BQ29311PW

 www.ti.com SLUS487D − DECEMBER 2001 − REVISED NOVEMBER 2003                 FEATURES D 3- or 4-Cell Series Protection Control D Autonomous Overcurrent and Short Circuit Protection D Provides Individual Cell Voltages to Battery Management Host D Integrated Cell Balancing Control D I2C Compatible User Interface Allows Access to Battery Information D User Control to Initiate Protection D Integrated 3.3-V 25-mA LDO D Programmable Shutdown and Brownout Control D Provides Drive for Three External FETs D Low Supply Current of 140 µA Typical D Programmable Threshold and Delay for Short-Circuit Current Protection D Provides Drive for Three External FETs D Can Directly Interface With bq2083/5 for Complete Battery Management Solution DESCRIPTION The bq29311 is a three- or four-cell lithium-ion battery pack protection analog front end (AFE) IC that incorporates a 3.3-V 25-mA low-dropout regulator (LDO) and an I2C compatible interface to extract battery parameters such as cell voltages and control output status. Other parameters, such as overcurrent protection threshold and delay, can also be programmed into the bq29311 to increase the flexibility of the battery management system. The bq29311 provides safety protection in overcurrent, short circuit, overvoltage, and undervoltage conditions via control from the battery management host. In overcurrent and short-circuit conditions the bq29311 can directly activate the FET drive as a secondary protection level. The communications interface allows the host to control and observe the current status of the protection, to set overcurrent and overload levels, to set the overcurrent and overload blanking delay time, short-circuit threshold levels, and short-circuit blanking delay time, and to program for the VREG shutdown voltage and brownout-detection thresholds. APPLICATIONS D Notebook Computer Battery Packs D Test Equipment Each cell is balanced by a discharge path, which is enabled by the internal control registers accessible through the I2C compatible interface. The maximum current is set by an external series resistor with an absolute maximum value of 10 mA discharge current per cell. PIN ASSIGNMENTS ORDERING INFORMATION PW PACKAGE (TOP VIEW) VCC VBAT VC1 VC2 VC3 VC4 VC5 SR1 SR2 CNTL GND VCELL 1 2 3 4 5 6 7 8 9 10 11 12 TA 24 23 22 21 20 19 18 17 16 15 14 13 VPACK DSG PCHG CHG LEDOUT VREG TOUT XALERT CLKIN SDATA SCLK GND −25°C to 85°C PACKAGED TSSOP (PW) bq29311PW bq29311PWR(1) (1) R suffix indicates tape and reel. 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.    ! " #$%! "  &$
'#! (!%) ($#!" # ! "&%##!" &% !*% !%"  %+" "!$%!" "!(( ,!-) ($#! &#%"". (%" ! %#%""'- #'$(% !%"!.  '' &%!%") Copyright  2001 − 2003, Texas Instruments Incorporated 
 www.ti.com SLUS487D − DECEMBER 2001 − REVISED NOVEMBER 2003 These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. PACKAGE DISSIPATION RATINGS PACKAGE TA ≤ 25°C POWER RATING PW 874 mW DERATING FACTOR ABOVE TA = 25°C 6.99 W/°C TA = 70°C POWER RATING TA = 85°C POWER RATING 559 mW 454 mW ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range unless otherwise noted(1) bq29311 Supply voltage range(2) VCC, VPACK VC1, VC2, VC3, VC4, VBAT −0.3 V to 34 V −0.3 V to 34 V VC5, SR1, SR2 Input voltage range −1 V to 1 V VC1 to VC2, VC2 to VC3, VC3 to VC4, VC4 to VC5 −0.3 V to 8.5 V CLK-IN, SCLK, SDATA Output voltage range −0.3 V to 7 V CNTL −0.3 V to 34 V DSG, CHG, PCHG −0.3 V to VCC LEDOUT, TOUT, SCLK, SDATA, VCELL, XALERT −0.3 V to 7 V Current for cell balancing 10 mA Continuous total power dissipation ESD rating(3) See Dissipation Rating Table HBM 1.5 kV CDM 250 V MM 50 V Operating free-air temperature range, TA −25°C to 85°C Storage temperature range, Tstg −65°C to 150°C Lead temperature (soldering, 10 s) 260°C (1) 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. (2) All voltages are with respect to ground of this device except VCn-VC(n+1), where n = 1, 2, 3, 4 cell voltage. (3) Design considerations should be made with respect to excessive ESD. RECOMMENDED OPERATING CONDITIONS MIN NOM Supply voltage (VCC or VPACK) VBAT VC1, VC2, VC3, VC4 SR1, SR2, VC5 Input voltage range, VI VCn−VC(n+1), (n = 1, 2, 3, 4 ) 0 Output current, IO VIH VIL SCLK, SDATA, CLK−IN 0 −0.5 0.5 0 5 0.8×VREG VREG 0 0.2×VREG 200 50 VCELL ± 10 CNTL VREG V VREG SDATA External 3.3-V VREG capacitor, C(REG) 2 V XALERT Input current, II Operating ambient temperature range, TA UNIT 25 VCC VCC CNTL Logic level input voltage MAX −0.5 1 µA µA µF 1 −25 V 85 °C 
