charge measurement accuracy. The calibration routine is initiated by issuing a command to ManufacturerAccess( ). The bq2063 is capable of automatic offset calibration down to 6.25µV. Offset cancellation resolution is less than 1 µV.

digital filter

The bq2063 does not measure charge or discharge counts below the digital filter threshold. The digital filter threshold is programmed in the EEPROM and should be set sufficiently high to prevent false signal detection with no charge or discharge flowing through the sense resistor.

voltage

While monitoring SR

and SR2 for charge and discharge currents, the bq2063 monitors the battery-pack

potential and the individual cell voltages through the VCELL pin. The bq2063 measures the voltage of three or four series elements in a battery pack. CTL3 and CTL4 signal the S-8243 to present the cell voltages at the VCELL input of the bq2063 according to T able 1 1. The bq2063 calculates the pack voltage and reports the result in Voltage( ). The individual cell voltages are stored in the optional manufacturer function area.

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SBS v1.1-COMPLIANT Li-ION GAS-GAUGE IC

WITH PROTECTOR INTERFACE

SLUS468E– MAY 2001 – REVISED APRIL 2002

functional description (continued)

current

The SRC input of the bq2063 measures battery charge and discharge current. The SRC ADC input converts the current signal from the series sense resistor and stores the result in Current( ). The full-scale input range to SBC is limited to ±250 mV.

temperature

The bq2063 can use its internal sensor or an external thermistor to develop the temperature reading, depending on the programming of the EXTH bit in Pack Configuration, EE 0x3f.

The TS input of the bq2063 in conjunction with an NTC thermistor measures the battery temperature as shown in Figure 13. The bq2063 reports temperature in Temperature( ). THON through the external thermistor when the bq2063 samples the TS input. THON the temperature is measured, and high impedance otherwise.

gas gauge operation

general

The operational overview in Figure 5 illustrates the gas gauge operation of the bq2063. Table 2 describes the bq2063 registers.

may be used to switch the bias current

is low impedance for 60 ms when

bq2063

Inputs

Main Counters and

Capacity Reference (FCC)

Outputs

Charge

Current

Charge

Efficiency

Compensation

Battery Load and Light

Discharge Estimate

– –

– ++

Remaining

Capacity

(RM)

Chip-Controlled

Available Charge

LED Display

≤

Discharge

Current

Full

Charge

Capacity

(FCC)

Temperature, Other Data

Two-Wire

Serial Port

Qualified

Transfer

Self-Discharge

Timer

Temperature

Compensation

Discharge

Count

(DCR)

Figure 5. bq2063 Operational Overview

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bq2063 SBS v1.1-COMPLIANT Li-ION GAS-GAUGE IC WITH PROTECTOR INTERFACE

SLUS468E– MAY 2001 – REVISED APRIL 2002

general (continued)

The bq2063 accumulates a measure of charge and discharge currents and estimates self-discharge of the battery . The bq2063 compensates the charge current measurement for temperature and state-of-charge of the battery. The bq2063 also adjusts the self-discharge estimation based on temperature.

The main charge counter RemainingCapacity( ) (RM) represents the available capacity or energy in the battery at any given time. The bq2063 adjusts RM for charge, self-discharge, and leakage compensation factors. The information in the RM register is accessible through the communications ports and is also represented through the LED display.

The FullChargeCapacity( ) (FCC) register represents the last measured full discharge of the battery. It is used as the battery’s full-charge reference for relative capacity indication. The bq2063 updates FCC after the battery undergoes a qualified discharge from nearly full to a low battery level. FCC is accessible through the serial communications ports.

The Discharge Count Register (DCR) is a non-accessible register that tracks discharge of the battery. The bq2063 uses the DCR register to update the FCC register if the battery undergoes a qualified discharge from nearly full to a low battery level. In this way , the bq2063 learns the true discharge capacity of the battery under system use conditions.

main gas-gauge registers

The gas-gauge register functions are described in Table 2.

RemainingCapacity( ) (RM)

RM represents the remaining capacity in the battery. The bq2063 computes RM in either mAh or 10 mWh depending on the selected mode.

RM counts up during charge to a maximum value of FCC and down during discharge and self-discharge to 0. In addition to charge and self-discharge compensation, the bq2063 calibrates RM at three low-battery-voltage thresholds, EDV2, EDV1, and EDV0 and three programmable midrange thresholds VOC25, VOC50, and VOC75. This provides a voltage-based calibration to the RM counter.

DesignCapacity( ) (DC)

The DC is the user-specified battery full capacity. It is calculated from Pack Capacity EE 0x3a-0x3b and is represented in mAh or 10 mWh. It also represents the full-battery reference for the absolute display mode.

