Product Folder Order Now Support & Community Tools & Software Technical Documents bq77904, bq77905 SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 bq77905, bq77904 3-5S Ultra Low-Power Voltage, Current, Temperature, and Open Wire Stackable Lithium-ion Battery Protector 1 Features 3 Description • • The bq77904 and bq77905 devices are low-power battery pack protectors that implement a suite of voltage, current, and temperature protections without microcontroller (MCU) control. The device's stackable interface provides simple scaling to support battery cell applications from 3 S to 20 S or more. Protection thresholds and delays are factory-programmed and available in a variety of configurations. Separate overtemperature and undertemperature thresholds for discharge (OTD and UTD) and charge (OTC and UTC) are provided for added flexibility. 1 • • • • • • • Normal Mode: 6 µA (bq77904/bq77905) Full suite of voltage, current and temperature protections Scalable cell count from 3 S to 20 S or more Voltage Protection (Accuracy ±10 mV) – Overvoltage: 3 V to 4.575 V – Undervoltage: 1.2 V to 3 V Open Cell and Open Wire Detection (OW) Current Protection – Overcurrent Discharge 1: –10 mV to –85 mV – Overcurrent Discharge 2: –20 mV to 170 mV – Short Circuit Discharge: –40 mV to 340 mV – Accuracy ±20% for ≤ 20 mV, ±30% for > 20 mV across full temperature Temperature Protection – Overtemperature Charge: 45°C or 50°C – Overtemperature Discharge: 65°C or 70°C – Undertemperature Charge: –5°C or 0°C – Undertemperature Discharge: –20°C or –10°C Additional Features – Independent Charge (CHG) and Discharge (DSG) FET Drivers – 36-V Absolute Maximum Rating Per Cell Input – Built-In-Self-Test Functions For High Reliability Shutdown Mode: 0.5 µA Maximum 2 Applications • • • • • • Power Tools, Garden Tools Start-Stop Battery Packs Lead-Acid (PbA) Replacement Batteries Light Electric Vehicles Energy Storage Systems, Uninterruptible Power Supplies (UPS) 10.8 V to 72 V Packs The device achieves pack protection through the integrated independent CHG and DSG low-side NMOS FET drivers, which may be disabled through two control pins. These control pins may also be used to achieve cell protection solutions for higher series (6 S and beyond) in a simple and economical manner. To do this, simply cascade a higher device CHG and DSG outputs to the immediate lower device control pins. For reduced component count, all protection faults use internal delay timers. Device Information(1) PART NUMBER PACKAGE bq77904 BODY SIZE (NOM) TSSOP (20) bq77905 6.50 mm × 4.40 mm (1) For all available packages, see the orderable addendum at the end of the data sheet. Simplified Schematic PACK+ VDD VTB VC5 TS bq77094/5 LD Vss SRP SRN DSG CHGU CTRD CTRC VDD VTB VC5 TS bq77094/5 LD Vss SRP SRN DSG CHG PACK- Copyright © 2016, Texas Instruments Incorporated 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. bq77904, bq77905 SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 www.ti.com Table of Contents 1 2 3 4 5 6 7 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Device Comparison ............................................... Pin Configuration and Functions ......................... Specifications......................................................... 7.1 7.2 7.3 7.4 7.5 7.6 7.7 8 1 1 1 2 3 4 5 Absolute Maximum Ratings ...................................... 5 ESD Ratings.............................................................. 5 Recommended Operating Conditions....................... 5 Thermal Information .................................................. 6 Electrical Characteristics........................................... 6 Timing Requirements ................................................ 9 Typical Characteristics ............................................ 10 Detailed Description ............................................ 12 8.1 Overview ................................................................. 12 8.2 Functional Block Diagram ....................................... 13 8.3 Feature Description................................................. 14 8.4 Device Functional Modes........................................ 25 9 Application and Implementation ........................ 26 9.1 Application Information............................................ 26 9.2 Typical Application .................................................. 32 9.3 System Examples ................................................... 36 10 Power Supply Recommendations ..................... 36 11 Layout................................................................... 37 11.1 Layout Guidelines ................................................. 37 11.2 Layout Example .................................................... 37 12 Device and Documentation Support ................. 38 12.1 12.2 12.3 12.4 12.5 12.6 Documentation Support ....................................... Receiving Notification of Documentation Updates Community Resources.......................................... Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 38 38 38 38 38 38 13 Mechanical, Packaging, and Orderable Information ........................................................... 38 4 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision D (March 2017) to Revision E Page • Added bq7790505 to Device Comparison table..................................................................................................................... 3 • Changed UTC(REC) at 5°C typ from 68.8 to 69.73 %VTB. Changed UTC(REC) at 10°C typ from 64.23 to 65.52 %VTB .. 7 Changes from Revision C (February 2017) to Revision D • Changed VOTD, VOTD(REC), VOTC, VOTC(REC), VUTD, VUTD(REC), VUTC, VUTC(REC) MIN and MAX specification values................................................................................................................................................................. 6 Changes from Revision B (November 2016) to Revision C • Page Page Added values in the Thermal Information table to align with JEDEC standards.................................................................... 6 Changes from Revision A (June 2016) to Revision B Page • Changed order of listed items in Features ............................................................................................................................. 1 • Table 1 and Table 2, Changed OTC To: UTC in last column under Temperature. Changed bq7790400 and bq7790503 to production status. Updated bq7790503 configuration .................................................................................... 3 • Changed pin number from 16-pin to 20-pin .......................................................................................................................... 4 • Corrected max value on the UTD at –20°C spec ................................................................................................................... 7 • Changed comparator flow charts with new flow charts ........................................................................................................ 14 • Corrected CTRC and CTRD delay time entries ................................................................................................................... 18 Changes from Original (June 2016) to Revision A • 2 Page Changed the device From: Product Preview To: Production ................................................................................................. 1 Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 bq77904, bq77905 www.ti.com SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 5 Device Comparison DEVICE NUMBER OF CELLS bq77904 3, 4 bq77905 3, 4, 5 PROTECTIONS TYPICAL NORMAL MODE CURRENT (µA) PACKAGE 6 20-TSSOP OV, UV, OW, OTD, OTC, UTD, UTC, OCD1, OCD2, SCD, CTRC, CTRD Unless specified, the devices in Table 1 and Table 2 are default with state comparator enabled with 2 mV threshold. Filtered fault detection is used by default. Contact Texas Instruments for new configuration option or device in preview. Table 1. bq77904 Device Configuration (1) N 0 (disable) Delay (s) 200 Threshold (mV) 1 Delay (ms) Load Removal Recovery(Y/N) 2800 Current Fault Recovery SCD Threshold (mV) Hyst(mV) 100 OCD2 Delay (ms) Delay(s) 1 OCD1 Threshold (mV) Thresh (mV) 4225 Current(nA) Hyst(mV) OW Delay(s) Part Number bq7790400 UV Threshold(mV) OV Method 40 1420 80 700 160 0 Load Removal Temperature (°C) (1) OTD OTC UTD UTC 70 50 -20 -5 These thresholds are target based on temperature, but they are dependent on external components that could vary based on customer selection. Circuit is based on 103AT NTC thermistor connected to TS and VSS, and a 10kΩ resistor connected to VTB and TS. Actual thresholds must be determined in mV. Refers to the over- and under-temperature mV threshold in the Electrical Characteristics table. Table 2. bq77905 Device Configuration Current Fault Recovery Delay (s) Threshold (mV) SCD Delay (ms) OCD2 Threshold (mV) Delay (ms) OCD1 Threshold (mV) Current(nA) Load Removal Recovery(Y/N) OW Hyst(mV) Delay(s) Thresh (mV) UV Hyst(mV) Delay(s) Part Number Threshold(mV) OV Temperature (°C) (1) Method OTD OTC UTD UTC 70 50 -20 0 bq7790500 4200 0.5 100 2600 1 400 Y 100 30 1420 50 700 120 1 Load Removal + Delay bq7790501 (2) 4200 0.5 100 2600 1 400 N 100 30 1420 50 700 120 1 Load Removal + Delay 70 50 -20 0 bq7790502 4250 1 200 2700 1 200 Y 100 85 700 120 350 240 — Load Removal 70 50 -20 -5 4200 1 100 2700 2 400 Y 100 80 1420 160 350 320 1 Load Removal 70 50 -20 -5 1 Load Removal + Delay 70 50 -10 -5 9 Load Removal + Delay 65 45 -20 0 bq7790503 bq7790504 bq7790505 (1) (2) (2) 4250 4250 0.5 1 200 200 2700 2700 1 1 200 200 Y N 100 0 80 60 350 10 160 80 5 5 200 100 These thresholds are target based on temperature, but they are dependent on external components that could vary based on customer selection. Circuit is based on 103AT NTC thermistor connected to TS and VSS, and a 10kΩ resistor connected to VTB and TS. Actual thresholds must be determined in mV. Refers to the over- and under-temperature mV threshold in the Electrical Characteristics table. Product Preview Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 3 bq77904, bq77905 SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 www.ti.com 6 Pin Configuration and Functions PW Package 20-Pin TSSOP Top View VDD 1 20 DVSS AVDD 2 19 CTRD VC5 3 18 CTRC