 www.ti.com SLUS487D − DECEMBER 2001 − REVISED NOVEMBER 2003 ELECTRICAL CHARACTERISTICS TA = 25°C, CREG = 1 µF, VCC = 14 V (unless otherwise noted) SUPPLY CURRENT PARAMETER I(CC1) Supply current 1 I(CC2) Supply current 2 TEST CONDITIONS No load at VREG, TOUT, LEDOUT, XALERT, SCLK, SDATA. CLKIN not used VBAT ≤ VSD, VPACK = 0 DSG, CHG and PCHG = off MIN TA = 25°C TYP MAX 140 190 TA = − 25°C to 85°C 220 TA = − 25°C to 85°C 1 UNIT µA µA 3.3 V REGULATOR PARAMETER V(REG) Regulator output voltage TEST CONDITIONS IO ≤ 25 mA, ∆V(REGTEMP) Regulator output change with temperature ∆V(REGLINE) ∆V(REGLOAD) Line regulation V(SD) = 6.5 V ≤ VCC ≤ 25 V, IO = 25 mA V(SD) =6.5 V ≤ VCC ≤ 25V, Load regulation 0.1 mA ≤ IO ≤ 25 mA, TA = − 25°C to 85°C TA = −25°C to 25°C MIN TYP MAX UNIT 3.135 3.3 3.465 V ± 0.2% ± 1.74% ± 0.2% ± 1.74% TA = 25°C to 85°C IO = 25 mA VCC = 14 V 6 20 mV 2 20 mV SHUTDOWN VI MONITOR PARAMETER TEST CONDITIONS V(SD) ∆V(SD) VREG shutdown threshold range(1) Measured at VBAT Shutdown threshold steps Set by SDV register b0 −b3 Vhys(SD) Hysteresis MIN TYP 6.475 MAX 10.975 300 35 50 UNIT V mV 65 mV ± 5% Accuracy of the shutdown threshold (1) V(SD) = V(REG) brownout threshold voltage as determined by b0 −b3 in the SDV register. BROWNOUT VIN MONITOR PARAMETER TEST CONDITIONS VBO ∆VBO Brownout threshold range(1) Measured at VBAT Brownout threshold steps Set by SDV register b4 − b7 Vhys(BO) Hysteresis MIN TYP 7.975 MAX 12.475 300 35 50 65 UNIT V mV ± 5% Brownout threshold accuracy (1) VBO = V(REG) brownout threshold voltage as determined by b4 −b7 in the SDV register. CELL VOLTAGE MONITOR PARAMETER TEST CONDITIONS V(CELL_OUT) VCELL output (see Note 4) V(CELL_IN) = 0 V V(CELL_IN) = 4.5 V V(CELL_IN) Differential Input voltage range VC1 to VC2, VC2 to VC3, VC3 to VC4, VC4 to VC5 K VCELL scale factor [0.975 −V(CELL_OUT) ]/V(CELL_IN) R(BAL) Cell balance internal resistance RDS(ON) for internal FET switch at V(DS) = 2 V MIN TYP MAX 0.975 V 0.3 0 0.144 4.5 0.150 500 UNIT V 0.156 Ω (1) The V(CELL) output is inversely proportional to the V(CELL_OUT) = −K × V(CELL_IN) + 0.975. 3 
 www.ti.com SLUS487D − DECEMBER 2001 − REVISED NOVEMBER 2003 ELECTRICAL CHARACTERISTICS CONTINUED TA = 25°C, CREG = 1 µF, VCC = 14 V (unless otherwise noted) OVERCURRENT (OC) AND SHORT CIRCUIT (SC) DETECTION PARAMETER TEST CONDITIONS MIN 205 Discharge (overload) −50 −205 ∆V(OCD) OC detection threshold program step Vhys(OCD) OC detection threshold hysteresis Charge and discharge (overcurrent and overload) V(SC) SC detection threshold range, typical(2) Charge ∆V(SC) SC detection threshold program step Vhys(SC) SC detection threshold hysteresis V(SC_acr) Charge (overcurrent) 5 Discharge (overload) −5 Discharge 7 mV 13 mV mV −100 −475 25 mV −25 Charge and discharge Charge and discharge Charge and discharge mV 475 Discharge SC detection threshold accuracy(2) 10 UNIT 100 Charge OC detection threshold accuracy(1) MAX 50 V(OCD) V(OCD_acr) TYP Charge (overcurrent) OC detection threshold range, typical(1) 40 50 60 V(OCD) = 50 mV (min) V(OCD) = 100 mV 37.5 50 62.5 85 100 115 V(OCD) = 205 mV (max) V(SC) = 100 mV (min) 174 205 236 75 100 125 V(SC) = 200 mV V(SC) = 475 mV (max) 170 200 230 403 475 547 MIN TYP MAX 1 5 7 mV mV mV (1) See OCVD and OCVC registers for setting detection threshold. (2) See SCV register for setting detection threshold. FET DRIVE CIRCUIT PARAMETER V(FETOL) V(FETCLAMP) TEST CONDITIONS Output voltage Output clamp voltage VBAT = 16 V DSG VPACK = 16 V CHG 1 5 7 VPACK = 16 V PCHG 8.5 10.5 11.5 VPACK = 4.5 V PCHG 3.3 3.5 3.7 10 100 DSG tr Rise time CL = 4700 pF, 10% to 90% CHG Fall time CL = 4700 pF, 90% to 10% V V µs 10 100 170 500 DSG 15 100 CHG 15 100 170 500 TYP MAX UNIT 50 100 Ω 2.9 3.15 3.46 V MIN TYP MAX UNIT 60 100 140 6 10 14 PCHG tf UNIT PCHG µs THERMISTOR DRIVE AND LED DRIVE PARAMETER TEST CONDITIONS R(t) TOUT pass-element series resistance IO = −1 mA at TOUT pin, R(t) = (VREG – VTOUT )/1 mA, TA = − 25°C to 85°C V(LEDOUT) LEDOUT output voltage IO = − 25 mA at LEDOUT pin, TA = − 25°C to 85°C MIN LOGIC PARAMETER R(PUP) VO(L) 4 Internal pullup resistance Logic low-level output voltage TEST CONDITIONS XALERT, CLKIN SDATA, SCLK XALERT, IOUT = 200 µA SDATA, IOUT = 50 µA TA = − 25°C to 85°C 0.2 0.4 kΩ V 
 www.ti.com SLUS487D − DECEMBER 2001 − REVISED NOVEMBER 2003 ELECTRICAL CHARACTERISTICS CONTINUED TA = 25°C, CREG = 1 µF, VCC = 14 V (unless otherwise noted) AC PARAMETER TEST CONDITIONS f(CLKIN) t(CLKIN_HI) CLKIN input frequency External clock CLKIN high time External clock f(INTERNAL) Internal clock frequency t(SCDDELAY) SC delay time TA = − 25°C to 85°C td(SC) = 0 ms for charge and discharge V(OCD) = 100 mV, SR(50%) to DSG/CHG(50%) delay. No load. MIN TYP MAX 32.100 32.768 33.420 2 28 26.2 32.768 39.4 1 10 UNIT kHz µs kHz µs Terminal Functions TERMINAL NAME DESCRIPTION NO. CHG 21 Push-pull output charge FET gate voltage supply CLKIN 16 Digital input that provides an alternate clock with internal 100-kΩ pullup to VREG CNTL 10 Active low input enables CHG, DSG and PCHG. Internal pullup DSG 23 Push-pull output discharge FET gate voltage supply GND 11, 13 Analog