FullChargeCapacity( ) (FCC)

FCC is the last measured discharge capacity of the battery. It is represented in either mAh or 10 mWh, depending on the selected mode. On initialization, the bq2063 sets FCC to the value stored in Last Measured Discharge EE 0x38-0x39. During subsequent discharges, the bq2063 updates FCC with the last measured discharge capacity of the battery . The last measured discharge of the battery is based on the value in the DCR register after a qualified discharge occurs. Once updated, the bq2063 writes the new FCC value to EEPROM in mAh to Last Measured Discharge. FCC represents the full battery reference for the relative display mode and relative state of charge calculations.

discharge count register (DCR)

The DCR register counts up during discharge, independent of RM. DCR can continue to count even after RM has counted down to 0. Before RM = 0, discharge activity , light discharge estimation, battery load estimation, and self-discharge increment DCR. After RM = 0, the bq2063 does not apply self-discharge and DCR increments only because of discharge activity, light discharge estimation, and battery load estimation. The bq2063 initializes DCR, at the beginning of a discharge, to FCC – RM when RM is within twice the programmed value in Near Full EE 0x55. The DCR initial value of FCC – RM is reduced by FCC/128 if SC = 0 (bit 2 in Control Mode) and is not reduced if SC = 1. DCR stops counting when the battery voltage reaches the EDV2 threshold on discharge.

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SBS v1.1-COMPLIANT Li-ION GAS-GAUGE IC

WITH PROTECTOR INTERFACE

SLUS468E– MAY 2001 – REVISED APRIL 2002

gas gauge operation (continued)

capacity learning (FCC update) and qualified discharge

The bq2063 updates FCC with an amount based on the value in DCR if a qualified discharge occurs. The new value for FCC equals the DCR value plus the programmable nearly full and low battery levels, according to the following equation:

bq2063

FCC (new) + DCR (final) + DCR (initial) ) Measured Discharge to EDV2) (FCC Battery Low%)

Battery Low % = (value stored in EE 0x54) ÷ 2.56

A qualified discharge occurs if the battery discharges from RM ≥ FCC – Near Full × 2 to the EDV2 voltage threshold with the following conditions:

(1)

D No valid charge activity occurs during the discharge period. A valid charge is defined as a charge of 10 mAh

into the battery.

D No more than 256 mAh of self-discharge, battery load estimation, and/or light discharge estimation occurs

during the discharge period.

D The temperature does not drop below the low temperature thresholds programmed in Max T_LowT or 12°C

during the discharge period. The threshold depends on the programming of the LLTF bit in Pack Programming, EE 0x63.

D The battery voltage reaches the EDV2 threshold during the discharge period and the voltage was less than

the EDV2 threshold minus 256 mV when the bq2063 detected EDV2.

D No midrange voltage correction occurs during the discharge period. D Current remains ≥ 3C/32 or C/32, depending on Pack Programming selection, when EDV2 or Battery Low

% level is reached.

The bq2063 sets VDQ=1 in Pack Status when qualified discharge begins. The bq2063 sets VDQ=0 if any disqualifying condition occurs. FCC cannot be reduced by more than 256 mAh or increased by more than 512 mAh during any single update cycle. The bq2063 saves the new FCC value to the EEPROM within 4 seconds of being updated.

end-of-discharge thresholds and capacity correction

The bq2063 monitors the battery for three low-voltage thresholds, EDV0, EDV1, and EDV2. The EDV thresholds can be programmed for determination based on the overall pack voltage or an individual cell level. The EDVV bit in Pack Programming configures the bq2063 for overall voltage or single-cell EDV thresholds. If programmed for single cell EDV determination, the bq2063 determines EDV on the basis of the lowest single-cell voltage. Fixed EDV thresholds may be programmed in EDVF/EDV0 EE 0x72-0x73, EMF/EDV1 EE 0x74-0x75, and EDV C0 Factor/EDV2 EE 0x78-0x79. If the CEDV bit in Pack Configuration is set, automatic EDV compensation is enabled and the bq2063 computes the EDV0, EDV1, and EDV2 thresholds based on the values in EE 0x72-0x7d, 0x06, and the battery’s current discharge rate and temperature. The bq2063 disables EDV detection if Current( ) exceeds the Overload Current threshold programmed in EE 0x46 – EE 0x47. The bq2063 resumes EDV threshold detection after Current( ) drops below the overload current threshold. Any EDV threshold detected is reset after 10 mAh of charge are applied.

