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Details, datasheet, quote on part number:EV2014X
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| Part: | EV2014X |
| Category: | Others |
| Description: | Gas Gauge With 1-WIRE (DQ) Interface, 5 Led Drivers And Control Signals For The BQ2004 Fast Charge i |
| Company: | Texas Instruments, Inc. |
| Datasheet: | Download EV2014X datasheet File size : 148 kB |
| Request For quote: | Find where to buy EV2014X
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Datasheet text preview:
EV2014x
Gas Gauge and Fast Charge Evaluation Board
Introduction
The EV2014x evaluation system provides a development and evaluation environment for the bq2014 Gas Gauge IC and the bq2004 Fast Charge IC. The EV2014x incorporates a bq2014, a bq2004, and all the external components required to accurately monitor the capacity and reliably fast charge 4 to 10 NiCd or NiMH cells. The evaluation system includes a PC/AT interface to allow the monitoring of battery parameters. The board features:
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Jumper configuration for number of series cells and battery chemistry Complete fast charge control Battery capacity monitoring - LED display of available charge
Functional Description
The EV2014x provides two main functions: fast charge control and battery capacity monitoring. The actual implementation of a bq2004/bq2014 design will be significantly smaller in size. See the bq2004 and the bq2014 data sheets for device functional descriptions. Battery fast charge is terminated by any of the following: T/t (the change in temperature versus time), -V (negative voltage change) or PVD (peak voltage detect), maximum temperature, maximum time, and maximum voltage. The board provides a direct connection for an NTC thermistor for temperature charge terminations and safety qualifications. It also includes an RS232 interface for easy access to the battery state of charge information via the serial port of the bq2014. The menu driven gas gauge software provided displays charge/discharge activity and allows user interface to the bq2014 from any standard DOS PC. The user supplies the power supply and the batteries. Onboard LEDs indicate charging status and remaining capacity. The capacity LEDs are activated by the push button switch. Table 4 in the application note entitled "Using the bq2010-A Tutorial for Gas Gauging" for a more detailed description of the bq2014 voltage regulator.
Current Path
The bq2014 uses a sense resistor (R16) on the negative terminal of the battery to measure charge and discharge activity. This resistor may be changed if necessary. The system load is connected between the BAT+ (J1) and PACK-(J2) terminal blocks (see the schematic in Appendix C). During charge, the bq2004 buck mode regulator also uses a sense resistor to regulate the charge current. The board is shipped with a value of 0.100ohm which corresponds to a charge current of 2.25A. This resistor can be changed depending on the application.
Parameter Programming
The EV2014x is programmed with jumpers JP1-JP3 and JP6-JP10. The programming pins determine:
Power Source
An onboard voltage regulator supplies the bq2004 fast charge chip with power from the DC charge input. The bq2014 derives its VCC from the battery connected to the BAT+ (J1) and BAT- (J2) terminal blocks. The bias resistor (R17) for the bq2014 voltage regulator is 300K. For less than 6 cells, this value should be 100K. Refer to
Dec. 1996
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Charge timeout limits Fast charge termination mode Programmed full count Scale factor Self-discharge rate
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EV2014x EV2014x Contents
Each package contains the following items: 1 EV2014x PC Board This includes the bq2014 sample, current regulators, programming jumpers, battery divider resistors, and the PC serial port interface. 1 1 EV2014x DQ/RS-232 Cable EV2014x (v2.0) User Interface Program Diskette This program runs on any AT-compatible computer equipped with a standard RS-232 (COM1, COM2, COM3, or COM4) serial port, and provides the user with a complete menu-driven system to control, monitor, and log data from the EV2014xx Evaluation Board. The User Interface Program communicates with the bq2014 over the DQ serial I/O port using the RS-232 interface. Please check to make sure that all items are present and in good condition. If you have any problems, please contact your Benchmarq representative or call Benchmarq. Charge initiates on the later application of the battery or DC, which provides VCC to the bq2004. As shipped from Benchmarq, the EV2014x buck-type switch-mode regulator is configured to a charging current of 2.25A. This current level is controlled by the value of sense resistor RSNS by the relationship: ICHG = 0.225V RSNS
The value of RSNS at shipment is 0.100. This resistor can be changed depending on the application. The suggested maximum ICHG for the EV2014x board is 3A. The maximum cell voltage (MCV) setting is 1.8V. The EV2014x gas gauge uses a 0.100 sense resistor to measure charge and discharge current. Zener diode D11 is used to limit Q4 VGS per a given DC voltage. The board is shipped with D5 shorted. The user can modify this Zener diode for the application. Refer to Table 1 for suggested D5 values for DC voltages. With the provided NTC thermistor connected between THERM and SNS, values are: LTF = 10°C, HTF = 45°C, and TCO = 50°C. The T/t settings at 30°C (Tt) are: minimum = 0.82°C/minute, typical = 1.10°C/minute. The thermistor is identified by the serial number suffix as follows:
EV2014x Connections
The connections for the EV2014x are described below. Please refer to the attached schematic in conjunction with these descriptions. JP16 JP2 JP3 JP4, JP12 JP5, JP13 JP6-P10 JP11 TM1 VSEL TM2 NOC LBAT PROG# LCOM Fast charge timer setting 1 Voltage termination select Fast charge timer setting 2 Selects number of cells Gas gauge power supply Gas gauge programming LED enable
Table1. Lookup Table for D11 Selection
+VDC Input (Volts) Below 15 1518 1821 2124 2427 2730 3032 3235 Motorola Part No. Shorted 1N749 1N755 1N758 1N964A 1N966A 1N967A 1N968A Nominal Zener Voltage 0 4.3 7.5 10 13 16 18 20
EV2014x Fixed Configuration
The EV2014x board has the following fixed characteristics: VCC (4.755.25V) for the bq2004 is regulated onboard from the supply at connector J2 DC. LEDs 1 and 2 indicate charge status. LED3 can replace LED1 and LED2 and provide an optional tri-color LED feature. LEDs D4 through D8 indicate battery capacity in 20% increments.