ground pin and negative pack terminal LEDOUT 20 Provides current to drive LED capacity display PCHG 22 Push-pull output precharge FET gate voltage supply SCLK 14 Open-drain bidirectional serial interface clock with internal 10-kΩ pullup to VREG SDATA 15 Open-drain bidirectional serial interface data with internal 10-kΩ pullup to VREG SR1 8 Current sense positive terminal when charging relative to SR2 SR2 9 Current sense positive terminal when discharging relative to SR1 TOUT 18 Provides thermistor bias current VBAT 2 Battery positive terminal sense input for regulator shutdown VC1 3 Sense voltage input terminal for most positive cell and balance current input for most positive cell. Connected to VC2 in 3-cell applications VC2 4 Sense voltage input terminal for second most positive cell, balance current input for second most positive cell, and return balance current for most positive cell VC3 5 Sense voltage input terminal for third most positive cell, balance current input for third most positive cell and return balance current for second most positive cell VC4 6 Sense voltage input terminal for least positive cell, balance current input for least positive cell, and return balance current for third most positive cell VC5 7 Sense voltage input terminal for most negative cell, return balance current for least positive cell VCC 1 Diode protected BAT+ terminal and primary power source VCELL 12 Output of scaled value of the measured cell voltage VPACK 24 Pack positive terminal and alternate power source VREG 19 Integrated 3.3-V regulator output XALERT 17 Open-drain output used to indicate status register changes. With internal 100 kΩ pullup to VREG 5 
 www.ti.com SLUS487D − DECEMBER 2001 − REVISED NOVEMBER 2003 FUNCTIONAL BLOCK DIAGRAM Pack+ VCC CNTL DSG 1 CNTL CHG VPACK PCHG 21 23 24 22 VREG 10 1uA CHG/DSG Output Control PCHG Output Control Thermistor Drive 18 TOUT VBAT 2 3.3V Regulator EN VC1 3 Cell Select VC2 VC3 5 VC4 Network Switch 4 Input Shutdown Monitor CLKGEN Delay Control 19 VREG To internal Circuitry 100k VREF Startup Balance Back-Up CLK Input Brownout Monitor 6 Cell Voltage Monitor VC5 20 LEDOUT LED Drive Status Logic 17 XALERT 16 CLKIN 100k 7 − OC for Discharge − OC for Charge − SC for Discharge SR1 8 Over-Current Short-Current Sensing SR2 9 − Brownout − SC for Charge VCELL 12 Pack− Cell Select GND OCVD/OCVC SCV OCD/SCD Control SDV 13 VREG VREG 11 Communication 10k 6 Status 10k 20 15 SCLK SDATA GND 
 www.ti.com SLUS487D − DECEMBER 2001 − REVISED NOVEMBER 2003 AC TIMING SPECIFICATIONS (I2C COMPATIBLE SERIAL INTERFACE) tsu(STA) tw(H) tf tw(L) tr SCLK tr SDATA Start Condition SDA Input 1 SCLK Stop Condition SDA Change th(DAT) th(STA) tf 2 th(ch) tsu(DAT) 3 7 8 9 MSB SDATA ACK Start Condition tv tsu(STOP) SCLK SDATA 1 2 3 MSB 7 8 9 tsu(BUF) ACK Stop Condition PARAMETER MIN MAX UNIT 300 ns 300 ns 300 ns 300 ns tr tf Clock rise time tr(SDA) tf(SDA) SDA rise time 20 SDA fall time 20 tsu(STA) tw(H) Clock high to input transition setup time 600 ns Clock pulse width high 600 ns th(STA) th(DAT) Input low to clock low hold time start condition 600 ns 0 µs tw(L) tsu(DAT) Clock pulse width low 1.3 µs Input transition to clock transition setup time 100 ns tsu(STOP) tsu(BUF) Clock high to input high (STOP) setup time stop condition 600 ns Input high to input low (bus free) 1.3 µs tv th(CH) Clock low to data out valid time 200 Data out hold time after clock low 200 f(CLK) Clock frequency Clock fall time Clock low to input transition hold time 900 ns ns 100 kHz 7 
 www.ti.com SLUS487D − DECEMBER 2001 − REVISED NOVEMBER 2003 APPLICATION INFORMATION PRECHARGE MODE CURRENT LIMITING RESISTOR SELECTION The selection of this resistor value should take into account the maximum potential charge voltage, which should include the voltage of a failed charger to ensure that 0-V and pre-charge mode current levels are within desirable limits under all conditions. I(PCHG) RDS(ON) BAT PACK+ R(PCHG) I (PCHG) + VPACK(max) * VBAT(min) RDS(ON) ) R(PCHG) 22 PCHG UDG−01148 Figure 1. Pre-Charge Mode Current Limiting Resistor Selection This method ensures that the resistor is sized correctly to provide safe zero voltage charging and the optimal performance during precharge. 8 7 6 5 4 3 10 2 1 23 SR1 8 VC5 VC4 VC3 VC2 VC1 CNTL VBAT DSG VCC CHG 21 19 24 CLKIN XALERT SDATA SCLK LEDOUT 12 16 17 15 14 20 VREG TOUT 18 VPACK VCELL SR2 GND GND 9 13 11 PCHG 22 LED1 24 NC 25 LED3 22 LED2 23 VSSD VSSD VSSD VSSA 19 11 38 30 29 VSSP 5 NC 37 NC 27 SR2 4 NC 13 NC NC 36 EVENT 18 LED5 20 LED4 21 17 DISP 35 CLKOUT 28 SR1 OC 3 TS 2 XCK2 33 XCK1 34 FILT 32 SMBC 15 SMBD 16 31 VCCA 10 SDATA 6 SCLK 7 NC 8 VCCD 1 VIN 14 NC 26 MRST 9 RBI 12 SAFE www.ti.com SLUS487D − DECEMBER 2001 − REVISED NOVEMBER 2003
 Figure 2. bq29311 Application Circuit Example Including Battery Management Host Controller 9 