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bq2063

ACCESS

SBS v1.1-COMPLIANT Li-ION GAS-GAUGE IC WITH PROTECTOR INTERFACE

SLUS468E– MAY 2001 – REVISED APRIL 2002

end-of-discharge thresholds and capacity correction (continued)

Table 1. State of Charge Based on Low Battery V oltage

THRESHOLD RELATIVE STATE

EDV0 0% EDV1 3% EDV2 Battery Low %

OF CHARGE

The bq2063 uses the EDV thresholds to apply voltage-based corrections to the RM register according to Table 1. The bq2063 performs EDV-based RM adjustments with Current( ) ≥ C/32. No EDVs are set if current < C/32. The bq2063 adjusts RM as it detects each threshold. If the voltage threshold is reached before the corresponding capacity on discharge, the bq2063 reduces RM to the appropriate amount as shown in T able 1. This reduction occurs only if current ≥ C/32 when the EDV threshold is detected. If RM reaches the capacity level before the voltage threshold is reached on discharge, the bq2063 prevents RM from decreasing further until the battery voltage reaches the corresponding threshold only on a full learning cycle discharge. RM is not held at the associated EDV percentage on a nonlearning discharge cycle (VDQ=0) or if current < C/32.

Table 2. bq2063 Register Functions

FUNCTION

ManufacturerAccess 0x00 0x00 read/write NA RemainingCapacityAlarm 0x01 0x01 read/write mAh, 10 mWh RemainingTimeAlarm 0x02 0x02 read/write minutes BatteryMode 0x03 0x03 read/write NA AtRate 0x04 0x04 read/write mA, 10mW AtRateTimeToFull 0x05 0x05 read minutes AtRateTimeToEmpty 0x06 0x06 read minutes AtRateOK 0x07 0x07 read Boolean Temperature 0x08 0x08 read 0.1°K Voltage 0x09 0x09 read mV Current 0x0a 0x0a read mA AverageCurrent 0x0b 0x0b read mA MaxError 0x0c 0x0c read percent RelativeStateOfCharge 0x0d 0x0d read percent AbsoluteStateOfCharge 0x0e 0x0e read percent RemainingCapacity 0x0f 0x0f read mAh, 10 mWh FullChargeCapacity 0x10 0x10 read mAh, 10 mWh RunTimeToEmpty 0x11 0x11 read minutes AverageTimeToEmpty 0x12 0x12 read minutes AverageTimeToFull 0x13 0x13 read minutes ChargingCurrent 0x14 0x14 read mA ChargingVoltage 0x15 0x15 read mV Battery Status 0x16 0x16 read NA CycleCount 0x17 0x17 read cycles DesignCapacity 0x18 0x18 read mAh, 10 mWh DesignVoltage 0x19 0x19 read mV SpecificationInfo 0x1a 0x1a read NA ManufactureDate 0x1b 0x1b read NA

COMMAND CODE

SMBus HDQ16

ACCESS (SMBus)

UNITS

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SBS v1.1-COMPLIANT Li-ION GAS-GAUGE IC

ACCESS

WITH PROTECTOR INTERFACE

SLUS468E– MAY 2001 – REVISED APRIL 2002

Table 2. bq2063 Register Functions (Continued)

bq2063

FUNCTION

SerialNumber 0x1c 0x1c read integer Reserved 0x1d-0x1f 0x1d–0x1f — — ManufacturerName 0x20 0x20–0x25 read string DeviceName 0x21 0x28–0x2b read string DeviceChemistry 0x22 0x30–0x32 read string ManufacturerData 0x23 0x38–0x3b read string Pack Status 0x2f (LSB) 0x2f (LSB) read/write NA Pack Configuration 0x2f (MSB) 0x2f (MSB) read/write NA VCELL4 0x3c 0x3c read/write mV VCELL3 0x3d 0x3d read/write mV VCELL2 0x3e 0x3e read/write mV VCELL1 0x3f 0x3f read/write mV

COMMAND CODE

SMBus HDQ16

ACCESS (SMBus)

UNITS

self-discharge

The bq2063 estimates the self-discharge of the battery to maintain an accurate measure of the battery capacity during periods of inactivity. The algorithm for self-discharge estimation takes a programmed estimate for the expected self-discharge rate at 25°C stored in EEPROM and makes a fixed reduction to RM of an amount equal to RemainingCapacity( )/256. The bq2063 makes the fixed reduction at a varying time interval that is adjusted to achieve the desired self-discharge rate. This method maintains a constant granularity of 0.39% for each self-discharge adjustment, which may be performed multiple times per day, instead of once per day with a potentially large reduction.

The self-discharge estimation rate for 25°C is doubled for each 10 degrees above 25°C or halved for each 10 degrees below 25°C. The following table shows the relation of the self-discharge estimation at a given temperature to the rate programmed for 25°C (Y% per day).