Jumper-Selectable Configuration
The EV2014x must be configured as described below. TM1 and TM2 (JP3) : Select fast charge safety time/hold-off (see bq2004 data sheet, page 7). Number of Cells (JP4, JP12) : Two resistor-divider networks are provided to select 4 to 10 cells.
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EV2014x
Identifier K1 (blank) F1 O1 S1 Thermistor Keystone RL0703-5744-103-S1 Philips 2322-640-63103 Fenwal Type 16, 197-103LA6-A01 Ozhumi 150-108-00(4) Semetic 103AT-2
EV2014x Setup
1. Configure VSEL, TM1, TM2, and NOC jumpers. Jumper Setting [12]3 1[23] 123 2. Pin State High Low Float
Temperature Disable: Connecting a 10K resistor between THERM and SNS disables temperature control. VSEL (JP2): Selects -V or peak-voltage detection, or disables voltage-based termination (see bq2004 data sheet, page 7). Jumper Setting [12]3 1[23] 123 Pin State High Low Float
Program the bq2014 with jumpers JP6JP10. Jumper Setting 12 [12] LEDs Disabled Enabled
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Enable/disable the voltage regulator with JP5, JP13. Connect the provided thermistor between THERM and PACK-. A 10K resistor across THERM and PACK- disables temperature termination. Connect the RS232 cable from the EV2014x board to the serial port of a standard PC. Please ensure that no memory resident programs use this port.. Connect the load across BAT+ and PACK-. A sense resistor RSNS2 is in series with the negative terminal of the battery. The EV2014x board is supplied with a 0.100ohm, 1% 3W resistor. Please ensure that the discharge load does not exceed the Vsr specification for the bq2014. RSNS2 may be changed to a different resistor value.. Connect the battery to BAT+ and BAT-. Important: Connect the battery ONLY after setting JP6JP10 and JP5, JP13. Attach the power supply to the DCIN and DC RTN connections in J2.
bq2014 VCC Supply (JP5, JP13). These jumpers are used to enable the onboard voltage regulator to the bq2014 from the battery pack. If the battery pack consists of 3 or 4 series cells the gas gauge can be powered directly from the battery with no regulation. For a greater number of cells, the regulator should be enabled. Closed Jumper on JP4, JP12 RB25, R13 RB24, R26 RB23, R25 RB22, R24 RB21, R23 RB20, R22
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Number of Cells User-selectable 10 8 6 5 4 7.
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Programming Pins (JP6JP10). These jumpers are used to configure the gas gauge for battery capacity and self discharge rate. See the bq2014 data sheet for proper configuration. The board is shipped with all pins in the high impedance state. LED Enable (JP11). JP11 enables the gas gauge LEDs. The board is shipped with the LEDs enabled. Jumper Setting JP5, JP13 1 [ 2 3 ], [1 2] 3 [1 2] 3, 1 [ 2 3 ]
Installing the User Interface Program
The User Interface Program (named "EV2014x") runs on any PC-compatible computer. The program may be run from the disk provided, or it may be installed on any directory on the computer's hard disk. To run the program from the hard disk, simply copy all the files from the disk supplied to the hard disk. All the files should reside in the same directory. The User Interface Program installs a driver to control the DQ/RS-232 interface. This driver asks which COM port is connected to the EV2014x Evaluation board. If communication is not established with the EV2014x board, the Main Menu does not appear. Please refer to
Regulator Enabled Disabled
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EV2014x Recommended DC Operating Conditions
Symbol IDC VDC VBAT VTHERM ILOAD Note: Description Maximum input current Maximum input voltage BAT input voltage THERM input voltage Load current Minimum 2.0 + VBAT or 15 0 Typical Maximum 2.4 18 + VBAT or 35 24 5 3 Unit A V V V A Note 1 Notes
1. The VDC+ limits consider the appropriate Zener diode at D11. The voltage at D11 is applicationspecific and limits the VGS of Q1 to a safe enhancement value during Q1 conduction. See Table 1 for recommended D11 selections per VDC+. ESCAPE key Press the ESCAPE key to escape from any function back to the main menu, or to escape from any parameter value screen back to the menu displaying that parameter. Press the F3 key to display a help file for the selected function or parameter.