 www.ti.com SLUS487D − DECEMBER 2001 − REVISED NOVEMBER 2003 FUNCTIONAL DESCRIPTION INTEGRATED REGULATOR The input for this regulator is derived from the battery cell stack or the pack positive terminal, with a valid range of VSD to 25 V. These two source inputs are ORed internally. An external diode is required to protect uncontrolled charging. The output is typically 3.3 V ±5% (TA = −25_C to 85_C) with a maximum output current of 25 mA. The output capacitance for stable operation is typically 1 µF. The output voltage line regulation is ±20 mV (max) between VSD and 25 V. The load regulation is ±20 mV (max) over the current range of 0. 1 mA to 25 mA. The regulator output starts up only when VPACK reaches the valid input voltage. After this voltage is reached, the bios of the regulator is supplied through VBAT from the battery, even if VPACK voltage is removed. SHUTDOWN AND BROWNOUT If the voltage at VBAT falls below 7.975 V± 5%(default), the bq29311 sets the BRWO bit to 1 in STATUS (b4) and triggers the XALERT output. The value in the SDV register (b4−b7) determines the threshold value and this can be programmed from 7.975 V to 12.475 V in 0.3-V steps (with an accuracy of ±5% at the falling edge) and has 50 mV ±30% of hysteresis. Reading the STATUS register clears XALERT in a brownout, but OCL (CONTROL, b0) must be taken from 0 to 1 to 0; then STATUS must be read, to clear the BRWO bit. If the voltage at VBAT is below 6.475V ±5% (default) the regulator can be shut down. The value in the SDV register (b0−3) determines the threshold value, which can be programmed from 6.475 V to 10.975 V in 0.3-V steps with an accuracy of ±5% at the falling edge and has 50 mV ±30% of hysteresis. When the input voltage is below the shutdown threshold and a higher voltage at VPACK is not present, then SHDN (STATUS, b5) is set and the bq29311 enters the sleep mode and turns off CHG, DSG, and PCHG. The current consumption in this mode is under 1 µA. SHDN is cleared when the input voltage rises above the shutdown threshold. XALERT does not respond to shutdown. OVERCURRENT, OVERLOAD,AND SHORT-CIRCUIT DETECTION The overcurrent, overload, and short-circuit detection is used to detect abnormal current in either the charge or discharge direction. This safety feature is used to protect the pass FETs, cells, and any other inline components from excessive current conditions. The detection circuit also incorporates a blanking delay before driving the control for the pass FETs to turn off. 10 The overcurrent, overload, and short-circuit thresholds are set in the OCVD/C and SCV registers with defaults of 50 mV and 100 mV respectively. The individual overcurrent (charge) , and overload (discharge) thresholds can be programmed from 50 mV to 205 mV in 5-mV steps with a hysteresis of 10 mV ±30%. The single short-circuit threshold can be programmed from 100 mV to 475 mV in 25-mV steps with a hysteresis of 50 mV ±20%. OVERCURRENT, OVERLOAD AND SHORT-CIRCUIT DELAY The overcurrent and overload delays allow the system to momentarily accept a high current condition. The default overcurrent delay is 1 ms. The delay time can be increased via the OCD register, where the overcurrent and overload delays can be independently defined. The OCD register can be programmed for a range of 1 ms to 31 ms with steps of 2 ms. The short-circuit delay has a default value of 0 ms and is also programmable in the SCD register. This register can be programmed from 0 to 915 µs with steps of 61 µs. OVERCURRENT, OVERLOAD AND SHORT-CIRCUIT RESPONSE When an overcurrent, overload, or short-circuit condition is detected, the CHG and DSG FETs are turned off and the PCHG FET turned on, limiting the charge current to the pre-charge rate. The STATUS (b0...b3) register reports the details of discharge short circuit, charge short circuit, overload (discharge overcurrent) and overcurrent. The respective STATUS (b0...b3) bits are set to 1 and the XALERT output changes state. This condition is latched until the CONTROL (b0) is set and then reset. If a FET is turned on by resetting CONTROL (b0) and the error condition is still on the system, then the device again enters the protection response state. CELL VOLTAGE The cell voltage is translated to allow a system host to measure individual series elements of the battery. The series element voltage is translated to a GND-based voltage equal to 0.15 of the series element voltage. This provides a range from 0 V to 4.5 V. The translation output is inversely proportional to the input. V(CELL_OUT) = −K × V(CELL_IN) + 0.975 (V) Programming CELL_SEL (b0...b1) selects the individual series element. The CELL_SEL (b2 . . . b3) selects the measurement mode for the series elements. This allows the offset to be determined for each element in the string. 