VC4 4 17 CCFG VC3 5 16 VTB VC2 6 15 TS VC1 7 14 LD AVSS 8 13 CHG SRP 9 12 CHGU SRN 10 11 DSG Not to scale Pin Functions PIN I/O (1) DESCRIPTION NAME NO. AVDD 2 O Analog supply (only connect to a capacitor) AVSS 8 P Analog ground CCFG 17 I Cell in series-configuration input CHG 13 O CHG FET driver, use on a single device or on the bottom device of a stack configuration CHGU 12 O CHG FET signal, use for upper device of a stack configuration to feed the CHG signal to the CTRC pin of the lower device CTRC 18 I CTRD 19 I DSG 11 O DSG FET driver DVSS 20 P Digital ground LD 14 I PACK– load removal detection SRN 10 I Current sense input connecting to the pack– side of sense resistor SRP 9 I Current sense input connecting to the battery side of sense resistor TS 15 I Thermistor measurement input. Connect a 10kΩ resistor to AVSS pin if the function is not used VC1 7 I VC2 6 I VC3 5 I VC4 4 I VC5 3 I Cell voltage sense inputs (pin 3 must be connected to pin 4 on bq77904) VDD 1 P Supply voltage VTB 16 O Thermistor bias output (1) 4 CHG and DSG override inputs Cell voltage sense inputs I = Input, O = Output, P = Power Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 bq77904, bq77905 www.ti.com SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 7 Specifications 7.1 Absolute Maximum Ratings Over operating free-air temperature range (unless otherwise noted). All values are referenced to VSS unless otherwise noted. (1) VDD, VC5, VC4, VC3, VC2, VC1, CCFG, CTRD, CTRC VI Input voltage MAX UNIT 36 V LD –30 20 V SRN, SRP, TS, AVDD, CCFG –0.3 3.6 V DSG, CHGU –0.3 20 V CHG –30 20 V VTB –0.3 VO Output voltage range II Input current LD, CHG II Input current IO IO 3.6 V 500 µA CHGU, DSG 1 mA Output current CHG 1 mA Output current CHGU, DSG 1 mA 150 °C Storage temperature, Tstg (1) MIN –0.3 –65 Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. 7.2 ESD Ratings VALUE V(ESD) (1) (2) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) ±1000 Charged-device model (CDM), per JEDEC specification JESD22-C101 (2) ±250 UNIT V JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. 7.3 Recommended Operating Conditions Over operating free-air temperature range (unless otherwise noted). VBAT VI Supply voltage Input voltage MIN MAX UNIT VDD 3 25 V VC5-VC4, VC4-VC3, VC3-VC2, VC2-VC1, VC1-VSS 0 5 CTRD, CTRC 0 (VDD + 5) CCFG 0 AVDD –0.2 0.8 SRN, SRP VO Output voltage TA Operating free-range temperature LD 0 16 TS 0 VTB CHG, CHGU, DSG 0 16 VTB, AVDD 0 3 –40 85 Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 V V °C 5 bq77904, bq77905 SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 www.ti.com 7.4 Thermal Information THERMAL METRIC bq77904 bq77905 (1) UNITS PW (TSSOP) 20 PINS RθJA Junction-to-ambient thermal resistance RθJC(top) Junction-to-case (top) thermal resistance RθJB Junction-to-board thermal resistance ψJT ψJB (1) 98.4 °C/W 37 °C/W 49.3 °C/W Junction-to-top characterization parameter 2.9 °C/W Junction-to-board characterization parameter 48.7 °C/W For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report. 7.5 Electrical Characteristics Typical values stated at TA = 25ºC and VDD = 16 V (bq77904) or 20 V (bq77905). MIN and MAX values stated with TA = –40ºC to +85ºC and VDD = 3 to 20 V (bq77904) or VDD = 3 to 25 V (bq77905) unless otherwise noted. PARAMETER TEST CONDITIONS MIN TYP MAX UNIT SUPPLY VOLTAGE V(POR) POR threshold VDD rising, 0 to 6 V V(SHUT) Shutdown threshold VDD falling, 6 to 0 V V(AVDD) AVDD voltage C(VDD) = 1 µF 2 2.1 4 V 3.25 V 2.5 3.25 V 9 µA SUPPLY AND LEAKAGE CURRENT ICC Normal mode current (bq77904/bq77905) Cell1 through Cell5 = 4 V, VDD = 20 V (bq77905) 6 I(CFAULT) Fault condition current State comparator on 8 IOFF Shutdown mode current VDD < VSHUT ILKG(OW_DIS) Input leakage current at VCx pins All cell voltages = 4 V, Open Wire disable configuration ILKG(100nA) Open-wire sink current at VCx pins ILKG(200nA) ILKG(400nA) 12 µA 0.5 µA –100 0 100 nA All cell voltages = 4 V, 100 nA configuration 30 110 175 nA Open-wire sink current at VCx pins All cell voltages = 4 V, 200 nA configuration 95 210 315 nA Open-wire sink current at VCx pins All cell voltages = 4 V, 400 nA configuration 220 425 640 nA PROTECTION ACCURACIES VOV Overvoltage programmable threshold range 3000 4575 mV VUV Undervoltage programmable threshold range 1200 3000 mV TA = 25ºC, OV detection accuracy –10 10 mV TA = 25ºC, UV detection accuracy –18 18 mV TA = 0 to 60ºC –28 26 mV TA = –40 to 85ºC –40 40 mV VHYS(OV) OV hysteresis programmable threshold range 0 400 mV VHYS(UV) UV hysteresis programmable threshold range 200 800 mV VOTD Overtemperature in discharge programmable threshold V(VA) OV, UV, detection accuracy VOTD(REC) (1) 6 Threshold for 65°C (1) 19.71 20.56 21.86 %VTB 17.36 18.22 19.51 %VTB Recovery threshold at 55°C for when VOTD is at 65°C (1) 25.24 26.12 27.44 %VTB Recovery threshold at 60°C for when VOTD is at 70°C (1) 22.12 23.2 24.24 %VTB Threshold for 70°C Overtemperature in discharge recovery (1) Based on a 10 KΩ pull-up and 103AT thermistor. Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 bq77904, bq77905 www.ti.com SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 Electrical Characteristics (continued) Typical values stated at TA = 25ºC and VDD = 16 V (bq77904) or 20 V (bq77905). MIN and MAX values stated with TA = –40ºC to +85ºC and VDD = 3 to 20 V (bq77904) or VDD = 3 to 25 V (bq77905) unless otherwise noted. PARAMETER VOTC VOTC(REC) Overtemperature in charge recovery VUTD Undertemperature in discharge programmable threshold VUTD(REC) Undertemperature in discharge recovery VUTC VUTC(REC) TEST CONDITIONS Overtemperature in charge programmable threshold MIN TYP MAX UNIT Threshold for 45°C (1) 32.14 32.94 34.54 %VTB Threshold for 50°C (1) 29.15 29.38 31.45 %VTB Recovery threshold at 35°C when VOTD is at 45°C (1) 38.63 40.97 40.99 %VTB Recovery threshold at 40°C when VOTD is at 50°C (1) 36.18 36.82 38.47 %VTB (1) 86.41 87.14 89.72 %VTB Threshold for –10°C (1) 80.04 80.94 83.10 %VTB Recovery threshold at –10°C when VUTD is at –20°C (1) 80.04 80.94 83.10 %VTB Recovery threshold at 0°C when VUTD is at –10°C (1) 71.70 73.18 74.86 %VTB Threshold for –5°C (1) 75.06 77.22 78.32 %VTB Threshold for 0°C (1) 71.70 73.18 74.86 %VTB Recovery threshold at 5°C when VUTC is at –5°C (1) 68.80 69.73 71.71 %VTB Recovery threshold at 10°C when VUTC is at 0°C (1) 64.67 65.52 67.46 %VTB Threshold for –20°C Undertemperature in charge programmable threshold Undertemperature in Charge Recovery VOCD1 Overcurrent discharge 1 programmable threshold range, (VSRP – VSRN) –85 –10 mV VOCD2 Overcurrent discharge 2 programmable threshold range, (VSRP – VSRN) –20 –170 mV VSCD Short circuit discharge programmable threshold range, (VSRP – VSRN) –40 –340 mV VCCAL OCD1 detection accuracy at lower VOCD1 > –20 mV thresholds –30% 30% VCCAH OCD1, OCD2, SCD detection accuracy VOCD1 ≤ –20 mV; all OCD2 and SCD threshold ranges –20% 20% VOW Open-wire fault voltage threshold at VCx per cell with respect to VCx-1 Voltage falling on VCx, 3.6 V to 0V 450 VOW(HYS) Hysteresis for open wire fault Voltage rising on VCx, 0 V to 3.6 V 500 550 100 mV mV CHARGE AND DISCHARGE FET DRIVERS VDD ≥ 12 V, CL = 10 nF 11 VDD < 12 V, CL = 10 nF VDD - 1 12 V(FETON) CHG/CHGU/DSG on V(FETOFF) CHG/CHGU/DSG off R(CHGOFF) CHG off resistance CHG off for > tCHGPDN and pin held at 2V 0.5 R(DSGOFF) CHGU/DSG off resistance CHGU/DSG off and pin held at 2V 10 ICHG(CLAMP) CHG clamp current CHG off and pin held at 18 V VCHG(CLAMP) CHG clamp voltage ICHG(CLAMP) = 300 µA tCHGON CHG on rise time tDSGON CHGU/DSG on rise time tCHGOFF tDSGOFF No load when CHG/CHGU/DSG is off 14 V VDD V 0.5 V kΩ 16 Ω 450 µA 18 20.5 V CL = 10 nF, 10% to 90% 50 150 µs CL = 10 nF, 10% to 90% 2 75 µs CHG off fall time CL = 10 nF, 90% to 10% 15 30 µs CHGU/DSG off fall time CL = 10 nF, 90% to 10% 5 15 µs 0.6 V 16 CTRC AND CTRD CONTROL VCTR1 Enable FET driver (VSS) With respect to VSS. Enabled < MAX Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 7 bq77904, bq77905 SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 www.ti.com Electrical Characteristics (continued) Typical values stated at TA = 25ºC and VDD = 16 V (bq77904) or 20 V (bq77905). MIN and MAX values stated with TA = –40ºC to +85ºC and VDD = 3 to 20 V (bq77904) or VDD = 3 to 25 V (bq77905) unless otherwise noted. PARAMETER TEST CONDITIONS MIN TYP MAX VDD + 2.2 UNIT VCTR2 Enable FET driver (Stacked) Enabled > MIN V VCTR(DIS) Disable FET driver Disabled between MIN and MAX VCTR(MAXV) CTRC and CTRD clamp voltage ICTR = 600nA tCTRDEG_ON) (2) CTRC and CTRD de-glitch for ON signal 7 ms tCTRDEG_OFF (2) CTRC and CTRD de-glitch for OFF signal 7 ms 2.04 VDD + 2.8 VDD + 4 VDD + 0.7 V VDD + 5 V CURRENT STATE COMPARATOR V(STATE_D1) Discharge qualification threshold1 Measured at SRP-SRN -3 –2 -1 mV V(STATE_C1) Charge qualification threshold1 Measured at SRP-SRN 1 2 3 mV 1.2 ms tSTATE (2) State detection qualification time LOAD REMOVAL DETECTION VLD(CLAMP) LD clamp voltage I(LDCLAMP) = 300 µA ILD(CLAMP) LD clamp current V(LDCLAMP) = 18 V 16 VLDT LD threshold Load removed < when VLDT 1.25 RLD(INT) LD input resistance when enabled Measured to VSS tLD_DEG LD detection de-glitch 18 20.5 V 450 µA 1.3 1.35 V 160 250 375 kΩ 1 1.5 2.3 ms 10 %AVDD 100 %AVDD 45 %AVDD CCFG PIN V(CCFGL) CCFG threshold low (ratio of VAVDD) 3 cell configuration V(CCFGH) CCFG threshold high (ratio of VAVDD) 4 cell configuration 65 V(CCFGHZ) CFG threshold high-Z (ratio of VAVDD) 5 cell configuration, CCFG floating, internally biased 25 tCCFG_DEG (2) CCFG de-glitch 33 6 ms CUSTOMER TEST MODE V(CTM) Customer test mode entry voltage at VDD VDD > VC5 + V(CTM), TA = 25°C 8.5 50 10 V tCTM_ENTRY (3) Delay time to enter and exit customer test mode VDD > VC5 + V(CTM), TA = 25°C tCTM_DELAY (3) Delay time of faults while in customer test mode TA = 25°C 200 ms Fault recovery time of OCD1, OCD2, and SCD faults while in customer test mode 1 s and 8 s options, TA = 25°C 100 ms tCTM_OC_REC (2) (3) 8 (3) ms Not production tested parameters. Specified by design Device is in no fault state prior to entering Customer Test Mode. Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 bq77904, bq77905 www.ti.com SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 7.6 Timing Requirements MIN TYP MAX 0.5 s Delay Option 0.4 0.5 0.8 1 s Delay Option 0.8 1 1.4 2 s Delay Option 1.8 2 2.7 UNIT PROTECTION DELAYS (1) tOVn_DELAY Overvoltage detection delay time 4.5 s Delay Option tUVn_DELAY Undervoltage detection delay time 4 4.5 5.2 1 s Delay Option 0.8 1 1.5 2 s Delay Option 1.8 2 2.7 4.5 s Delay Option 4 4.5 5.5 9 s Delay Option 8 9 10.2 s s tOWn_DELAY Open-wire detection delay time 3.6 4.5 5.3 s tOTC_DELAY Overtemperature charge detection delay time 3.6 4.5 5.3 s tUTC_DELAY Undertemperature charge detection delay time 3.6 4.5 5.3 s tOTD_DELAY Overtemperature discharge detection delay time 3.6 4.5 5.3 s tUTD_DELAY Undertemperature discharge detection delay time 3.6 4.5 5.3 s 10 ms delay option 8 10 15 20 ms delay option 17 20 26 45 ms delay option 36 45 52 90 ms delay option 78 90 105 180 ms delay option 155 180 205 350 ms delay option 320 350 405 700 ms delay option 640 700 825 1420 ms delay option 1290 1420 1620 4 5 8 10 ms delay option 8 10 15 20 ms delay option 17 20 26 45 ms delay option 36 45 52 90 ms delay option 78 90 105 180 ms delay option 155 180 205 350 ms delay option 320 350 405 tOCD1_DELAY Overcurrent 1 detection delay time 5 ms delay option tOCD2_DELAY tSCD_RELAY tCD_REC (1) Overcurrent 2 detection delay time 700 ms delay option 640 700 825 Short-circuit detection delay time 360 µs delay option 220 400 610 Overcurrent 1, Overcurrent 2, and Short-circuit recovery delay time 1 s option 0.8 1 1.4 9 s option 8 9 10.2 ms ms µs s Not production tested parameters. Specified by design Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 9 bq77904, bq77905 SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 www.ti.com 7.7 Typical Characteristics 7.5 0.25 0.2 Shutdown Current (PA) Normal Mode Current (PA) 7 6.5 6 5.5 5 0.15 0.1 0.05 4.5 -15 10 35 Temperature (qC) 60 0 -40 85 -15 Figure 1. Normal Mode Current 10 10 5 UV Error (mV) 5 OV Error (mV) 60 85 D002 Figure 2. Shutdown Current 15 0 -5 -10 0 -5 -10 -15 -15 -20 -40 10 35 Temperature (qC) D001 -15 10 35 Temperature (qC) 60 -20 -40 85 -15 10 35 Temperature (qC) D003 Figure 3. OV Error at 4.25 V Threshold 85 D004 Figure 4. UV Error at 2.8 V Threshold 0.2 0.1 60 4.0 2.5 0.05 3.5 0.0 2 ±0.2 -0.1 ±0.4 -0.15 -0.2 ±0.6 -0.25 Error (in mV) Error (in %) -0.3 -0.35 ±40 ±20 0 20 40 60 2.5 1.5 2.0 1 1.5 1.0 Error (in mV) Error (in %) 0 ±1.0 ±40 ±20 0 20 40 60 0.5 0.0 80 Temperature (ºC) C001 Figure 5. OCD1 Error at 40 mV Threshold 10 3.0 0.5 ±0.8 80 Temperature (ºC) OCD2 Error (mV) -0.05 OCD1 Error (%) OCD1 Error (mV) 0 OCD2 Error (%) 4 -40 C002 Figure 6. OCD2 Error at 60 mV Threshold Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 bq77904, bq77905 www.ti.com SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 Typical Characteristics (continued) 1.6 2.5 1.4 1.2 1.0 1.5 0.8 1 0.6 SCD Error(%) SCD Error (mV) 2 0.4 0.5 Error (in mV) Error (in %) 0 ±40 ±20 0 20 40 60 0.2 0.0 80 Temperature (ºC) C003 Figure 7. SCD Error at 160 mV Threshold Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 11 bq77904, bq77905 SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 www.ti.com 8 Detailed Description 8.1 Overview The bq77904 and bq77905 families are full-feature stackable primary protectors for Li-ion/Li-polymer batteries. The devices implement a suite of protections including: • Cell voltage: overvoltage, undervoltage • Current: Overcurrent discharge 1 and 2, short circuit discharge • Temperature: overtemperature and undertemperature in charge and discharge • PCB: cell open wire connection • FET body diode protection Protection thresholds and delays are factory-programmed and available in a variety of configurations. The bq77904 supports 3S-to-4S cell configuration and bq77905 supports 3S-to-5S cell configuration. Up to 4 devices can be stacked to support ≥6S cell configuration, providing protections up to 20S cell configuration. The device has built-in CHG and DSG drivers for low-side N-channel FET protection, which automatically opens up the CHG and/or DSG FETs after protection delay time when a fault is detected. A set of CHG/DSG override is provided to allow disabling of CHG and/or DSG driver externally. Although host system can use this function to disable the FETs control, the main usage of these pins is to channel down the FET control signal from the upper device to the lower device in a cascading configuration in ≥6S battery pack. 8.1.1 Device Functionality Summary For brevity, in this and subsequent sections, a number of abbreviations will be used to identify specific fault conditions. The fault descriptor abbreviations and their meanings are defined in Table 3. Table 3. Device Functionality Summary FAULT DESCRIPTOR OV FAULT DETECTION THRESHOLD and DELAY OPTIONS FAULT RECOVERY METHOD and SETTING OPTIONS Overvoltage 3 V to 4.575 V (25 mV step) 0.5, 1, 2, 4.5 s Hysteresis 0, 100, 200, 400 mV UV Undervoltage 1.2 V to 3 V (100 mV step for < 2.5 V, 50 mV step for ≥ 2.5 V) 1, 2, 4.5, 9 s Hysteresis, OR Hysteresis + Load Removal 200, 400 mV OW Open Wire (cell to pcb disconnection) 0 (disabled), 100, 200, or 400 nA 4.5 s Restore bad VCx to pcb connection VCx > VOW OTD (1) Overtemperature during Discharge 65°C or 70°C 4.5 s Hysteresis 10°C OTC (1) Overtemperature during Charge 45°C or 50°C 4.5 s Hysteresis 10°C UTD (1) Undertemperature during Discharge -20°C or -10°C 4.5 s Hysteresis 10°C Undertemperature during Charge -5°C or 0°C 4.5s Hysteresis 10°C Delay, OR Delay + Load Removal , OR Load Removal 1 s or 9 s UTC (1) OCD1 Overcurrent1 during Discharge 10 mV to 85 mV (5 mV step) 10, 20, 45, 90, 180, 350, 700, 1420 ms OCD2 Overcurrent1 during Discharge 20 mV to 170 mV (10 mV step) 5, 10, 20, 45, 90, 180, 350, 700 ms SCD Short Circuit Discharge 40 mV to 340 mV (20 mV step) 360 µs tCTRDEG_ON Enable via external control or via CHGU signal from the upper device in stack configuration tCTRDEG_OFF tCTRDEG_ON Enable via external control or via DSG signal from the upper device in stack configuration tCTRDEG_OFF CTRC CHG signal override control Disable via external control or via CHGU signal from the upper device in stack configuration CTRD DSG signal override control Disable via external control or via DSG signal from the upper device in stack configuration (1) 12 These thresholds are target based on temperature, but they are dependent on external components that could vary based on customer selection. Circuit is based on 103AT NTC thermistor connected to TS and VSS, and a 10-kΩ resistor connected to VTB and TS. Actual thresholds must be determined in mV. Refers to the over- and under-temperature mV threshold in the Electrical Characteristics table. Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 bq77904, bq77905 www.ti.com SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 8.2 Functional Block Diagram VDD CCFG CONFIG LOGIC BG REFERENCE BIAS AVDD VDIG REGULATOR AND SHUTDOWN VTB POR TS VC5 VC4 EEPROM MUX VC3 COMPARE 1 CTRC VC2 STACK INTERFACE CTRD VC1 EQUINOX CONTROL LOGIC (ECL) OPEN WIRE CHG CHG DRIVER CHGU MUX COMPARE 2 DSG DRIVER DSG LOAD DETECTION LD SRP STATE COMPARE SRN CLOCK and WDT AVSS DVSS Copyright © 2016, Texas Instruments Incorporated Figure 8. bq77904 and bq77905 Block Diagram Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 13 bq77904, bq77905 SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 www.ti.com 8.3 Feature Description 8.3.1 Protection Summary The bq77904 and bq77905 have two comparators. Both are time multiplexed to detect all protection fault conditions. Each of the comparators runs on a time-multiplexed schedule and cycles through the assigned protection-fault checks. Comparator 1 checks for OV, UV, and OW protection faults. Comparator 2 checks for OCD1, OCD2, SCD, OTC, OTD, UTC, and UTD protection faults. For OV, UV, and OW protection faults, every cell is checked individually in round-robin fashion starting with cell 1 and ending with the highest-selected cell. The number of the highest cell is configured using the CCFG pin. Devices can be ordered with various timing and hysteresis settings. See the Device Comparison section for a summary of options available per device type. Check OV VCELL1 Check OV VCELL2 n = the highest call configured by CCFG pin Check OV VCELLn NO Time to check UV? Time to check OW? YES NO YES Check OW VCELLx, x = x +1 Check UV VCELL1 Check UV VCELL2 x starts from 1 at POR Reset x = 1, if x > the highest cell configured via CCFG pin Check UV VCELLn Turn off Comp1 until next cycle start Figure 9. Comparator 1 Flow Chart Check SCD Time to check OCD1? YES Check OCD1 NO Time to check OCD2? YES Check OCD2 NO Time to check OT? YES Check OT NO Time to check UT? NO YES Check UT Figure 10. Comparator 2 Flow Chart 14 Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 bq77904, bq77905 www.ti.com SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 Feature Description (continued) 8.3.2 Fault Operation 8.3.2.1 Operation in OV An OV fault detection is when at least one of the cell voltages is measured above the OV threshold, VOV. The CHG pin is turned off if the fault condition lasts for a duration of OV Delay, tOVn_DELAY. The OV fault recovers when the voltage of the cell in fault is below the (OV threshold - OV hysteresis, VHYS_OV) for a time of OV Delay. The bq77904, ba779055 assumes OV fault after device reset. 