Table 3. Self-Discharge for Rate Programmed

TEMPERATURE

(°C)

Temp < 10 1/4 Y% per day 10 ≤ Temp <20 1/2 Y% per day 20 ≤ Temp <30 Y% per day 30 ≤ Temp <40 2Y% per day 40 ≤ Temp <50 4Y% per day 50 ≤ Temp <60 8Y% per day 60 ≤ Temp <70 16Y% per day

70≤ Temp 32Y% per day

SELF-DISCHARGE RATE

The interval at which RM is reduced is given by the following equation, where n is the appropriate factor of 2 (n = 1/4, 1/2,1, 2, . . . ):

Self-Discharge Update Time +

640 • 13500

256 • n • (Y% per day)

seconds

(2)

Example: If T = 35°C (n = 2) and programmed self-discharge rate Y is 2.5% per day at 25°C, the bq2063 reduces RM by RM/256 (0.39%) every

640 • 13500

256 • 2 • 2.5

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+ 6750 seconds

(3)

bq2063 SBS v1.1-COMPLIANT Li-ION GAS-GAUGE IC WITH PROTECTOR INTERFACE

SLUS468E– MAY 2001 – REVISED APRIL 2002

self-discharge (continued)

The timer that keeps track of the self-discharge update time is halted whenever charge activity is detected. The timer is reset to zero if the bq2063 reaches the RemainingCapacity( )=FullChargeCapacity() condition while charging.

CAPACITY

TIME

1200

1000

800

TA = 15°C

600

TA = 25°C

Capacity – mAh

400

TA = 35°C

200

TA = 45°C

0 10203040506070

Time – Days

Figure 6. Self-Discharge at 2.5%/Day at 25°C

This means that a 0.39% reduction of RM is made 12.8 times per day to achieve the desired 5% per day reduction at 35°C.

Figure 6 illustrates how the self-discharge estimate algorithm adjusts RemainingCapacity( ) vs temperature.

light discharge or suspend current compensation

The bq2063 can be configured in two ways to compensate for small discharge currents that produce a signal below the digital filter. First, the bq2063 can decrement RM and DCR at a rate determined by the value stored in Light Discharge Current EE 0x64 when it detects no discharge activity and the SMBC and SMBD lines are high. Light Discharge Current has a range of 0 mA to 11.2 mA, with 44 µA granularity.

Alternatively , the bq2063 can be configured to disable the digital filter for discharge when the SMBC and SMBD lines are high. In this way , the digital filter does not mask the leakage-current signal. The bq2063 is configured in this mode by setting the NDF bit in Control Mode.

battery electronic load compensation

The bq2063 can be configured to compensate for a constant load present in the battery pack at all times, such as from battery electronics. The bq2063 applies the compensation continuously when the charge or discharge is below the digital filter. The bq2063 applies the compensation in addition to self-discharge. The compensation occurs at a rate determined by the value stored in Pack Load Estimate EE 0x1c. The compensation range is 0 µA–700 µA in steps of approximately 2.75 µA.

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SBS v1.1-COMPLIANT Li-ION GAS-GAUGE IC

WITH PROTECTOR INTERFACE

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midrange capacity corrections

The bq2063 applies midrange capacity corrections when the VCOR bit is set in Pack Configuration. The bq2063 adjusts RM to the associated percentage at three different voltage levels: VOC25, VOC50, and VOC75. The VOC values represent the open circuit battery voltage at which RM corresponds to the associated for each threshold.

For the midrange corrections to occur, the temperature must be in the range of 19°C to 31°C inclusive and the Current( ) and AverageCurrent( ) must both be between –64 mA and 0. The bq2063 makes midrange corrections as shown in T able 4. For a correction to occur , the bq2063 must detect the need for correction twice during subsequent 20-s intervals. With the VCOR bit set, the bq2063 makes mid-range corrections whenever conditions permit. If the OTVC bit in Pack Configuration is set and VCOR = 0, the bq2063 makes a single attempt of mid-range correction immediately after device reset and does not require a second validation. The OTVC bit read by command code 0x2f is cleared within 2 seconds after a device reset, when the midrange voltage correction attempt is made.

Table 4. Midrange Corrections

CONDITION RESULT

Voltage() ≥ VOC75 and RelativeStateOfCharge( ) ≤ 63% RelativeStateOfCharge( )→75%

< VOC75 and RelativeStateOfCharge( ) ≥ 87% RelativeStateOfCharge( )→75% ≥VOC50 and RelativeStateOfCharge( ) ≤ 38% RelativeStateOfCharge()→50% <VOC50 and RelativeStateOfCharge( ) ≥ 62% RelativeStateOfCharge( )→50% ≥ VOC25 and RelativeStateOfCharge( ) ≤ 13% RelativeStateOfCharge( )→25% < VOC25 and RelativeStateOfCharge( ) ≥ 37% RelativeStateOfCharge( )→25%

bq2063

charge control

charging voltage and current broadcasts

The bq2063 supports SBS charge control by broadcasting the ChargingCurrent( ) and ChargingVoltage( ) to the Smart Charger address. The bq2063 broadcasts the requests every 10 seconds. The bq2063 updates the values used in the charging current and voltage broadcasts based on the battery’s state of charge, voltage, and temperature. The charge voltage is programmed in Charging Voltage EE 0x0a-0x0b. The charge current may take any of four different values and depends on charge state and operating conditions.