 www.ti.com SLUS487D − DECEMBER 2001 − REVISED NOVEMBER 2003 CALIBRATION OF CELL VOLTAGE MONITOR AMPLIFIER GAIN The cell voltage monitor amplifier has an offset, which can be calibrated to increase accuracy. The following procedure shows how to measure and calculate the offset: 1. Set CAL2=0, CAL1=1, VM1=0, VM0=0 The output voltage includes the offset and is represented by VOUT1 = 0.975 + (1 + K) × VOS (V) where K = VCELL scaling factor VOS = offset voltage at input of the internal op-amp 2. Set CAL2=1, CAL1=0, VM1=0, VM0=0 The output voltage includes the scale factor error and offset and is represented by VOUT2 = 0.975 + (1 + K) × VOS – K × 0.975 (V) 3. Calculate (VOUT1 – VOUT2)/0.975 The result is the actual scaling factor, KACT and is represented by KACT = (VOUT1–V OUT2)/0.975 = (0.975 + (1 + K) × VOS) − (0.975 + (1 + K) × VOS – K × 0.975)/0.975 = K × 0.975/0.975 = K 4. Calculate the actual offset value where VOS(ACT) = (VOUT1 – 0.975)/(1 + KACT) 5. Calibrated cell voltage is calculated by VCn − VC(n+1) = [0.975 + (1 + KACT ) × VOS(ACT) – VCELLOUT]/KACT The default-state of the FET drive is off. A host can control the FET drive by programming CONTROL (b1...b2) where b1 is used to control the external discharge FET and b2 is used to control the external charge FET. These controls are valid only when shutdown is not active. PCHG FET DRIVER CONTROL The PCHG FET is used when the battery is under voltage, allowing limited conditioning current modes such as pre-charge and 0 V charging. At startup of the bq29311 (charger connected to battery pack), PCHG is clamped to 3.5 V when VPACK is 3.8 V to 5.25 V. Thus the actual VPACK voltage is decided with this PCHG clamp voltage and the VGS(gate-source voltage) of external precharge FET. When VPACK is over 5.25 V, PCHG voltage would be controlled to two-thirds of VPACK. The default state of PCHG is on. There are two methods to pull up PCHG to turn off precharge FET. One is through the control register via serial communication. Setting b3 in the control register to 1 turns off the precharge FET. Another method is to use CNTL. Floating CNTL or pulling CNTL up to VREG turns off the precharge FET and also the CHG and DSG FETs. Overcurrent, overload, and short-circuit detection is not applied during precharge operations. An external resistor located in series with the external precharge FET limits the current flow for precharge operations. 20.0 The cell balance control allows a small discharge to be controlled for any one series element. The purpose of this discharge is to bring the series elements to the same voltage. Series resistors placed between the input pins and the positive series element nodes control the discharge current value. Individual series element selection is made using CELL_SEL (b4...b7). Cell balance discharge is also disabled if bits CELL_SEL (b4...b7) are zero. When all CELL_SEL (b4…b7) bits are set to 1, then all series elements are discharged. VPCHG − Push-Pull Output Voltage − V CELL BALANCE CONTROL 16.7 15.0 10.0 5.0 3.5 DSG AND CHG FET DRIVER CONTROL The bq29311 drives the FET off if an OC or SC safety threshold is breached. The host can force any FET on or off only if the bq29311 integrated protection control allows. The DSG and CHG FET drive gate-to-drain voltage is clamped to 15 V (max) and 11 V (typ). 0 3.8 5.25 10 15 20 25 VPACK − Pack Positive Voltage − V 30 Figure 3. PCHG Drive Output vs. Pack Voltage (Design Simulation) 11 
 www.ti.com SLUS487D − DECEMBER 2001 − REVISED NOVEMBER 2003 THERMISTOR DRIVE CIRCUIT The TOUT pin can be enabled to drive a thermistor from VREG. The typical thermistor resistance is 10 kΩ at 25°C. The default-state for this is OFF to conserve power. The maximum output impedance is 100 Ω. TOUT (b6 of the control register) enables or disables this function. TOUT (b6 of CONTROL register) enables or disables this feature. LED DRIVE CIRCUIT The LED drive provides a current source from VREG. LEDEN (b5 of the control register) enables or disables this function. Transitions of the CLKIN pin hold off the internal oscillator so if the external input stops oscillating, the internal oscillator starts and enables all the timing functions. COMMUNICATIONS The I2C compatible serial communications provides read and write access to the bq29311 data area. The data is clocked via separate data (SDATA) and clock (SCLK) pins. The bq29311 acts as a slave device and does not generate clock pulses. Communication to the bq29311 can be provided from GPIO pins or an I2C supporting port of a host