8.3.2.2 Operation in UV An UV fault detection is when at least one of the cell voltages is measured below the UV threshold, VUV. The DSG is turned off if the fault condition lasts for a duration of UV Delay, tUVn_DELAY. The UV fault recovers when: • the cell voltage in fault is above the (UV threshold + UV hysteresis, VHYS_UV) for a time of UV Delay only, OR • the cell voltage in fault is above the (UV threshold + UV hysteresis) for a time of UV Delay AND Load removal is detected If load removal is enabled as part of UV recovery requirement, The CHG FET RGS value should change to around 3 MΩ. Refer to the Using Load Detect For UV Fault Recovery section of this document for more detail. This requirement applies to load removal enabled for UV recovery only. Hence, if load removal is selected for current fault recovery but not for the UV recovery, a lower CHG FET RGS value (typical of 1MΩ) can be used to reduce the CHG FET turn off time. To minimize supply current, the device disables all overcurrent detection blocks anytime the DSG FET has been turned off (due to a fault or CTRD being driven to the DISABLED state). Upon recovery from fault or when CTRD is no longer externally driven, all overcurrent detection blocks reactivate before the DSG FET turns back on. 8.3.2.3 Operation in OW An OW fault detection is when at least one of the cell voltages is measured below the OW threshold, VOW. Both CHG and DSG are turned off if the fault condition lasts for a duration of OW Delay, tOWn_DELAY. The OW Fault recovers when the cell voltage in fault is above the OW threshold + OW hysteresis, VOW_HYS for a time of OW Delay. The tOWn_DELAY time starts when voltage at a given cell is detected below VOW threshold and is not from the time that the actual event of open wire occurs. During an open wire event, it is common that the device detects an undervoltage and/or overvoltage fault before detecting an open wire fault. This may happen due to the differences in fault thresholds, fault delays, and the VCx pin filter capacitor values. To ensure both CHG and DSG return to normal operation mode, the OW, OV and UV faults recovery conditions must be met. 8.3.2.4 Operation in OCD1 An OCD1 fault is when the discharge load is high enough that the voltage across the RSNS resistor, (VSRP-VSRN), is measured below the OCD1 voltage threshold, VOCD1. Both CHG and DSG are turned off if the fault condition lasts for a duration of OCD1 Delay, tOCD1_DELAY. The OCD1 Fault recovers when: • Load removal detected only, VLD < VLDT, OR • Overcurrent Recovery Timer, tCD_REC, expiration only , OR • Overcurrent Recovery Timer expiration and load removal detected 8.3.2.5 Operation in OCD2 An OCD2 fault is when the discharge load is high enough that the voltage across the RSNS resistor, (VSRP-VSRN), is measured below the OCD2 voltage threshold, VOCD2. Both CHG and DSG are turned off if the fault condition lasts for a duration of OCD2 Delay, tOCD2_DELAY. The OCD2 Fault recovers when: • Load removal detected only, VLD < VLDT, OR • Overcurrent Recovery Timer, tCD_REC, expiration only , OR Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 15 bq77904, bq77905 SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 www.ti.com Feature Description (continued) • Overcurrent Recovery Timer expiration and load removal detected 8.3.2.6 Operation in SCD An SCD fault is when the discharge load is high enough that the voltage across the RSNS resistor, (VSRP-VSRN), is measured below the SCD voltage threshold, VSCD. Both CHG and DSG are turned off if the fault condition lasts for a duraiton of SCD Delay, tSCD_DELAY. The SCD Fault recovers when: • Load removal detected only, VLD < VLDT, OR • Overcurrent Recovery Timer, tCD_REC, expiration only , OR • Overcurrent Recovery Timer expiration and load removal detected 8.3.2.7 Overcurrent Recovery Timer The timer expiration method simply activates an internal recovery timer as soon as the initial fault condition exceeds the OCD1/OCD2/SCD time. When the recovery timer reaches its limit, both CHG and DSG drivers are turned back on. If the combination option of timer expiration AND load removal is used, then the load removal condition is only evaluated upon expiration of the recovery timer, which can have an expiration period of tCD_REC. 8.3.2.8 Load Removal Detection The load removal detection feature is implemented with the LD pin (see Table 4). When no undervoltage fault and current fault conditions are present, the LD pin is held in an open drain state. Once any UV, OCD1, OCD2, or SCD fault occurs and load removal is selected as part of the recovery conitions, a high impedance pull-down path to VSS is enabled on the LD pin. With an external load still present, the LD pin will be externally pulled high – it is internally clamped to VLDCLAMP and should also be resistor-limited through RLD externally to avoid conducting excessive current. If the LD pin exceeds VLDT, this is interpreted as a load present condition. When the load is eventually removed, the internal high-impedance path to VSS should be sufficient to pull the LD pin below VLDT for tLD_DEG – this is interpreted as a load removed condition and is one of the recovery mechanisms selectable for undervoltage and overcurrent faults. PACK+ bq77094/5 Load Detect block When load detect is enabled, the LD pin is connected to Vss via the RLD_INT. VLDT LD pin RLD_INT RLD LOAD The load, RLD and RLD_INT create a resister divider, which the load detect circuit is used to detect when the load is removed. PACKFigure 11. Load Detection Circuit For Current Faults Recovery 16 Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 bq77904, bq77905 www.ti.com SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 Table 4. Load State LD PIN LOAD STATE ≥ VLDT Load present < VLOT for tLD_DEG Load removed 8.3.2.9 Load Removal Detection in UV During UV fault, only the DSG FET driver is turned off while the CHG FET driver remains on. When load removal is selected as part of the UV recovery condition, the active CHG FET driver would alter the resistor divider ratio of the load detection circuit. To ensure the load status can still be detected properly, it is required to increase the CHG FET external RGS value to about 3 MΩ. Refer to the Using Load Detect For UV Fault Recovery section of this document for more detail. Note that if load removal is only selected for the current fault recovery (and is not used for UV recovery), it is not required to use a larger CHG FET RGS value. 8.3.2.10 Operation in OTC An OTC Fault occurs when the temperature increases such that the voltage across an NTC thermistor goes below the OTC voltage threshold, VOTC. CHG is turned off if the fault condition lasts for an OTC Delay time, tOTC_DELAY. The state comparator is turned on when CHG is turned off. If a discharge current is detected, the device immediately switchs the CHG back on. The response time of the state comparator is typically in 700 µs and should not pose any disturbance in the discharge event. The OTC fault recovers when the voltage across thermistor gets above OTC recovery threshold, VOTC_REC for OTC delay time. 8.3.2.11 Operation in OTD An OTD fault is when the temperature increases such that the voltage across an NTC thermistor goes below the OTD voltage threshold, VOTD. Both CHG and DSG are turned off if the fault condition lasts for an OTD Delay time, tOTD_DELAY. The OTD fault recovers when the voltage across thermistor gets above OTD recovery threshold, VOTD_REC, a time of OTD Delay. 8.3.2.12 Operation in UTC A UTC fault occurs when the temperature decreases such that the voltage across an NTC thermistor gets above the UTC voltage threshold, VUTC. CHG is turned off if the fault condition lasts for a time of UTC Delay, tUTC_DELAY. The state comparator is turned on when CHG is turned off. If a discharge current is detected, the device will immediately switch the CHG back on. The response time of the state comparator is typically in 700 µs and should not pose any disturbance in the discharge event. The UTC fault recovers when the voltage across thermistor gets below UTC recovery threshold, VUTC_REC, a time of UTC Delay. 8.3.2.13 Operation in UTD A UTD fault occurs when the temperature decreases such that the voltage across an NTC thermistor goes above the UTD voltage threshold, VUTD. Both CHG and DSG are turned off if the fault condition lasts for a UTD Delay time. The UTD Fault recovers when the voltage across thermistor gets below UTD recovery threshold, VUTD_REC, a time of UTD Delay. 8.3.3 Protection Response and Recovery Summary Table 5 summarize how each fault condition affects the state of the DSG and CHG output signals, as well as the recovery conditions required to resume charging and/or discharging. As a rule, the CHG and DSG output drivers are enabled only when no respective fault conditions are present. When multiple simultaneous faults (such as an OV and OTD) are present, all faults must be cleared before the FET can resume operation. Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 17 bq77904, bq77905 SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 www.ti.com Table 5. Fault Condition, State, and Recovery Methods FAULT FAULT TRIGGER CONDITION CHG DSG RECOVERY METHOD TRIGGER DELAY RECOVERY DELAY tCTRDEG_ON tCTRDEG_OFF CTRC disabled CTRC disabled for delgitch delay time OFF — CTRC must be enabled for delgitch delay time CTRD disabled CTRD disabled for delgitch delay time — OFF CTRD must be enabled for delgitch delay time OV V(Cell) rises above VOV for delay time OFF — V(Cell) drops below VOV – VHYS_OV for delay tOVn_DELAY UV V(Cell) drops below VUV for delay time — OFF V(Cell) rises above VUV + VHYS_UV for delay tUVn_DELAY OW VCX – VCX-1 < VOW for delay time OFF OFF Bad VCX recovers such that VCX – VCX-1 > VOW + VOW_HYS for delay tOWn_DELAY OCD1, OCD2, SCD (VSRP - VSRN) < VOCD1, VOCD2, or VSCD for delay time OFF OFF Recovery delay expires, OR LD detects < VLDT, OR Recovery delay expires + LD detects < VLDT OTC (1) Temperature rises above TOTC for delay time OFF — Temp drops below TOTC – TOTC_REC for delay tOTC_DELAY OTD (1) Temperature rises above TOTD for delay time OFF OFF Temp drops below TOTD – TOTD_REC for delay tOTD_DELAY UTC (1) Temperature drops below TUTC for delay time OFF — Temperature rises above TUTC + TUTC_REC for delay tUTC_DELAY UTD (1) Temp drops below TUTD for delay time OFF OFF Temp rises above TUTD + TUTD_REC for delay tUTD_DELAY (1) tOCD1_DELAY, tOCD2_DELAY, tSCD_DELAY, tCD_REC TUTC, TUTD, TUTC_REC, and TUTD_REC correspond to the temperature produced by VUTC, VUTD, VUTC_REC, and VUTD_REC of the selected thermistor resistance. For bq77904 and bq77905 devices to prevent CHG FET damage, there are times when the CHG FET may be enabled even though an OV, UTC, OTC or CTRC low event has occurred. See the State Comparator section for details. 