DS2781E+ Maxim Integrated Products, DS2781E+ Datasheet

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... PIO VIN OVD VB SNS VSS P- Protection Circuit ORDERING INFORMATION PART DS2781E+ DS2781E+T&R DS2781G+ DS2781G+T&R +Denotes a lead-free/RoHS-compliant package. T&R = Tape and reel. *EP = Exposed pad. 1-Wire is a registered trademark of Maxim Integrated Products, Inc. 1-Cell or 2-Cell Stand-Alone PIN CONFIGURATIONS TOP VIEW capacity for VSS ...

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ABSOLUTE MAXIMUM RATINGS Voltage Range Relative Voltage Range on Any Pin Relative to V Continuous Sink Current, DQ, PIO Operating Temperature Range Storage Temperature Range Soldering Temperature Stresses beyond those listed under ...

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PARAMETER Voltage Full-Scale Voltage Error Current Resolution Current Full-Scale Current Gain Error Current Offset Error Accumulated Current Offset Timebase Error ELECTRICAL CHARACTERISTICS: 1-WIRE INTERFACE, STANDARD (V = 2.5V to 10V -20°C to +70°C PARAMETER Time Slot ...

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EEPROM RELIABILITY SPECIFICATION (V = 2.5V to 10V -20°C to +70°C, unless otherwise noted. Typical values are PARAMETER EEPROM Copy Time EEPROM Copy Endurance Note 1: All voltages are referenced to V Note 2: ...

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Figure 1. Block Diagram VDD V POR PIO DQ OVD EEPROM SNS DETAILED DESCRIPTION The DS2781 operates directly from 2.5V to 10V and supports single or dual cell Lithium-ion battery packs. Nonvolatile storage is provided for cell compensation and application ...

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Figure 2. Typical Operating Circuit PACK+ 150 DATA 5.6V PACK- Protection Circuit POWER MODES The DS2781 has two power modes: ACTIVE and SLEEP. On initial power up, the DS2781 defaults to ACTIVE mode. While in ACTIVE mode, the DS2781 is ...

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VOLTAGE MEASUREMENT Battery voltage is measured at the V 9.76mV. The result is updated every 440ms and placed in the VOLTAGE register in two’s complement form. Voltages above the maximum register value are reported at the maximum value; voltages below ...

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Figure 5. Current Register Format CURRENT MSB—Address 0Eh MSb “S”: sign bit( SNS 1.5625μV CURRENT OFFSET CORRECTION Every 1024th conversion, the ADC measures its input offset to facilitate offset ...

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CURRENT MEASUREMENT CALIBRATION The DS2781’s current measurement gain can be adjusted through the RSGAIN register, which is factory-calibrated to meet the data sheet specified accuracy. RSGAIN is user accessible and can be reprogrammed after module or pack manufacture to improve ...

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Current measurement and accumulation begins with the second conversion following a write to the ACR. Writing ACR clears the fractional values in ACRL. The Format of the ACR register is shown in Figure 8, ...

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ACCUMULATION BIAS The Accumulation Bias register (AB) allows an arbitrary bias to be introduced into the current-accumulation process. The AB can be used to account for currents that do not flow through the sense resistor, estimate currents too small to ...

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Figure 11. Top-Level Algorithm Diagram Voltage (R) Temperature (R) Current (R) Accumulated Current (ACR) (R/W) Average Current (R) Cell Parameters 16 bytes (EEPROM) Aging Cap (AC) (2 bytes EE) Age Scalar (AS) (1 bytes EE) Sense Resistor’ (RSNSP) (1byte EE) ...

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... LSB of the slope registers equals 61ppm so the Full Segment 3 Slope register (location 0x6Dh) would be programmed with a value of 0x13h. Each slope register has a dynamic range 0ppm to 15555ppm. FuelPack is a trademark of Maxim Integrated Products, Inc. Seg. 2 Seg. 3 ...

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Active Empty: The Active Empty curve defines the temperature variation in the empty point of the discharge profile based on a high level load current (one that is sustained during a high power operating mode) and the minimum voltage required ...