system controller. The slave address for the bq29311 is 7 bits and the value is 0100 000 (0x20). ADDRESS (0X20) CONTROL INPUT (CNTL) The control input is pulled up internally to VREG, which disables all the FET outputs. When CNTL is pulled to GND, the bq29311 control outputs are then controlled by safety and register control logic. An external pullup can be added to enable a pullup to a higher voltage. This could cause up to an extra 100 µA leakage through the CNTL input to GND. 5 4 3 2 1 0 0 1 0 0 0 0 0 The bq29311 does not have the following functions compatible with the I2C specification. D D CLOCK INPUT (CLKIN) The clock input allows for an external time base to be used for increased accuracy in delay timing when determining overcurrent and short-circuit holdoff. The standard frequency is 32.768 kHz but must be above 30 kHz. This input is pulled up via an internal 100-kΩ resistor. 6 The bq29311 is always regarded as a slave. The bq29311 does not support the general code of the I2C specification and therefore does not return an ACK, but returns a NACK instead. D The bq29311 does not support the address auto increment, which allows continuous reading and writing. D The bq29311 allows data to be written or read from the same location without resending the location address. SCLK SDATA A6 A5 A4 A0 R/W ACK 0 Start R7 R6 R5 R0 ACK 0 D7 D6 D5 D0 0 Slave Address ACK 0 Register Address Data NOTE: Slave = bq29311 Figure 4. I2C-Bus Write to bq29311 SCLK SDATA Start A6 A5 A0 R/W ACK 0 Slave Address 0 R7 R6 R0 ACK Register Address A6 A0 R/W ACK 1 0 Slave Address NOTE: Slave = bq29311 Figure 5. I2C-Bus Read from bq29311: Protocol A 12 D7 D6 Slave Drives The Data D0 NACK Master Drives NACK and Stop Stop 
 www.ti.com SLUS487D − DECEMBER 2001 − REVISED NOVEMBER 2003 SCLK A6 SDATA Start A5 A0 R/W ACK 0 Slave Address R7 R6 0 R0 ACK Register Address A6 A5 Stop Start A0 R/W ACK D7 Slave Address D0 Slave Drives The Data NOTE: Slave = bq29311 NACK Master Stop Drives NACK and Stop Figure 6. I2C-Bus Read from bq29311: Protocol B REGISTER MAP The bq29311 has nine addressable registers. These registers provide status, control, and configuration information for the battery-protection system. All registers except for status are read/write. All registers are reset on power up of the bq29311. ADDRESS TYPE STATUS NAME 0x00 R DESCRIPTION CONTROL 0x01 R/W bq29311 control from system host SDV 0x02 R/W Brownout/shutdown threshold voltage OCVD 0x03 R/W Overcurrent threshold voltage for discharge (overload) OCVC 0x04 R/W Overcurrent threshold voltage for charge OCD 0x05 R/W Overcurrent and overload delay time CELL_SELECT 0x06 R/W Battery cell select for cell translation and balance discharge SCV 0x07 R/W Short-circuit threshold voltage for discharge and charge SCD 0x08 R/W Short-circuit delay time for discharge and charge bq29311 status STATUS register STATUS REGISTER (0X00) 7 6 5 4 3 2 1 0 − − SHDN BRWO OCCHG OCDSG SCCHG SCDSG The status register provides information about the current state of the bq29311. Reading the status register clears the XALERT pin after OCL (CONTROL, b0) has been cleared unless otherwise stated. STATUS b0 (SCDSG): This bit indicates a short circuit in the discharge direction. 0 = below the short-circuit threshold in the discharge direction (default) 1 = greater than or equal to the short-circuit threshold in the discharge direction STATUS b1 (SCCHG): This bit indicates a short-circuit in the charge direction. 0 = below the short-circuit threshold in the charge direction (default) 1 = greater than or equal to the short-circuit threshold in the charge direction STATUS b2 (OCDSG): This bit indicates an overload condition. 0 = less than or equal to the overcurrent threshold in the discharge direction (default) 1 = greater than overcurrent threshold in the discharge direction STATUS b3 (OCCHG): This bit indicates an overcurrent condition. 0 = less than or equal to the overcurrent threshold in the charge direction (default) 1 = greater than overcurrent threshold in the charge direction STATUS b4 (BRWO): This bit indicates that the brownout voltage threshold has been reached. 0 = greater than the brownout threshold (default) 1 = less than or equal to the brownout threshold voltage STATUS b5 (SHDN): This bit shows that the battery voltage has fallen below the shutdown threshold limit, indicating a shutdown condition. 0 = greater than the shutdown threshold voltage (default) 1 = less than or equal to the shutdown threshold voltage 13 