The bq2063 internal charge control is compatible with the constant current/constant voltage profile for Li-Ion. The bq2063 detects primary charge termination on the basis of the tapering charge current during the constant-voltage phase.

alarm broadcasts to smart charger and host

If any of the bits 8–15 in BatteryStatus( ) are set, the bq2063 broadcasts an AlarmWarning( ) message to the Host address. If any of the bits 12–15 in BatteryStatus( ) are set, the bq2063 also sends an AlarmWarning( ) message to the Smart Charger address. The bq2063 repeats the AlarmWarning( ) messages every 10 seconds until the alarm bits are cleared.

precharge qualification

The bq2063 sets ChargingCurrent( ) to the precharge rate as programmed in Pre-charge Current EE 0x1e under the following conditions:

D Voltage: The bq2063 requests the precharge charge rate when Voltage( ) or the lowest cell voltage drops

below the EDVF threshold or when the EDV0 threshold is detected. Once requested, a precharge rate remains until Voltage( ) or the lowest cell voltage increases above the EDVF threshold. The EDVF threshold is programmed in EDVF/ EDV0 EE 0x72-0x73.

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D Temperature: The bq2063 requests the precharge rate when Temperature( ) is between 0°C and the low

temperature fault (L TF) threshold programmed in MaxT_LowT. T emperature( ) must be equal to or greater than the L TF threshold to allow the fast-charge rate. The L TF threshold is programmed in the lower nibble of MaxT_LowT EE 0x45.

charge suspension

The bq2063 may temporarily suspend charge if it detects a charging fault. A charging fault includes the following conditions.

D Overcurrent: An overcurrent condition exists when the bq2063 measures the charge current to be more

than Overcurrent Margin plus ChargingCurrent( ). Overcurrent Margin is programmed in EE 0x49. On detecting an overcurrent condition, the bq2063 sets the ChargingCurrent( ) to zero and sets the TERMINATE_CHARGE_ALARM bit in Battery Status( ). The overcurrent condition and TERMINA TE_CHARGE_ALARM are cleared when the measured current drops below Overcurrent Margin.

D Overvoltage: An overvoltage condition exists when the bq2063 measures the battery voltage to be more

than Overvoltage Margin plus ChargingVoltage( ), or when a Li-Ion cell voltage has exceeded the overvoltage limit programmed in Cell Under/Overvoltage. Overvoltage Margin is programmed in EE 0x48 and Cell Under/Over Voltage in EE 0x4a. On detecting an overvoltage condition, the bq2063 sets the ChargingCurrent( ) to zero and sets the TERMINATE_CHARGE_ALARM bit in BatteryStatus( ). The bq2063 clears the TERMINA TE_ CHARGE_ALARM bit when it detects that the battery is no longer being charged (DISCHARGING bit set in BatteryStatus( )). The bq2063 continues to broadcast zero charging current until the overvoltage condition is cleared. The overvoltage condition is cleared when the measured battery voltage drops below the ChargingVoltage( ) plus the Overvoltage Margin and all cell voltages are less than the Cell Under/Over Voltage threshold.

D Overtemperature: An overtemperature condition exists when T emperature( ) is greater than or equal to the

Max T value programmed in EE 0x45 (MSN). On detecting an overtemperature condition, the bq2063 sets the ChargingCurrent( ) to zero and sets the OVER_TEMP_ALARM and TERMINATE_CHARGE_ ALARM bit in BatteryStatus( ) and the CVOV bit in Pack Status. The overtemperature condition is cleared when Temperature( ) is equal to or below (MaxT –5°C) or 43°C.

D Overcharge: An overcharge condition exists if the battery is charged more than the Maximum Overcharge

value after RM = FCC. Maximum Overcharge is programmed in EE 0x2e-0x2f. On detecting an overcharge condition, the bq2063 sets the ChargingCurrent( ) to zero and sets the OVER_CHARGED_ALARM, TERMINA TE_CHARGE_ ALARM, and FULLY_CHARGED bits in BatteryStatus( ). The bq2063 clears the OVER_ CHARGED_ALARM and TERMINATE_CHARGE_ ALARM when it detects that the battery is no longer being charged. The FULL Y_CHARGED bit remains set and the bq2063 continues to broadcast zero charging current until RelativeStateOfCharge( ) is less than Fully Charged Clear% programmed in EE 0x4c. The counter used to track overcharge capacity is reset with 2 mAh of discharge.