8.3.4 Configuration CRC Check And Comparator Built-In-Self-Test To improve reliability, the device has built in CRC check for all the factory-programmable configuration, such as the thresholds and delay time setting. When the device is set up in the factory, a corresponding CRC value is also programmed to the memory. During normal operation, the device compares the configuration setting against the programmed CRC periodically. A CRC error will reset the digital circuitry and increment the CRC fault counter. The digital reset forces the device to reload the configuration as an attempt to correct the configurations. A correct CRC check reduces the CRC fault counter. Three CRC faults counts will turn off both the CHG and DSG drivers. If FETs are opened due to CRC error, only a POR can recover the FET state and reset the CRC fault. In addition to the CRC check, the device also has built-in-self-test (BIST) on the comparators. The BIST runs in a scheduler, each comparator is checked for a period of time. If a fault is detected for the entire check period, the particular comparator is considered at fault, and both the CHG and DSG FETs is turned off. The BIST continuous to run by the scheduler even if a BIST fault is detected. If the next BIST result is good, the FET driver resumes normal operation. The CRC check and BIST check do not affect the normal operation of the device. However, there is not specific indication when a CRC or BIST error is detected besides turning off both CHG and DSG drivers. If there is no voltage, current or temperature fault condition present, but CHG and DSG drivers remain off, it is possible either CRC or BIST error is detected. User can POR the device to reset the device. 18 Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 bq77904, bq77905 www.ti.com SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 8.3.5 Fault Detection Method 8.3.5.1 Filtered Fault Detection The device detects a fault once the applicable fault is triggered after accumulating sufficient trigger sample counts. The filtering scheme is based on a simple add/subtract. Starting with the Triggered Sample Count cleared, the counts go up for a sample that is taken across the tested condition (for example, above the fault threshold when looking for a fault) and the counts go down for a sample that is taken before the tested condition (that is, below the fault threshold). Figure 12 shows an example of a signal that triggers a fault when accumulating 5 counts above the Fault Threshold. Once a fault has been triggered, the trigger sample counts reset and counts are incremented for every sample that is found to be below the Recovery Threshold. Note that with filtered detection, when the input signal falls below the fault threshold, the sample count does not reset but only counts down as shown in Figure 12. Therefore, it is normal to observe a longer delay time if a signal is right at the detection threshold. The noise can push the delay count to be counting up and down, resulting a longer time for the delay counter to reach its final accumulated trigger target. Based on Fault Trigger After 5 Counts Fault Threshold Recovery Threshold FAULT FAULT Sample Triggered Sample Count 0 1 2 3 4 3 2 1 2 3 4 5 0 0 0 0 0 0 0 0 0 0 0 0 1 2 1 2 3 4 5 0 0 0 Looking for a Fault Looking for a Recovery Looking for a Fault Figure 12. Fault Trigger Filtering 8.3.6 State Comparator A small, low-offset analog State comparator monitors the sense-resistor voltage (SRP-SRN) to determine when the pack is in a discharge state less than a minimum threshold, VSTATE_D or charge state greater than a maximum threshold, VSTATE_C. The State comparator is used to turn the CHG FET on to prevent damage or overheating during discharge in fault states that call for having only the CHG FET off, and vice versa for the DSG FET during charging in fault that call for having only the DSG FET off. Table 6 summarizes when the State comparator is operational. The State comparator is only on during faults detected that call for only one FET driver to be turned off. Table 6. State Comparator Operation Summary STATE COMP CHG DSG OFF ON ON Normal MODE VSTATE_C Detection ON OFF UV, CTRD VSTATE_D Detection OFF ON OV, UTC, OTC, CTRC OFF OFF OFF OCD1, OCD2, SCD, UTD, OTD, OW Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 19 bq77904, bq77905 SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 www.ti.com PACK IS CHARGING PACK IS DISCHARGING SRP - SRN VSTATE_D 0V VSTATE_C Figure 13. State Comparator Thresholds 8.3.7 DSG FET Driver Operation The DSG pin is driven high only when no related faults (UV, OW, OTD, UTD, OCD1, OCD2, SCD, and CTRD disabled) are present. It is a fast switching driver with a target on resistance of about 15-20 Ω and an off resistance of RDSGOFF. It is designed to allow customer to select the optimized RGS value to archive the desirable FET rise and fall time per the application requirement and the choice of FET characteristics. When the DSG FET is turned off, the DSG pin drives low, all overcurrent protection (OCD1, OCD2, SCD) is disabled to better conserve power. These resume operation when the DSF FET is turned on. The device provides FET body diode protection through the state comparator if one FET driver is on and the other FET driver is off. The DSG driver may be turned on to prevent FET damage if the battery pack is charging while a discharge inhibit fault condition is present. This is done the state comparator. The state comparator (with VSTATE_C threshold) remains on for the entire duration of a DSG fault with no CHG fault event. • If (SRP - SRN) ≤ VSTATE_C, no charge event is detected, the DSG FET output will remain OFF due to the present of a DSG fault • If (SRP - SRN) > VSTATE_C, a charge event is detected, the DSG FET output will turn ON for body diode protection See the State Comparator section for detail. The presence of any related faults as shown in Figure 14 results in the DSGFET_OFF signal. DSGFET_OFF_UVn DSGFET_OFF_OCD1 DSGFET_OFF_OCD2 DSGFET_OFF_SCD DSGFET_OFF DSGFET_OFF_UTD DSGFET_OFF_OTD OWn CTRD Figure 14. Faults That Can Qualify DSGFET_OFF 8.3.8 CHG FET Driver Operation The CHG and CHGU pin are driven high only when no related faults (OV, OW, OTC, UTC, OTD, UTD, OCD1, OCD2, SCD, and CTRC are disabled) are present or the pack has a discharge current where (SRP-SRN) < VSTATE_D1 . The CHG pin drives the CHG FET, which is for use on the single device configuration or by the bottom device in a stack configuration. The CHGU pin has the same logic state as the CHG pin and is for use in the upper device (in a multi-stack configuration) to provide the drive signal to the CTRC pin of the lower device and should never connect to the CHG FET directly. 20 Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 bq77904, bq77905 www.ti.com SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 Turning off the CHG pin has no influence on the overcurrent protection circuitry. The CHG pin is designed to switch on quickly and the target on resistance is about 2 kΩ. When the pin is turned off, the CHG driver pin is actively driven low and will together with PACK- voltage below ground. The CHG FET may be turned on to protect the FET's body diode if the pack is discharging, even if a charging inhibit fault condition is present. This is done through the state comparator. The State comparator (with VSTATE_D threshold) remains on for the entire duration of a DSG fault with no CHG fault event. • If (SRP - SRN) > VSTATE_D, no discharge event is detected, the CHG FET output will remain OFF due to the present of a CHG fault • If (SRP - SRN) ≤ VSTATE_D, a charge event is detected, the CHG FET output will turn ON for body diode protection The CHGFET_OFF signal is a result of the presence of any related faults as shown in Figure 15. CHGFET_OFF_OVn CHGFET_OFF_UTC CHGFET_OFF_OTC CHGFET_OFF_OCD1 CHGFET_OFF_OCD2 CHGFET_OFF CHGFET_OFF_SCD CHGFET_OFF_UTD CHGFET_OFF_OTD OWn CTRC Figure 15. Faults That Can Qualify CHGFET OFF 8.3.9 External Override of CHG and DSG Drivers The device allows direct disabling of the CHG and DSG drivers through the CTRC and CTRD pins respectively. The operation of CTRC and CTRD pins is shown in Figure 16. To support the SimpleStack solution for highercell count packs, these pins are designed to operate above the device’s VDD level. Simply connect a 10 MΩ resistor between a lower device CTRC and CTRD input pins to an upper device CHGU and DSG output pins (see schematics in Stacking Implementations. CTRC only enables or disables the CHG pin, while CTRD only enables or disables the DSG pin. When the CTRx pin is in the DISABLED region, the respective FET pin will be off, regardless of the state of the protection circuitry. When the CTRx pin is in either ENABLED region, the protection circuitry determines the state of the FET driver. Both CTRx pins apply the fault-detection filtered method to improve the robustness of the signal detection; a counter counts up if an ENABLED signal is sampled; the counter counts down if a DISABLED signal is sampled. When the counter counts up from 0% to > 70% of its full range, which take about 7 ms typical of a solid signal, the CTRx pins take the signal as ENABLED. If the counter counts down from 100% to < 30%, of its full range, which take about 7 ms typical of a solid signal, the CTRx pins take the signal as DISABLED. From a 0 count counter (solid DISABLE), a solid ENABLE signal takes about tCTRDEG_ON time to deglitch. From a 100% count (solid ENABLE), a solid DISABLE signal takes about tCTRDEG_OFF time to deglitch. Although such a filter scheme provides a certain level of noise tolerance, it is highly recommended to shield the CTRx traces and keep the traces as short as possible in the PCB layout design. The CTRx deglitch time will add onto the FET response timing on OV, UV, and OW faults in a stack configuration. The tCTRDEG_OFF time adds an additional delay to the fault detection timing and the tCTRDEG_ON time adds an additional delay to the fault recovery timing. Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 21 bq77904, bq77905 SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 www.ti.com ENABLED VCTR2 VCTRDIS (max) VDD DISABLED (FET OFF) VCTRDIS (min) VCTR1 ENABLED VSS CHG driver set by CTRC DSG driver set by CTRD Figure 16. External Override of CHG and DSG Drivers 8.3.10 Configuring 3S, 4S, or 5S Mode The bq77904 supports 3S and 4S packs, while the bq77905 supports 3S, 4S, and 5S packs. In order to avoid accidentally detecting a UV fault on unused (shorted) cell inputs, the device must be configured for the specific cell count of the pack. This is set with the configuration pin, CCFG, which is mapped as in Table 7. The device periodically checks the CCFG status and takes tCCFG_DEG time to detect the pin status. Table 7. CCFG Configurations CCFG CONFIGURATION CONNECT TO < VCCFGL for tCCFG_DEG 3 cells AVSS Within VCCFGM for tCCFG_DEG 4 cells AVDD > VCCFGH for tCCFG_DEG 5 cells Floating The CCFG pin should be tied to the recommended net from Table 7. The device compares the CCFG input voltage to the AVDD voltage and should never be set above the AVDD voltage. When the device configuration is for 5S, leave the CCFG pin floating. The internal pin bias is approximately 30% of the AVDD voltage for 5S configuration. Note that the bq77904 should be configured in 5S mode as this results in a permanent UV fault. 