 www.ti.com SLUS487D − DECEMBER 2001 − REVISED NOVEMBER 2003 CONTROL REGISTER CONTROL REGISTER (0X01) 7 6 5 4 3 2 1 0 SVDOFF TOUT LEDEN VMOFF PCHG CHG DSG OCL The CONTROL register controls the outputs of the bq29311 and can be used to clear certain states set by any OC, SC or brownout condition. The OCL latch must be cleared before the STATUS register is read to clear the register. CONTROL b0 (OCL): This bit releases the overcurrent latch when toggled from 0 to 1 back to 0 (default = 0) after the latch has been set by any OC or SC condition. CONTROL b1 (DSG): This bit controls the external discharge FET. 0 = discharge FET is off and is controlled by the system host (default) 1 = discharge FET is on and the bq29311 is in normal operating mode CONTROL b2 (CHG): This bit controls the external charge FET. 0 = charge FET is off and is controlled by the system host (default) 1 = charge FET is on and the bq29311 is in normal operating mode. CONTROL b3 (PCHG): This bit controls the external precharge FET. 0 = precharge FET is on and controlled by the system host for enabling a charge path prior to turning on the charge FET (default) 1 = precharge FET is off. CONTROL b4 (VMOFF): This bit enables or disables the voltage monitoring translation function and cell balance discharge. 0 = enables voltage monitoring (default) 1 = disables voltage monitoring CONTROL b5 (LEDEN): This bit enables or disables the LED driver function 0 = disables LED drive function (default) 1 = enables LED drive function CONTROL b6 (TOUT): This bit controls the VCC power to the thermistor. 0 = thermistor power is off (default) 1 = thermistor power is on CONTROL b7 (SDVOFF): This bit enables or disables the shutdown monitor function. 0 = shutdown monitor enabled (default) 1 = shutdown monitor disabled 14 
 www.ti.com SLUS487D − DECEMBER 2001 − REVISED NOVEMBER 2003 SDV: SHUTDOWN VOLTAGE SDV REGISTER (0X02) 7 6 5 4 3 2 1 0 BOV3 BOV2 BOV1 BOV0 SDV3 SDV2 SVD1 SDV0 The SDV register is used to configure the regulator shutdown and brownout thresholds. 00000000 is the default. SDV b3...b0 With Corresponding Threshold 0000 6.475 V 0100 7.675 V 1000 8.875 V 1100 10.075 V 0001 6.775 V 0101 7.975 V 1001 9.175 V 1101 10.375 V 0010 7.075 V 0110 8.275 V 1010 9.475 V 1110 10.675 V 0011 7.375 V 0111 8.575 V 1011 9.775 V 1111 10.975 V SDV b7...b4 With Corresponding Threshold 0000 7.975 V 0100 9.175 V 1000 10.375 V 1100 11.575 V 0001 8.275 V 0101 9.475 V 1001 10.675 V 1101 11.875 V 0010 8.575 V 0110 9.775 V 1010 10.975 V 1110 12.175 V 0011 8.875 V 0111 10.075 V 1011 11.275 V 1111 12.475 V OCVD: OVERCURRENT (OVERLOAD) VOLTAGE THRESHOLD IN DISCHARGE OCVD REGISTER (0X03) 7 6 5 4 3 2 1 0 − − − OCVD4 OCVD3 OCVD2 OCVD1 OCVD0 OCVD b0−b4 (OCVD0−OCVD4): These five bits select the value of the overcurrent threshold in the discharge direction. 00000 is the default. OCVD b4...b0 With Corresponding Threshold 00000 0.050 V 01000 0.090 V 10000 0.130 V 11000 0.170 V 00001 0.055 V 01001 0.095 V 10001 0.135 V 11001 0.175 V 00010 0.060 V 01010 0.100 V 10010 0.140 V 11010 0.180 V 00011 0.065 V 01011 0.105 V 10011 0.145 V 11011 0.185 V 00100 0.070 V 01100 0.110 V 10100 0.150 V 11100 0.190 V 00101 0.075 V 01101 0.115 V 10101 0.155 V 11101 0.195 V 00110 0.080 V 01110 0.120 V 10110 0.160 V 11110 0.200 V 00111 0.085 V 01111 0.125 V 10111 0.165 V 11111 0.205 V OCVC: OVERCURRENT VOLTAGE THRESHOLD REGISTER OCVC REGISTER (0X04) 7 6 5 4 3 2 1 0 − − − OCVC4 OCVC3 OCVC2 OCVC1 OCVC0 OCVC b0−b4 (OCVC0 −OCVC4): These five bits select the value of the overcurrent threshold in the charge direction. 00000 is the default. OCVC b4...b0 With Corresponding Threshold 00000 0.050 V 01000 0.090 V 10000 0.130 V 11000 0.170 V 00001 0.055 V 01001 0.095 V 10001 0.135 V 11001 0.175 V 00010 0.060 V 01010 0.100 V 10010 0.140 V 11010 0.180 V 00011 0.065 V 01011 0.105 V 10011 0.145 V 11011 0.185 V 00100 0.070 V 01100 0.110 V 10100 0.150 V 11100 0.190 V 00101 0.075 V 01101 0.115 V 10101 0.155 V 11101 0.195 V 00110 0.080 V 01110 0.120 V 10110 0.160 V 11110 0.200 V 00111 0.085 V 01111 0.125 V 10111 0.165 V 11111 0.205 V 15 