D Undertemperature: An undertemperature condition exists if Temperature( ) < 0°C. On detecting an under

temperature condition, the bq2063 sets ChargingCurrent( ) to zero. The bq2063 sets ChargingCurrent( ) to the appropriate precharge rate or fast-charge rate when Temperature( ) ≥ 0°C.

primary charge termination

The bq2063 terminates charge if it detects a charge-termination condition based on current taper. A charge-termination condition includes the following:

For current taper, ChargingVoltage( ) must be set to the pack voltage desired during the constant-voltage phase of charging. The bq2063 detects a current taper termination when the pack voltage is greater than ChargingVoltage( ) minus Current Taper Qual Voltage in EE 0x4f and the charging current is below a threshold determined by Current T aper Threshold in EE 0x4e, for at least 40 seconds. The bq2063 uses the VFC to measure current for current taper termination. The current must also remain above 0.5625/Rs mA to qualify the termination condition.

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primary charge termination (continued)

Ca acity added after RM( ) = FCC( ) ≥

Primary charge

Once the bq2063 detects a primary charge termination, the bq2063 sets the TERMINATE_CHARGE_ALARM and FULLY_CHARGED bits in BatteryStatus( ), and sets the ChargingCurrent( ) to the maintenance charge rate as programmed in Maintenance Charging Current EE 0x1d. On termination, the bq2063 also sets RM to a programmed percentage of FCC, provided that RelativeStateOfCharge( ) is below the desired percentage of FCC and the CSYNC bit in Pack Configuration EE 0x3f is set. The programmed percentage of FCC, Fast Charge Termination %, is set in EE 0x4b. The bq2063 clears the FULLY_CHARGED bit when RelativeStateOfCharge( ) is less than the programmed Fully Charged Clear %. The bq2063 broadcasts the fast-charge rate when the FULLY_CHARGED bit is cleared and voltage and temperature permit. The bq2063 clears the TERMINATE_CHARGE_ALARM when it no longer detects that the battery is being charged or it no longer detects the termination condition. See Table 5 for a summary of BatteryStatus( ) alarm and status bit operation.

Table 5. Alarm and Status Bit Summary

bq2063

SBS v1.1-COMPLIANT Li-ION GAS-GAUGE IC

WITH PROTECTOR INTERFACE

SLUS468E– MAY 2001 – REVISED APRIL 2002

BATTERY STATE CONDITIONS

Overcurrent C( ) ≥ CC( ) + Overcurrent Margin CC( ) = 0, TCA = 1 C( ) < Overcurrent Margin Prolonged

overcurrent Overload AC( ) ≤ –Overload Current CVUV = 1 AC( ) ≥ –256 mA

Overvoltage

Overtemperature T( ) ≥ Max T

Overcharge

Undertemperature

Primary charge termination

Fully discharged

Overdischarged

Low capacity RM( ) < RCA( ) RCA = 1 RM( ) ≥ RCA( ) Low run time ATTE() < RTA( ) RTA = 1 ATTE( ) ≥ RTA()

NOTE: AC( ) = AverageCurrent( ), C( ) = Current( ), CV( ) = ChargingVoltage( ), CC( ) = ChargingCurrent( ), V( ) = Voltage(),

T( ) = Temperature( ), TCA = TERMINATE_CHARGE_ALARM, OTA = OVER_TEMPERATURE_ALARM, OCA = OVER_CHARGED_ALARM, TDA = TERMINATE_DISCHARGE_ALARM, FC = FULLY_CHARGED, FD = FULLY_DISCHARGED, RSOC() = RelativeStateOfCharge( ). RM( ) = RemainingCapacity( ), RCA = REMAINING_CAPACITY_ALARM, RTA = REMAINING_TIME_ALARM, ATTE( ) = AverageTimeToEmpty( ), RTA( ) = RemainingTimeAlarm( ), RCA( ) = RemainingCapacityAlarm( ). LTF = Low Temperature Fault threshold FCC( ) = Full Charge Capacity

AC( ) ≥ Fast-Charging Current +

Overcurrent Margin

V( ) ≥ CV( ) + Overvoltage Margin VCELL1, 2, 3, or 4 ≥ Cell Over Voltage

Capacity added after RM( ) = FCC( ) ≥

Maximum Overcharge

T( ) < 0°C CC( ) = 0 0°C ≤ T( ) 0°C ≤ T( ) < LTF CC( ) = Pre-Charge Current T( ) ≥ LTF