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APPLICATION PARAMETERS In addition to cell model characteristics, several application parameters are needed to detect the full and empty points, as well as calculate results in mAh units. Sense Resistor Prime (RSNSP): RSNSP stores the value of the sense resistor ...

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CAPACITY ESTIMATION UTILITY FUNCTIONS Aging Estimation As discussed above, the AS register value is adjusted occasionally based on cumulative discharge. As the ACR register decrements during each discharge cycle, an internal counter is incremented until equal to 32 times AC. ...

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RESULT REGISTERS The DS2781 processes measurement and cell characteristics on a 440ms interval and yields seven result registers. The result registers are sufficient for direct display to the user in most applications. The host system can produce customized values for ...

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Remaining Active Relative Capacity (RARC) [%]: RARC reports the capacity available under the current temperature conditions at the Active Empty discharge rate (IAE) to the Active Empty point in relative units of percent. RARC is 8 bits. See Figure 16. ...

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STATUS REGISTER The STATUS register contains bits that report the device status. The bits can be set internally by the DS2781. The CHGTF, AEF, SEF, LEARNF and VER bits are read only bits that can be cleared by hardware. The ...

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CONTROL REGISTER All CONTROL register bits are read and write accessible. The CONTROL register is recalled from Parameter EEPROM memory at power-up. Register bit values can be modified in shadow RAM after power-up. Shadow RAM values can be saved as ...

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EEPROM REGISTER The EEPROM register provides access control of the EEPROM blocks. EEPROM blocks can be locked to prevent alteration of data within the block. Locking a block disables write access to the block. Once a block is locked, it ...

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PARAMETER EEPROM Model data for the cells, as well as application operating parameters are stored in the Parameter EEPROM memory (block 1, addresses 60h–7Fh). The ACR (MSB and LSB) and AS registers are automatically saved to EEPROM when the RARC ...

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Table 3. Parameter EEPROM Memory Block 1 ADDRESS DESCRIPTION (HEX) 60 CONTROL - Control Register Accumulation Bias Aging Capacity MSB Aging Capacity LSB 64 VCHG - Charge Voltage 65 IMIN - ...

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In the circuit in Figure 23, the shift register bits are initialized to 0. Then, starting with the least significant bit of the family code, one bit at a time is shifted in. After the 8th bit of the family ...

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TRANSACTION SEQUENCE The protocol for accessing the DS2781 through the 1-Wire port is as follows: Initialization Net Address Command Function Command Transaction/Data The sections that follow describe each of these steps in detail. All transactions of the 1-Wire bus begin ...

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FUNCTION COMMANDS After successfully completing one of the net address commands, the bus master can access the features of the DS2781 with any of the function commands described in the following paragraphs. The name of each function is followed by ...

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Table 4. Function Commands COMMAND DESCRIPTION Reads data from Read Data memory starting at address XX Writes data to Write Data memory starting at address XX Copies shadow RAM data to Copy Data EEPROM block containing address XX Recalls EEPROM ...

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Figure 25. Net Address Command Flowchart 33h / 39h NO READ YES DS2781 Tx FAMILY CODE 1 BYTE DS2781 Tx SERIAL NUMBER 6 BYTES DS2781 Tx CRC 1 BYTE CLEAR RESUME MASTER TX FUNCTION COMMAND SET YES RESUME FLAG MASTER ...

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SIGNALING The 1-Wire bus requires strict signaling protocols to ensure data integrity. The four protocols used by the DS2781 are as follows: the initialization sequence (reset pulse followed by presence pulse), write 0, write 1, and read data. All ...

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Figure 27. 1-Wire Write- and Read-Time Slots WRITE 0 SLOT V PULLUP GND DS2781 Sample Window Mode MIN Standard 15μs 15μs Overdrive 2μs 1μs READ 0 SLOT V PULLUP GND Master Sample Window t RDV LINE TYPE LEGEND: Bus master ...

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... Maxim/Dallas Semiconductor cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim/Dallas Semiconductor product. No circuit patent licenses are implied. Maxim/Dallas Semiconductor reserves the right to change the circuitry and specifications without notice at any time The Maxim logo is a registered trademark of Maxim Integrated Products, Inc. The Dallas logo is a registered trademark of Dallas Semiconductor Corporation. DESCRIPTION © ...