8.3.11 Stacking Implementations Higher than 5S cell packs may be supported by daisy-chaining multiple devices. Each device will ensure OV, UV, OTC OTD, UTC, and UTD protections, of its directly monitored cells, while any fault conditions automatically disable the global CHG and/or DSG FET driver. Note that upper devices do not provide OCD1, OCD2, or SCD protections, as these are based on pack current. For bq77904 and bq77905 used on the upper stack, the SRP and SRN pins should be shorted to prevent false detection. Table 8. Stacking Implementation Configurations CONFIGURATION CHG PIN CHGU PIN Bottom or single device Connect to CHG FET Leave unconnected Upper stack Leave unconnected Connect to CTRC of the lower device To configure higher-cell packs, follow this procedure: • Each device must have a connection on at least three lowest-cell input pins. • TI recommends to connect higher-cell count to the upper devices (for example, for a 7S configuration, connect 4 cells on the upper device and 3 cells on the bottom device). This is to provide stronger CRTx signal to the bottom device. • Ensure that each device’s CCFG pin is configured appropriately for its specific number of cells (three, four, or five cells). 22 Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 bq77904, bq77905 www.ti.com • • • • SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 For the bottom device, the CHG pin should be used to drive the CHG FET and leave the CHGU pin unconnected. For the upper device, the CHGU pin should be used to connect to lower device’s CTRC pin with a RCTRx and leave the CHG pin unconnected. Connect the upper DSG pins with a RCTRx to the immediate lower device CTRD pin All upper devices should have the SRP and SRN to its AVSS pin. If load removal is not used for UV recovery, connect the upper device LD pin to its AVSS pin shown in Figure 17 and Figure 18. Otherwise, refer to Figure 25 for proper LD connection. PACK+ RVDD CVDD CVDD RIN CIN RIN DVSS CTRD VC5 CTRC VC4 CCFG VC3 CIN RIN VDD AVDD bq77905 VC2 RIN CIN RIN RTS TS VC1 CIN RTS_PU VTB LD AVSS CHG SRP CHGU SRN DSG VDD DVSS AVDD CTRD VC5 CTRC VC4 CCFG CIN RVDD CVDD CVDD RIN CIN RIN RIN RIN RIN VC3 CIN VC2 VC1 CIN CIN bq77905 RCTRD RCTRC RTS_PU VTB RTS TS LD AVSS CHG SRP CHGU SRN DSG RCHG RDSG RLD CIN RGS_DSG RGS_CHG RSNS PACK- Figure 17. 10S Pack Using Two bq77905 Devices Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 23 bq77904, bq77905 SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 www.ti.com PACK+ RVDD CVDD RIN CVDD CIN RIN CIN VDD DVSS AVDD CTRD VC5 CTRC VC4 CCFG VC3 RIN CIN bq77905 VC2 CIN RIN CIN RTS TS VC1 RIN RTS_PU VTB LD AVSS CHG SRP CHGU SRN DSG RVDD CVDD CVDD RIN CIN RIN DVSS CTRD VC5 CTRC VC4 CCFG VTB VC3 CIN RIN VDD AVDD bq77905 VC2 CIN RIN RTS_PU RTS LD AVSS RIN RCTRC TS VC1 CIN RCTRD CHG SRP CHGU SRN DSG CIN RVDD CVDD CVDD VDD DVSS AVDD CTRD VC5 CTRC VC4 CCFG VTB VC3 VC2 RIN RIN RIN VC1 CIN CIN bq77905 RCTRD RCTRC RTS_PU RTS TS LD AVSS CHG SRP CHGU SRN DSG RCHG RDSG RLD CIN RGS RGS RSNS PACK- Figure 18. 13S Pack Using Three bq77905 Devices 24 Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 bq77904, bq77905 www.ti.com SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 8.3.12 Zero-Volt Battery Charging Inhibition Once the device is powered up, it can pull the CHG pin up if the VDD ≥ VSHUT, which varies from about 1 V per cell on a 3S configuration to about 0.6 V per cell on a 5S configuration. If the battery stack voltage falls below VSHUT, the device is in SHUTDOWN mode and the CHG driver is not longer active and charging is not allowed unless VDD rises above VPOR again. 8.4 Device Functional Modes 8.4.1 Power Modes 8.4.1.1 Power On Reset (POR) The device powers up when VDD ≥ VPOR. At POR, the following events occur: • A typical 5-ms hold-off delay applies to both CHG and DSG drivers, keeping both drivers in the OFF state. This provides time for the internal LDO voltage to ramp up. • CTRC and CTRD de-glitch occurs. During the de-glitch time, the CHG and DSG driver remains off. Note that de-glitch time basically mask out the 5-ms hold-off delay. • Device assumes OV fault at POR, hence, the CHG driver is off for OV recovery time if all the cell voltages are < (VOV – VHYS_OV). The OV recovery time start after the 5-ms hold-off delay. If device reset occurs when any cell voltage is above the OV hysteresis range, the CHG driver will remain off until an OV recovery condition is met. 8.4.1.2 FAULT Mode If any configured protection fault is detected, the device enters the FAULT mode. In this mode, the CHG and/or DSG driver can be turned off depending on the fault. Refer to the Fault Response Summary for detail. When one of the FET drivers (either CHG or DSG) is turned off, while the other FET driver is still on, the state comparator is activated for FET body diode protection. 8.4.1.3 SHUTDOWN Mode This is the lowest power consumption state of the device when VDD falls below VSHUT. In this mode, all fault detections, CHG and DSG drivers are disabled. The device will wake up and enter NORMAL Mode when VDD rises above VPOR. 8.4.1.4 Customer Fast Production Test Modes The bq7790x device supports the ability to greatly reduce production test time by cutting down on protection fault delay times. To shorten fault times, place the bq7790x device into Customer Test Mode (CTM). CTM is triggered by raising VDD to VCTM voltage above the highest cell input pin (that is, VC5) for tCTM_ENTRY time. The CTM is expected to be used in single-chip designs only. CTM is not supported for stacked designs. Once the device is in CTM, all fault delay and non-current fault's recovery delay times reduce to a value of tCTM_DELAY. The fault recovery time for overcurrent faults (OCD1, OCD2, and SCD) is reduced to tCTM_OC_REC. Verification of protection fault functionality can be accomplished in a reduced time frame in CTM. Reducing the VDD voltage to the same voltage applied to the highest-cell input pin for tCTM_ENTRY will exit CTM. In CTM, with reduced time for all internal delays, qualification of all faults will be reduced to a single instance. Thus in this mode, fault condition qualification is more susceptible to transients, so take care to have fault conditions clearly and cleanly applied during test mode to avoid false triggering of fault conditions during CTM. Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 25 bq77904, bq77905 SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 www.ti.com 9 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality. 9.1 Application Information The bq77904 and bq77905 are low power stackable battery pack protectors with integrated low-side NMOS FET driver. The bq77904 and bq77905 provides voltage, current, temperature and open wire protections. All the devices protect and recover without a MCU control. The following section highlights several recommended implementation when using these devices. 9.1.1 Recommended System Implementation 9.1.1.1 CHG and DSG FET Rise and Fall Time The CHG and DSG FET driver are designed to have fast switching time. Customer should select a proper gate resistor (RCHG and RDSG in the reference schematic) to set to the desired rise/fall time. DSG CHG Select proper gate resistor to adjust the desired rise/ fall time RCHG RDSG RGS_DSG RGS_CHG Q2 Q1 RSNS PACK- Figure 19. Select Proper Gate Resistor for FET Rise and Fall Time The CHG FET fall time is generally slower because it is connected to the PACK- terminal. The CHG driver will pull to VSS quickly when the driver is signaled to turn off. Once the gate of the CHG FET reaches ground or Vgsth, the PACK- will start to fall below ground, the CHG signal will follow suit in order to turn off the CHG FET. This portion of the fall time is strongly dependent on the FET characteristic, the number of FETs in parallel, and the value of gate-source resistor (RGS_CHG). 26 Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 bq77904, bq77905 www.ti.com SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 Application Information (continued) Strong pull down by the CHG driver when the device is initially signaled to turn off CHG. Once the CFET gate voltage reach PACK-, PACKvoltage starts to fall below ground. The gate voltage is then relying on RGS_CHG to fall with PACK- to keep the CHG FET off. Figure 20. CHG FET Fall Time 9.1.1.2 Protecting CHG And LD Because both CHG and LD are connected to PACK- terminal, these pins are specially designed to sustain an absolute max of -30 V. However, the device can be used in a wide variety of application, it is possible to expose the pins lower than –30 V absolute max rating. To protect the pins, TI recommends to put a PMOS FET in series of the CHG pin and a diode in series of the LD pin as shown below. DSG CHG LD Q3 and the LD pin diode are used to keep CHG and LD away from any voltages below VSS. Apply these components when CHG and LD pins can be exposed beyond the absolute -30V. Q3 RDSG RCHG RLD RGS_DSG RGS_CHG Q2 Q3 will allow RGS_CHG to keeps Q1 OFF, since all voltages below this FET can ^(}oo}Á_ W <- as it goes below VSS. Q1 RSNS PACK- Figure 21. Protect CHG and LD Go Below Absolute Minimum 9.1.1.3 Protecting CHG FET When CHG driver is off, CHG is pulled to VSS, the PACK- terminal can be pull up to PACK+ level when a load is connected. This can put the gate-source voltage above the absolute max of the MOSFET rating. Hence, it is common to place a Zener diode across the CHG FET’s gate-source to protect the CHG FET. Additional components are added when a Zener is used to limit current going into the CHG pin as well as reducing the impact on rise time. See Figure 22 for details. Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 27 bq77904, bq77905 SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 www.ti.com Application Information (continued) DSG CHG RDSG This diode allows CHG to pull the Q1 gate high, bypassing the path through RCHG and RGS_CHG which will divide down the CHG ON voltage RCHG drops the voltage and limits the current going into the CHG pin when RCHG PACK- is pulled high and zener across Q1 (1MŸ ) Vgs is used. RGS_CHG (>=1MŸ) RGS_DSG Q2 This zener clamp may be needed to prevent the Vgs of Q1 excesses absolute max rating. Q1 16V RSNS PACK- Figure 22. Protect CHG FET from High Voltage on PACK– DSG LD CHG Q3 RCHG (1MŸ ) RDSG RGS_DSG Q2 Q1 RLD RGS_CHG (>=1MŸ) 16V RSNS PACK- Figure 23. Optional Components Combining Figure 21 and Figure 22 Protections 9.1.1.4 Using Load Detect For UV Fault Recovery A larger CHG FET gate-source resistor is required if load removal is enabled as part of the UV recovery criteria. When the load removal circuit is enabled, the device is internally connected to Vss. Because in UV fault, the CHG driver remains on, it creates a resistor divider path to the load detect circuit. 28 Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 bq77904, bq77905 www.ti.com SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 Application Information (continued) PACK+ bq77094/5 Load Detect block VLDT LD pin RLD_INT FET driver block VFETON LOAD CHG pin RCHG RLD 16V CFET RGS_CHG PACKFigure 24. Load Detect Circuit During UV Fault To ensure load removal is detected properly during UV fault, TI recommends to use 3.3 MΩ for RGS_CHG (instead of a typical of 1 MΩ when load removal is NOT required for UV recovery). RCHG can stay in 1 MΩ as recommended when using CHG FET protection components. The CHG FET rise time impact is minimized as described in the “Protecting CHG FET” section. On a stacked configuration, connect the LD pin as shown in Figure 25 if load removal is used for UV fault recovery. If load detection is not required for UV fault recovery, a larger value of RGS_CHG can be used (that is, 10 MΩ) and there LD pin on the upper devices can be left floating. Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 29 bq77904, bq77905 SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 www.ti.com Application Information (continued) bq77094/5 LD pin Upper device Vss pin Ra is used to keep the LD pin pull down when load detect circuit is not activated Ra (1M) Must have block diode on the upper device. RLD bq77094/5 LD pin Bottom device Vss pin RLD Diode for the bottom device is optional. Use if the LD pin will be exposed lower than -30V. PACKFigure 25. Simplified Circuit: LD Connection On Upper Device When Using For UV Fault Recovery 9.1.1.5 Temperature Protection The device detects temperature by checking the voltage divided by RTS_PU and RTS, with the assumption of using 10 KΩ RTS_PU and 103AT NTC for RTS. System designer should always check the thermistor resistance characteristic and refer to the temperature protection threshold specification in the Electrical Characteristic table to determine if a different pull up resistor should be used. If a different temperature trip pint is required, it is possible to scale the threshold using this equation: Temperature Protection Threshold = RTS/(RTS + RTS_PU). Example: Scale OTC trip points from 50°C to 55°C The OTC protection can be set to 45°C or 50°C. When the device's OTC threshold is set to 50°C, it is referred to configure the VOTC parameter to 29.38% of VTB (typical), with the assumption of RTS_PU = 10KΩ and RTS = 103AT or similar NTC (which the NTC resistance at 50°C = 4.16 KΩ). The VOTC specification is simply the resistor divider ratio of RTS_PU and RTS. The VOTC, VOTD, VUTC and VUTD configuration options are fixed in the device. Hence, the actual temperature trip point can only adjust by using a different B-value NTC and/or using a different RTS_PU. In this example, the 103AT NTC resistance at 55°C is 3.536 KΩ. By changing the RTS_PU from 10 KΩ to 8.5 KΩ, we can scale the actual OTC temperature trip point from 50°C to 55°C. Because the RTS_PU value is smaller, this change affects all the other temperature trip points and scales OTD, UTC and UTD to ~5°C higher as well. 9.1.1.6 Adding Filter to Sense Resistor Current fault is sense through voltage across sense resistor. Optional RC filters can be added to the sense resistor to improve stability. 30 Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 bq77904, bq77905 www.ti.com SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 Application Information (continued) SRP 0.1 µF SRN 0.1 µF 100 Ÿ 0.1 µF 100 Ÿ R SNS PACK- Figure 26. Optional Filters Improve Current Measurement 9.1.1.7 Using State Comparator In Application The state comparator does not have built-in hysteresis. It is normal to observe the FET body diode protection toggling on and off with the VSTATE_C1 or VSTATE_D1 accuracy range. In a typical application, the sense resistor is selected according to the application current, which usually is not close to the state comparator threshold. 9.1.1.7.1 Examples For example, using a 5-Ah battery, with 1C-rate (5 A) charge and 2C-rate (10 A) discharge, the sense resistor is mostly 3 mΩ or less. The typical current to turn on the FET body diode protection is 667 mA using this example. Because there is no built-in hysteresis, noise can reset the state comparator counter and toggle off the FET body diode protection and vice versa. Hence, it is normal to observe the device toggles the FET body diode protection on or off within 1 mV to 3 mV range. With a 3mohm sense resistor, it is about 330 mA to 1 A. As this behavior is due to noise from the system, the FET toggling behavior is usually occurs right at the typical 2mV state comparator threshold, as current increases or decreases from the typical value, the detection is more solid and has less frequent FET toggling. Using this example, either charge or discharge should provide a solid FET body diode protection detection. Look at the device behavior during an OV event (and no other fault is detected). In an OV event, CHG FET is off and DSG FET is on. If a discharge of >1 A occurs, the device would turn on the CHG FET immediate to allow the full discharge current to pass through. Once the overcharged cell is discharged to the OV recovery level, the OV fault is recovered and CHG driver turns on (or remains on in this scenario) and the state comparator is turned off. If the discharge current is < 1 A when the device is still in OV fault, the CHG FET may toggle on and off until the overcharged cell voltage is reduced down to the OV recovery level. When OV fault recovered, the CHG FET will be solidly turned on and the state comparator is off. Without the FET body diode protection, if a discharge occurs during an OV fault state, the discharge current can only pass through the CHG FET body diode until the OV fault is recovered. This increase the risk of damaging the CHG FET if the MOSFET is not rate to sustain such current through its body diode. It also increases the FET temperature as current is now carry through the body diode. Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 31 bq77904, bq77905 SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 www.ti.com 9.2 Typical Application PACK+ RVDD CVDD CVDD VDD DVSS AVDD CTRD VC5 CTRC VC3 CIN VC2 RIN RIN RIN CCFG VC4 RIN bq77905 bq77904 CIN RTS TS VC1 CIN RTS_PU VTB LD AVSS CHG SRP CHGU SRN DSG RCHG RDSG RLD CIN RGS RGS RSNS PACKCopyright © 2016, Texas Instruments Incorporated Figure 27. bq77904 and bq77905 With 4 Cells 9.2.1 Design Requirements For this design example, use the parameters shown in Table 9. Table 9. Design Parameters PARAMETER DESCRIPTION VALUES RIN Cell voltage sensing (VCx pins) filter resistor CIN Cell voltage sensing (VCx pins) filter capacitor 1 kΩ ±5% RVDD Supply voltage filter resistor CVDD Supply voltage filter capacitor RTS NTC thermistor RTS_PU Thermistor pullup resistor to VTB pin, assuming using 103AT NTC or NTC with similar resistance-temperature characteristic RGS_CHG CHG FET gatesource resistor 0.1 µF ±10% 1 kΩ ±5% 1 µF ±20% 103AT, 10 kΩ ±3% 10 kΩ ±1% Load removal is enabled for UV recovery 3.3 MΩ ±5% Load removal is disabled for UV recovery 1 MΩ ±5% RGS_DSG DSG FET gate-source resistor RCHG CHG gate resistor 1 MΩ ±5% system designer should adjust this parameter to meet the desirable FET rise/fall time 1 kΩ ±5% If additional components are used to protect the CHG FET and/or to enable load removal detection for UV recovery 1 MΩ ±5% RDSG DSG gate resistor, system designer should adjust this parameter to meet the desirable FET rise/fall time 4.5 kΩ ±5% RCRTC and RCTRD CTRC and CTRD current limit resistor 10 MΩ ±5% RLD LD resistor for load removal detection 450 KΩ ±5% RSNS Current sense resistor for current protection , system designer should change this parameter according to the application current protection requirement 32 Submit Documentation Feedback 1 mΩ ±1% Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 bq77904, bq77905 www.ti.com SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 9.2.2 Detailed Design Procedure The following is the detailed design procedure. 1. Based on the application current, select the proper sense resistor value. The sense resistor should allow detection of the highest current protection, short circuit current. 2. Temperature protection is set with the assuming of using 103AT NTC (or NTC with similar specification). If a different type of NTC is used, a different RTS_PU may be used for the application. Refer to the actual temperature detection threshold voltage to determine the RTS_PU value. 3. Connect the CCFG pin correctly based on the number of cell in series. 4. Review the Recommended Application Implementation to determine if optional components should be added to the schematic. 9.2.2.1 Design Example To design the protection for a 36 V Li-ion battery pack using 4.2 V LiCoO2 cells with the following protection requirements. Voltage Protection • OV at 4.3 V, recover at 4.1 V • UV at 2.6 V, recover at 3 V and when load is removed Current Protection • OCD1 at 40 A with 300-400 ms delay • OCD2 at 80 A with the shortest delay option • SCD at 100 A with < 500 us delay • Requires load removal for recovery Temperature Protection • Charge - OTC at 50°C, UTC at –5°C • Discharge - OTD at 70°C, UTD at –10°C To start the design: 1. Start the schematic – A 36-V pack using LiCoO2 cells requires 10S configuration. Hence, two bq77905 devices in stackable configuration is needed. – Follow the 10 S reference schematic in this document. Follow the recommended design parameters list in the Design Requirements section of this document. – The power FET uses in this type of application usually has an absolute of 20 V Vgs. For a 36-V pack design, TI recommends to use the additional components to protect the CHG FET Vgs. See the Using Load Detect For UV Fault Recovery section for detail. – Because load removal for UV recovery is required, a 3 MΩ RGS_CHG should be used for the schematic. 