Current taper

RM( ) < Battery Low % and DISCHARGING = 1

RM( ) = 0 V( ) or VCELL1, 2, 3, or 4 ≤ EDV0

VCELL1, 2, 3 or 4 < Cell Under Voltage TDA = 1, CVUV = 1

CC( ) CURRENT AND

STATUS BITS SET

CVOV = 1 CC( ) = 0, TCA = 1

TCA = 1 DISCHARGING = 1 CC( ) = 0, CVOV = 1 CC( ) = 0, OTA = 1,

TCA = 1, CVOV = 1 CC( ) = 0, FC = 1 RSOC( )< Fully Charged Clear % OCA = 1, TCA = 1 DISCHARGING = 1

FC = 1

CC( ) = Maintenance Charging Current

FD = 1 RSOC( ) ≥ 20%

TDA = 1 V( ) or VCELL(all) > EDV0 and RM( ) > 0

STATUS CLEAR CONDITION

AC( ) < 256 mA

V( ) < CV( ) + Overvoltage Margin VCELL(all) ≤ Cell Over Voltage

T( ) ≤ Max T - 5°C or T( ) ≤ 43°C

RSOC( ) < Fully Charged Clear%

V( ) > EDV0 VCELL(all) ≥ Cell Under Voltage

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bq2063 SBS v1.1-COMPLIANT Li-ION GAS-GAUGE IC WITH PROTECTOR INTERFACE

SLUS468E– MAY 2001 – REVISED APRIL 2002

display port

general

The display port drives a 4 or 5 LED bar-graph display. The display is activated by a logic signal on the DISP input. The bq2063 can display RM in either a relative or absolute mode with each LED representing a percentage of the full-battery reference. In relative mode, the bq2063 uses FCC as the full-battery reference; in absolute mode, it uses dc.

The DMODE bit in Pack Configuration programs the bq2063 for the absolute or relative display mode. The LED bit in Control Mode programs the 4- or 5-LED option. A fifth LED can be used with the 4-LED display option to show when the battery capacity is ≥100%.

activation

The display may be activated at any time by a high-to-low transition on the DISP

input. This is usually accomplished with a pullup resistor and a pushbutton switch. Detection of the transition activates the display and starts a four second display timer. Reactivation of the display requires that the DISP

input return to a logic-high state and then transition low again. The second high-to-low transition must occur after the display timer expires. The bq2063 requires the input to remain stable for a minimum of 250 ms to detect the logic state. If unused, the DISP

input must be pulled up to VCC.

If the EDV0 bit is set, the bq2063 disables the LED display . The display is also disabled during a VFC calibration and should be turned off before entering low-power storage mode.

display modes

In relative mode, each LED output represents 20% or 25% of the RelativeStateOfCharge( ) value. In absolute mode, each LED output represents 20% or 25% of the AbsoluteStateOfCharge( ) value. Table 6 shows the display options for 5 LEDs and Table 7 for 4 LEDs.

In either mode, the bq2063 blinks the LED display if RemainingCapacity( ) is less than Remaining CapacityAlarm( ). The display is disabled if EDV0 = 1.

Table 6. Display Mode for Five LEDs

CONDITION RELATIVE

OR ABSOLUTE

StateOfCharge( )

EDV0 = 1 OFF OFF OFF OFF OFF

<20%

≥20%, < 40% ≥40%, < 60% ≥60%, < 80%

≥80%

FIVE LED DISPLAY OPTION

LED1LED

ON OFF OFF OFF OFF ON ON OFF OFF OFF ON ON ON OFF OFF ON ON ON ON OFF ON ON ON ON ON

LED3LED4LED

Table 7. Display Mode for Four LEDs

CONDITION RELATIVE

OR ABSOLUTE

StateOfCharge( )

EDV0 = 1 OFF OFF OFF OFF

<25%

≥25%, < 50% ≥50%, < 75%

≥75%

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FOUR LED DISPLAY OPTION

LED1 LED2 LED3 LED4

ON OFF OFF OFF ON ON OFF OFF ON ON ON OFF ON ON ON ON

SBS v1.1-COMPLIANT Li-ION GAS-GAUGE IC

WITH PROTECTOR INTERFACE

SLUS468E– MAY 2001 – REVISED APRIL 2002

Li-Ion protector control

The bq2063 provides a secondary level of protection for lithium Ion batteries, as shown in T able 8. The bq2063 uses the CTL2 output to communicate battery conditions to the S-8243A/B Protector IC. When the CVOV or CVUV condition occurs the bq2063 changes the state of the CTL2 pin according to Table 8.

The cell overvoltage threshold should be set higher than the overvoltage threshold of the S-8243 protector, establishing a secondary overvoltage protection limit. The cell undervoltage threshold should be set somewhat higher than the overdischarged threshold of the S-8243 protector, establishing the primary undervoltage limit. There is no secondary undervoltage limit if the cell undervoltage threshold is set lower, because the S-8243 goes into a power-down mode and removes V also recommended that the bq2063 protection control be validated by two successive measurements by setting PDLY=1 in Pack Programming.