 www.ti.com SLUS487D − DECEMBER 2001 − REVISED NOVEMBER 2003 OCD: OVERCURRENT/OVERLOAD BLANKING DELAY OCD REGISTER (0X05) 7 6 5 4 3 2 1 0 OCDC3 OCDC2 OCDC1 OCDC0 OCDD3 OCDD2 OCDD1 OCDD0 This register is used to set the overcurrent and overload delay times. OCD b0−b3 (OCDD0−OCDD3): These four bits select the value of the delay time for overcurrent triggering in the discharge direction. 0000 is the default. OCD b3...b0 With Corresponding Delay Time 0000 1 ms 0100 9 ms 1000 17 ms 1100 25 ms 0001 3 ms 0010 5 ms 0101 11 ms 1001 19 ms 1101 27 ms 0110 13 ms 1010 21 ms 1110 29 ms 0011 7 ms 0111 15 ms 1011 23 ms 1111 31 ms OCD b4−b7 (OCDC0−OCDC3): These four bits select the value of the delay time for overcurrent triggering in the charge direction. 0000 is the default. OCD b7...b4 With Corresponding Delay Time 0000 1 ms 0100 9 ms 1000 17 ms 1100 25 ms 0001 3 ms 0010 5 ms 0101 11 ms 1001 19 ms 1101 27 ms 0110 13 ms 1010 21 ms 1110 0011 7 ms 29 ms 0111 15 ms 1011 23 ms 1111 31 ms SCV: SHORT-CIRCUIT THRESHOLD VOLTAGE SCV REGISTER (0X07) 7 6 5 4 3 2 1 0 − − − − SCV3 SCV2 SCV1 SCV0 This register selects the common short-circuit threshold voltage for both charge and discharge. SCV b0−b3 (SCV0−SCV3): These four bits select the value of the short-circuit voltage threshold for both charge and discharge. 0000 is the default. SCV b0...b3 With Corresponding Threshold Voltage 0000 0.10V 0100 0.20V 1000 0.30V 1100 0.40V 0001 0.125V 0101 0.225V 1001 0.325V 1101 0.425V 0010 0.150V 0110 0.250V 1010 0.350V 1110 0.450V 0011 0.175V 0111 0.275V 1011 0.375V 1111 0.475V SCD: SHORT-CIRCUIT BLANKING DELAY SCD REGISTER (0X08) 7 6 5 4 3 2 1 0 SCDC3 SCDC2 SCDC1 SCDC0 SCDD3 SCDD2 SCDD1 SCDD0 This register selects the short-circuit blanking delay time for charge and discharge. SCD b0−b3 (SCDD0−SCDD3): These four bits select the value of the short-circuit delay time for discharge. Exceeding the short-circuit voltage threshold for longer than this period turns off the DSG output. 0000 is the default. SCD b3...b0 With Corresponding Delay Time 0 µs 0100 244 µs 1000 488 µs 1100 732 µs 0001 61 µs 0101 305 µs 1001 549 µs 1101 793 µs 0010 122 µs 0110 366 µs 1010 610 µs 1110 854 µs 0011 183 µs 0111 427 µs 1011 671 µs 1111 915 µs 0000 SCD b4−b7 (SCDC0−SCDC3): These four bits select the value of the short-circuit delay time for charge. Exceeding the short-circuit voltage threshold for longer than this period turns off the CHG output. 16 
 www.ti.com SLUS487D − DECEMBER 2001 − REVISED NOVEMBER 2003 SCD b7...b4 With Corresponding Delay Time 0 µs 0100 244 µs 1000 488 µs 1100 732 µs 0001 61 µs 0101 305 µs 1001 549 µs 1101 793 µs 0010 122 µs 0110 366 µs 1010 610 µs 1110 854 µs 0011 183 µs 0111 427 µs 1011 671 µs 1111 915 µs 0000 CELL_SELECT: CELL SELECTION CELL_SELECT REGISTER (0X06) 7 6 5 4 3 2 1 0 CELL4 CELL3 CELL2 CELL1 CAL1 CAL0 VM1 VM0 This register determines cell selection for voltage measurement and translation, cell balancing and the operational mode of the cell voltage monitoring. CELL_SELECT b0−b1 (VM0−VM1) These two bits select the series cell for voltage measurement translation. VM1 VM0 0 0 Bottom series element (default) SELECTED CELL 0 1 Second lowest series element 1 0 Second highest series element 1 1 Top series element CELL_SELECT b2−b3 (CAL0, CAL1): These bits determine the mode of the voltage monitor block. CAL1 CAL0 MEASUREMENT MODE 0 0 Cell translation for selected cell (default) 0 1 Offset measurement for selected cell 1 x Monitor the VREF value for gain calibration CELL_SELECT b3 −b6 (CELL1 −CELL4): These four bits select the series cell for cell balance discharge. Cell balance discharge is disabled if bits b4...b7 are set to zero (default), and all cells are discharged if bits b4...b7 are set to 1. CELL1 =1 = bottom series element CELL2 =1 = second lowest series element CELL3 =1 = second highest series element CELL4 =1 = top series element Figure 2 shows a typical application for the bq29311 smart lithium-ion battery protector. All functions required to protect three- or four-series lithium-ion cells from overcharge and over-discharge, as well as provide short-circuit protection, are included in a single chip. An R-C filter is recommended at the VCELL pin where R(VCELL) = 100 Ω (typ) and C(VCELL) = 100 nF (typ) CELL CONNECTION ORDER The cells should be connected in the following order: Bat− to VC5, Bat+ to VC1, top of bottom cell to VC4, top of second cell to VC3 and top of third cell to VC2. 3 OR 4 CELL CONFIGURATION The 4-series cell configuration is shown in Figure 1. In a 3-cell configuration, VC1 is shorted to VC2, and R3 and C13 are removed. VC2, VC3, VC4, and VC5 pins are used for three cells. 17 PACKAGE OPTION ADDENDUM www.ti.com 13-Jul-2022 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) Device Marking (3) Samples (4/5) (6) BQ29311PW ACTIVE TSSOP PW 24 60 RoHS & Green NIPDAU Level-1-260C-UNLIM -25 to 85 29311PW Samples BQ29311PWR ACTIVE TSSOP PW 24 2000 RoHS & Green NIPDAU Level-1-260C-UNLIM -25 to 85 29311PW Samples (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of