Appendix B (Troubleshooting) if the program does not establish communication with the EV2014x. The EV2014x uses the PC-AT real-time clock to provide the proper bit timing for serial communication with the bq2014. The modem control lines are used as the singlewire serial interface to the bq2014. Any TSR that uses the PC real-time clock affects the operation of the EV2014x. For proper operation, the EV2014x should not be operated from a DOS shell program. If the PC is a notebook or portable type, it may be configured to save battery power by adjusting the clocks according to the activity under way. Configure the notebook to run in "High Performance" mode for reliable communication between the EV2014x and the PC. The EV2014x UIP terminates if communication with the EV2014x board is lost. Start the User Interface Program as follows: C>EV2014x
F3 key
Main Menu
The Main Menu appears after the EV2014x program has started. If this menu does not appear, communication with the EV2014x has not been established; please refer to Appendix B (Troubleshooting) if the EV2014x does not display the Main Menu. The Main Menu shows six functions that may be activated; see Figure 1. Use the cursor keys (arrow keys) to position the highlighted cursor over the function to be activated and press the ENTER key. For help, press the F3 key, and a help note about the function appears. Press the ESCAPE key to exit from the EV2014x program. The Main Menu functions are as follows: Sends a reset command to the bq2014 Activates a screen from which the bq2014 activity is monitored on a real-time basis. Activates a screen from which the Digital Magnitude Filter can be changed. The default filter value is -0.3mV, +0.38mV. The bq2014 data sheet (Dec. 1994 B or later) defines valid options for this filter. Allows entering a file name to which bq2014 data will be logged, and the logging period in seconds. When the log is
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Using the EV2014x Program
EV2014x is a menu-driven program. Almost all of the functions and entries are made by positioning the highlighted cursor on the function desired and pressing the ENTER key, or by typing a value and then pressing the ENTER key. Key functions are as follows: ARROW keys ENTER key U s e t h e a r r o w k e y s t o m o v e t h e h i g hlighted cursor around the screen. Press the ENTER key to select the value currently being displayed for a parameter, or to perform a function selected by the highlighted cursor.
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EV2014x
activated, t h e d i s p l a y c h a n g e s t o t h e Monitor screen with a top display of: Logging Record: xx Activates a screen showing the current program settings for the bq2014. This allows the user to determine the apparent offset voltage of the bq2014 under test. A minimum of 6 minutes are required to complete the VOS measurement, which has a resolution of ±0.15mV per 6 minutes. Sense Resistor Value times 256 and divided by the sense resistor to give mAh. This is the sense resistor value from the Programming menu.
Average VSR This is the average battery current. Current Time Remaining During discharge only, this is the time remaining at the average current (NAC / Avg. VSR current)
Digital This is the value of the digital magnitude Filter Setting filter. Temp Step This is a display of the active temperature step, which ranges from 0 (for temperatures 80°C). This indicates the charging/discharging activity occurring with the battery. CHARGE is displayed if the battery is c h a r g i n g , w h i l e D I S C H A R G I N G i s d i splayed if the battery is being discharged, or if it is idle (no charging taking place). OVERLOAD is displayed if the voltage drop across the sense resistor exceeds the VSR1 threshold. Please note that the appearance of CHARGE or DISCHARGE indicators is rate-dependent, and may take some time after the application of a charging current or a discharge load depending on the PFC and scale selected, and the rate of charge or discharge being applied.
Monitor Screen
This screen monitors real-time changes of the bq2014; see Figure 2. The program continually updates the monitor screen. As conditions change, the new values are displayed. Time Empty/Full Time of day in HH:MM:DD, 24-hour notation. This indicates the current value for GG in the TMPGG register of the bq2014. The capacity value is given in 1 16th steps. Current date in MM/DD/YY notation. NAC register values multiplied by the scale value and divided by the sense resistor value to give mAh. Last Measured Discharge expressed in terms of mAH. This is the 8-bit LMD register value multiplied by the scale value Activity
Date NAC
LMD
Benchmarq bq2014 Evaluation Board Main Menu (v2.3)
Please enter the SR, # of cells in Display Program for Proper Operation
ESC to exit program
F3 for Help
Figure 1. Main Menu
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