The bq2063 asserts CVOV to turn off the charge FET if cell overvoltage, battery overvoltage, or overtemperature conditions exist, or if AverageCurrent( ) ≥ Fast-Charging Current + Overcurrent Margin (Prolonged Overcurrent condition in Table 5). It returns control to the S-8243 when overvoltage and overtemperature conditions no longer exist, AverageCurrent( ) < 256 mA (if Prolonged Current generated the fault condition), or Current( ) < 0.

The bq2063 asserts CVUV to turn off the discharge FET if a cell undervoltage condition exists, or if AverageCurrent( ) ≤ –Overload current (Overload). It returns control to the S–8243 when the undervoltage condition no longer exists and AverageCurrent( ) ≥ –256mA (if Overload generated the fault condition), or Current( ) > 0.

to the bq2063 when it detects the overdischarged limit. It is

bq2063

Table 8. bq2063 to S-8243A/B Interface (FET Protection Control)

Battery State (Table 5)

CVOV = 1: Prolonged Overcurrent, Overvoltage, Overtemperature High Normal (see Note) Off CVOV = CVUV = 0 Open Normal (see Note) Normal (see Note) CVUV = 1: Overload, Overdischarged Low Off Normal (see Note)

NOTE: State determined by S-8243A/B

OUTPUT INSTRUCTION TO S-8243A/B (CTL1 = LOW)

CTL2 DISCHARGING FET CHARGING FET

SAFETY output

The SAFETY

output of the bq2063 provides an additional level of safety control. The active low safety output can be used to blow fuse or control another switch based on temperature or a programmable pack-voltage level. The safety temperature threshold is programmable in Safety Overtemperature in EE 0x08 and the voltage level is programmable in Safety Overvoltage in EE 0x1f. The bq2063 SAFETY

is allowed to go low only after the CVOV bit is set 2 seconds before either Voltage( ) > Safety Overvoltage or Temperature( ) ≥ Safety Overtemperature. If the SAFETY

output activates, the bq2063 sets the SOV bit in Pack Status. SOV remains

set until the bq2063 is reset or the bit is overwritten. An example circuit using the SAFETY

output to blow a fuse is shown in Figure 7.

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bq2063 SBS v1.1-COMPLIANT Li-ION GAS-GAUGE IC WITH PROTECTOR INTERFACE

SLUS468E– MAY 2001 – REVISED APRIL 2002

SAFETY output (continued)

FUSE

BAT+

SAFETY

1 MΩ

100 kΩ

Cell 4

0.1 µF

BSS84

2N7002

1 MΩ

Figure 7. Example SAFETY Circuit Implementation

low-power storage mode

The bq2063 enters low-power mode 5-8 seconds after receiving the Enable Low-Power command. In this mode the bq2063 consumes less than 10 µA. A rising edge on SMBC, SMBD, or HDQ16 restores the bq2063 to the full operating mode. The bq2063 does not perform any gas-gauge functions during low-power storage mode.

device reset

The bq2063 can be reset with commands over the HDQ16 or SMBus. Upon reset, the bq2063 initializes its internal registers with the information contained in the configuration EEPROM. The following command sequence initiates a full bq2063 reset:

1. Write 0x005a to address 0x4f

2. Write 0x0000 to address 0x7d

3. Write 0x0080 to address 0x7d A partial reset of the bq2063 occurs if step one is omitted. All initial program values are read from EEPROM

for both full and partial resets. A full reset initializes MaxError( ) = 100%, sets RELEARN FLAG (bit 7) in BatteryMode, and initializes RM from EEPROM 0x2c–2d . This initial RM value should be programmed to zero for secondary (rechargeable) batteries. A partial reset leaves MaxError( ), RELEARN_FLAG, and RM unchanged.

communication

The bq2063 includes two types of communication ports: SMBus and HDQ16. The SMBus interface is a 2-wire bidirectional protocol using the SMBC (clock) and SMBD (data) pins. The HDQ16 interface is a 1-wire bidirectional protocol using the HDQ16 pin. All three communication lines are isolated from VCC and may be pulled-up higher than V should be pulled down with a 100-kΩ resistor, or may be grounded, if not used.

The communication ports allow a host controller, an SMBus compatible device, or other processor to access the memory registers of the bq2063. In this way a system can efficiently monitor and manage the battery.

SMBus

The SMBus interface is a command-based protocol. A processor acting as the bus master initiates communication to the bq2063 by generating a ST ART condition. A ST ART condition consists of a high-to-low transition of the SMBD line while the SMBC is high. The processor then sends the bq2063 device address of

. Also, the bq2063 does not pull these lines low if VCC to the part is zero . HDQ16

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