Preliminary bq2148 Smart Battery Module with LEDs and Pack Supervisor Features ä Complete smart battery management solution for Li-Ion battery packs ä Accurate measurement of available battery capacity ä Provides overvoltage, undervoltage, and overcurrent protection ä Designed for battery pack integration: – Small size – I ncl ud e s b q 2 0 4 0 a nd b q 2 0 5 8 I C s, a n d configuration EEPROM – On-board charge and discharge control FETs – Low operating current for minimal battery drain ä Critical battery information available over two-wire serial port ä "L” version includes 4 push-button activated LEDs to display state-of-charge information Unitrode configures the bq2168 based on the information requested in Table 1. The configuration defines all the EEPROM parameters and the protection threshold. Figure 1 shows how the module connects to the cells. The bq2148L includes four LEDs to display remaining capacity in 25% increments of the learned capacity. The LEDs are activated with the onboard push-button switch. A module development kit is also available for the bq2148. The bq2148B-KT or the bq2148LB-KT includes one configured module and the following: General Description The bq2148 Smaart Battery Module provides a complete and compact battery management solution for Li-Ion battery packs. Designed for battery pack integration, the bq2168 combines the bq2040H Gas Gauge IC with the bq2058 Supervisor IC on a small printed circuit board. The board includes all the necessary components to accurately monitor battery capacity and protect the cells from overvoltage, undervoltage, and overcurrent conditions. The board works with three or four Li-Ion series cells. 1) An EV2200-40 interface board that allows connection to the serial port of any AT-compatible computer. 2) Menu driven software to display charge/discharge activity and to allow user interface to the bq2040 from any standard Windows 3.1x or 95 PC. Pin Descriptions The Gas Gauge IC uses the on-board sense resistor to track charge and discharge activity of the battery pack. Critical battery information can be accessed through the serial communications port at SMBC/SMBD. The bq2148 uses the SMBus communications protocol and supports the Smart Battery Data Commands in the SBD specification. The supervisor circuit consists of the bq2058 and two FETs. The bq2058 controls the FETs to protect the batteries during charge/discharge cycles and short circuit conditions. The bq2168 provides contacts for the positive and negative terminals of each battery in the stack. Please refer to the bq2040 and bq2058 data sheets for the specifics on the operation of the power gauge and supervisor ICs. 5/99 1 POS PACK+/Pack positive NEG PACK-/Pack negative SMBC Communications clock SMBD Serial data ITEST Overcurrent test input B1P Battery 1 positive input B1N Battery 1 negative input B2N Battery 2 negative input B3N Battery 3 negative input B4N Battery 4 negative input Preliminary bq2148 Table 1. bq2148 Module Configuration Customer Name: ______________________________________________________________________________________________ Contact: _______________________________________________________ Phone:____________________________ Address:________________________________________________________________________________________________ Sales Contact: __________________________________________________ Phone: ____________________________ Board Configuration LEDs and switch ________________ Yes or No Display mode ________________ Relative or Absolute Discharge current (3.9A max.) Min ____________ Avg ____________ Duration at max. discharge ________________ Overvoltage threshold (4.25, 4.30, or 4.35V) ____________________________ Number of series cells _________________ EEPROM Configuration Remaining time alarm (min) Remaining capacity alarm (mAh) Charging voltage (mV) Design cpaacity (mAh) Design voltage (mV) Manufacturer date Serial number Fast-charging current (mA) Maintenance charging current (mA) Li-Ion taper current (mA) Maximum overcharge (mAh) Max ___________ _______________ Sets the low time alarm level _______________ Sets the low capacity alarm level _______________ _______________ _______________ _______________ _______________ _______________ _______________ _______________ _______________ _______________ Sets the requested charging voltage Defines the battery pack capacity Defines the battery pack voltage Battery pack manufacturer date Battery pack serial number Sets the requested charging current Sets the requested maintenance charging current Sets the upper limit for charge termination Sets the maximum amount of overcharge Sets the maximum charge temperature ∆T/∆t (°C/min) Fast-charge efficiency (%) Maintenance charge efficiency (%) Self-discharge rate (%/day) EDV1 (mV) EDVF (mV) _______________ _______________ Sets the termination rate Sets the fast-charge efficiency factor _______________ Sets the maintence charge efficiency factor _______________ _______________ _______________ Sets the batterys self-discharge rate Sets the initial end-of-discharge warning Sets the final end-of-discharge warning Hold-off timer for ∆T/∆t (sec.) _______________ Manufacturer name Device name Chemistry Manufacturer data FAE approval: _______________ _______________ _______________ _______________ _______________ Maximum temperature (°C) Typical Values 10 min C/10 4.1V/cell 3600 10800 mm/dd/yy 0-65535 1C 0 C/10 128mAh 61°C 4.6°C/20s 100% 100% 0.2%/day 3.0V/cell 2.8V/cell Sets the hold off period for ∆T/∆t 320s termination Programs manufacturer’s name (11 char. max) bq Programs device name (7 char. max) bq202 Programs pack’s chemistry (5 char. max) LION Open field (5 char. max) 2040 Date: ________________ 2 bq2148 Preliminary Battery Pack Cells B4N B3N B2N B1N B1P bq2148 NEG POS PACK- PACK+ Load Charger FG2148-1.eps Figure 1. Module Connection Diagram B1P NC B1P POS B1N B1N Load or Charger B2N Load or Charger B2N B3N B3N B4N POS B4N NEG NEG Four-Cell Configuration Three-Cell Configuration Note: B1P, B4N, POS, and NEG accomodate a #20 AWG stranded wire. B1N, B2N, and B3N accomodate a #24 AWG stranded wire. FG2158cc.eps Figure 1. Module Connection Diagram Absolute Maximum Ratings Symbol VOP Parameter Supply voltage (B1P to B4N) Value Unit 18 V DC Maximum duration = 1.5µs VTR Maximum transient voltage (B1P to B4N) 32 V VCHG Charging voltage (POS to NEG) 18 V ICHG Continuous charge/discharge current 3.9 A TOPR Operating temperature 0 to +70 °C TSTG Storage temperature -55 to +125 °C Note: Conditions VOP > 6V TA = 25°C Permanent device damage may occur if Absolute Maximum Ratings are exceeded. Functional operation should be limited to the Recommended DC Operating Conditions detailed in this data sheet. Exposure to conditions beyond the operational limits for extended periods of time may affect device reliability. 3 Preliminary bq2148 bq2148 Schematic 1 2 3 Component values depend on user-provided information in Table 1. 33153f_1.eps 4 bq2148 Preliminary bq2148 Schematic (Continued) 33153f_2.eps 5 Preliminary bq2148 bq2148 Board DS2148_F.eps 6 bq2148 Preliminary DC Electrical Characteristics (TA = TOPR) Symbol Parameter Minimum Typical Maximum Unit 4.0 - 18 V VOP Operating voltage, B1P to B4N ICCA Operating current - - 350 µA RON On resistance, B1P to POS - - 50 mΩ Conditions/Notes TA = 25°C, VOP = 10V DC Thresholds (TA = TOPR) Symbol Parameter Value Tolerance Unit VOV Overvoltage threshold 4.25 ± 50mV V VCE Charge enable voltage VOV - 100mV ± 50mV V VUV Undervoltage limit 2.25 ± 100mV V 3.4 IOC Overcurrent limit tUVD Undervoltage delay A 3.8 Notes TA = 25°C A TA = 60°C 950 ±50% ms TA = 30°C VCD Charge detect threshold 70 -60, +80 mV tOVD Overvoltage delay 950 ±50% ms TA = 30°C tOCD Overcurrent delay 12 ±60% ms TA = 30°C Note: The thresholds above reflect the operation of a bq2148 using the standard bq2058 IC (VOV = 4.25V). Specify other versions of the bq2058 by indicating the appropriate VOV threshold in Table 1. Ordering Information bq2148 B — Customer Code: Blank = Sample or Pre-production1 KT = Evaluation system XXX = Customer-specific; assigned by Unitrode2 Package Option: B = Board-level product LED Option: L = LEDs plus switch Blank = No LEDs or switch Device: Smart Battery Module with LEDs and Pack Supervisor Notes: 1. Requires configuration sheet (Table 1) 2. Example production part number: bq2148LB-001 7 IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. 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