2. Decide the value of the sense resistor, RSNS – When selecting the value of RSNS, ensure the voltage drop across SRP and SRN is within the available current protection threshold range. – In this example, select RSNS = 1 mΩ (any value ≤ 2 mΩ will work in this example). 3. Determine all the bq77905 protection configuration, see Table 10. 4. Review the available release or preview device in the Device Comparison section to determine if a suitable option is available. If not, contact TI representative for further assistant. Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 33 bq77904, bq77905 SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 www.ti.com Table 10. Design Example Configuration Protection Threshold Hystersis Delay Recovery Method OV 4.3 V 200 mV 1 s (default setting) Hysteresis UV 2.6 V 400 mV 1 s (default setting) Hysteresis + load removal OW 100 nA (default setting) - - (VCx - VCx-1) > 600 mV (typical) OCD1 40 mV - 350 ms Load removal only OCD2 80 mV - 5 ms Load removal only SCD 100 mV - Fixed at 360 us Load removal only OTC 50°C 10°C 4.5 s Hysteresis OTD 70°C 10°C 4.5 s Hysteresis UTC –5°C 10°C 4.5 s Hysteresis UTD –10°C 10°C 4.5 s Hysteresis 34 Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 bq77904, bq77905 www.ti.com SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 9.2.3 Application Curves DSG remains on DSG remains on CHG recovers after 2nd OV fault is removed CHG falls due to detection of 1st OV fault Figure 28. OV Fault Protection State comparator detects discharge and turns CHG back on even OV fault is present 2nd Fault removed 1st Fault removed 1st OV Fault Figure 29. OV Fault Recovery Device is set to recovery after current recovery delay. Both CHG/DSG turns back on, but device detects OCD2 fault and turns off both FET driver again Both CHG/DSG are off in OCD2 fault CHG falls due to OV fault. State comparator is on to detect any discharge activity OV fault OCD2 fault inserted Figure 31. Detect OTC Fault While in 30A Discharge Figure 30. OV and OCD2 Faults Protection DSG falls due to UV fault on VC2 DSG falls after ~ 1s due to UV fault on VC2 In real application, OV and UV are usually triggered first in an open wire event, masking out the OW protection. This capture is to demonstrate the OW protection by observing the CHG delay time CHG falls after ~5s due to OW CHG falls after ~ 1s due to OV fault on VC3 Relay opens ± open cell2 to pcb connection VC2 ramped to 0V, while other cell voltages stay in normal In real application, an open wire event will deplete the filter capacitor connects to the device cell voltage sensing pin. The depleted capacitor will trigger the UV fault. It also causes the upper cell voltage sensing pin to see a sum of 2 cell voltages, which will trigger an OV fault. OV and UV delays are shorter than OW delay, hence, the OV and UV will triggered before OW protection activates. Figure 32. OW Fault Protection - Open Cell2 To PCB Connection Figure 33. OW Fault Protection - Ramping Down Cell2 Voltage Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 35 bq77904, bq77905 SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 www.ti.com 9.3 System Examples PACK+ RVDD CVDD RIN RIN RIN RIN RIN CVDD CIN CIN CIN CIN VDD DVSS AVDD CTRD VC5 CTRC VC4 CCFG VC3 VTB bq77905 VC2 TS VC1 LD AVSS CHG SRP CHGU SRN DSG RTS_PU RTS RCHG RDSG RLD CIN RGS RGS RSNS PACKCopyright © 2016, Texas Instruments Incorporated Figure 34. bq77905 With 5 Cells 10 Power Supply Recommendations The recommended cell voltage range is up to 5 V. If 3 cells in series is connecting to bq77905, the unused VCx pins should be shorted to the highest unused VCx pin. The recommended VDD range is from 3 V to 25 V. This implies the device is still operational when cell voltage is depleted down to approximately 1.5 V range. 36 Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 bq77904, bq77905 www.ti.com SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 11 Layout 11.1 Layout Guidelines 1. Match SRN and SRP trace. 2. RIN filters, VDD, AVDD filters and CVDD capacitor should be placed close to the device pins. 3. Separating device ground plane (low current ground) from the high current path. Filter capacitors should reference to the low current ground path or device Vss. 4. In a stack configuration, the RCTRD and RCTRC should be placed closer to the lower device CTRD and CTRC pins. 5. RGS should be placed near the FETs 11.2 Layout Example High current Path Please filters close to IC pins VDD DVSS Connect AVSS and DVSS to device ground plane AVDD RC Filters PACK+ VC5 : : Low current, local ground for each device VC1 AVSS AVSS CHGU DSG Connect the device ground at šZ o}Á Œ oo[• oo- on each cell group Please filters close to IC pins VDD AVDD RC Filters VC5 : : DVSS DVSS CTRD Please CTRs resistors close to the lower device CTRC VC1 AVSS AVSS Connect the bottom device ground at BAT-. Using BAT- as the mutual point to connect high and low current path Low current, local device ground. Separate from high power path PACK- Figure 35. Layout Example Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 37 bq77904, bq77905 SLUSCM3E – JUNE 2016 – REVISED MARCH 2017 www.ti.com 12 Device and Documentation Support 12.1 Documentation Support 12.1.1 Related Links The table below lists quick access links. Categories include technical documents, support and community resources, tools and software, and quick access to order now. Table 11. Related Links PARTS PRODUCT FOLDER ORDER NOW TECHNICAL DOCUMENTS TOOLS & SOFTWARE SUPPORT & COMMUNITY bq77904 Click here Click here Click here Click here Click here bq77905 Click here Click here Click here Click here Click here 12.2 Receiving Notification of Documentation Updates To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper right corner, click on Alert me to register and receive a weekly digest of any product information that has changed. For change details, review the revision history included in any revised document. 12.3 Community Resources The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use. TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help solve problems with fellow engineers. Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and contact information for technical support. 12.4 Trademarks E2E is a trademark of Texas Instruments. All other trademarks are the property of their respective owners. 12.5 Electrostatic Discharge Caution 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. 12.6 Glossary SLYZ022 — TI Glossary. This glossary lists and explains terms, acronyms, and definitions. 13 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. 38 Submit Documentation Feedback Copyright © 2016–2017, Texas Instruments Incorporated Product Folder Links: bq77904 bq77905 PACKAGE OPTION ADDENDUM www.ti.com 3-May-2017 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish MSL Peak Temp (2) (6) (3) Op Temp (°C) Device Marking (4/5) BQ7790400PW ACTIVE TSSOP PW 20 70 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 B7790400 BQ7790400PWR ACTIVE TSSOP PW 20 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 B7790400 BQ7790500PW ACTIVE TSSOP PW 20 70 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 B7790500 BQ7790500PWR ACTIVE TSSOP PW 20 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 B7790500 BQ7790501PW PREVIEW TSSOP PW 20 70 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 B7790501 BQ7790501PWR PREVIEW TSSOP PW 20 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 B7790501 BQ7790502PW ACTIVE TSSOP PW 20 70 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 B7790502 BQ7790502PWR ACTIVE TSSOP PW 20 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 B7790502 BQ7790503PW ACTIVE TSSOP PW 20 70 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 B7790503 BQ7790503PWR ACTIVE TSSOP PW 20 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 B7790503 BQ7790505PW ACTIVE TSSOP PW 20 70 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 B7790505 BQ7790505PWR ACTIVE TSSOP PW 20 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 B7790505 BQ7790508PW PREVIEW TSSOP PW 20 70 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 B7790508 BQ7790508PWR PREVIEW TSSOP PW 20 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 B7790508 BQ7790509PW PREVIEW TSSOP PW 20 70 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 B7790509 BQ7790509PWR PREVIEW TSSOP PW 20 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR -40 to 85 B7790509 (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. Addendum-Page 1 Samples PACKAGE OPTION ADDENDUM www.ti.com 3-May-2017 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 <=1000ppm threshold. Antimony trioxide based flame retardants must also meet the <=1000ppm threshold requirement. (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish value exceeds the maximum column width. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 4-May-2017 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant BQ7790400PWR TSSOP PW 20 2000 330.0 16.4 6.95 7.1 1.6 8.0 16.0 Q1 BQ7790500PWR TSSOP PW 20 2000 330.0 16.4 6.95 7.1 1.6 8.0 16.0 Q1 BQ7790502PWR TSSOP PW 20 2000 330.0 16.4 6.95 7.1 1.6 8.0 16.0 Q1 BQ7790503PWR TSSOP PW 20 2000 330.0 16.4 6.95 7.1 1.6 8.0 16.0 Q1 BQ7790505PWR TSSOP PW 20 2000 330.0 16.4 6.95 7.1 1.6 8.0 16.0 Q1 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 4-May-2017 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) BQ7790400PWR TSSOP PW 20 2000 367.0 367.0 38.0 BQ7790500PWR TSSOP PW 20 2000 367.0 367.0 38.0 BQ7790502PWR TSSOP PW 20 2000 367.0 367.0 38.0 BQ7790503PWR TSSOP PW 20 2000 367.0 367.0 38.0 BQ7790505PWR TSSOP PW 20 2000 367.0 367.0 38.0 Pack Materials-Page 2 IMPORTANT NOTICE Texas Instruments Incorporated (TI) reserves the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. 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