JAJSL30 July   2023 ADS131B24-Q1

PRODUCTION DATA  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  5. 4 Revision History
  6. 5 概要 (続き)
  7. 6 Pin Configuration and Functions
  8. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Timing Requirements
    7. 7.7 Switching Characteristics
    8. 7.8 Timing Diagram
    9. 7.9 Typical Characteristics
  9. 8 Parameter Measurement Information
    1. 8.1 Offset Drift Measurement
    2. 8.2 Gain Drift Measurement
    3. 8.3 Noise Performance
  10. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Naming Conventions
      2. 9.3.2 Precision Voltage References (REFA, REFB)
      3. 9.3.3 Clocking (MCLK, OSCM, OSCD)
      4. 9.3.4 ADC1y
        1. 9.3.4.1 ADC1y Input Multiplexer
        2. 9.3.4.2 ADC1y Programmable Gain Amplifier (PGA)
        3. 9.3.4.3 ADC1y ΔΣ Modulator
        4. 9.3.4.4 ADC1y Digital Filter
        5. 9.3.4.5 ADC1y Offset and Gain Calibration
        6. 9.3.4.6 ADC1y Conversion Data
      5. 9.3.5 ADC2y
        1. 9.3.5.1 ADC2y Input Multiplexer
        2. 9.3.5.2 ADC2y Programmable Gain Amplifier (PGA)
        3. 9.3.5.3 ADC2y ΔΣ Modulator
        4. 9.3.5.4 ADC2y Digital Filter
        5. 9.3.5.5 ADC2y Offset and Gain Calibration
        6. 9.3.5.6 ADC2y Sequencer
        7. 9.3.5.7 VCMy Buffers
        8. 9.3.5.8 ADC2y Measurement Configurations
        9. 9.3.5.9 ADC2y Conversion Data
      6. 9.3.6 General-Purpose Digital Inputs and Outputs (GPIO0 to GPIO4)
        1. 9.3.6.1 GPIOx PWM Output Configuration
        2. 9.3.6.2 GPIOx PWM Input Readback
      7. 9.3.7 General-Purpose Digital Inputs and Outputs (GPIO0A, GPIO1A, GPIO0B, GPIO1B)
      8. 9.3.8 Monitors and Diagnostics
        1. 9.3.8.1  Supply Monitors
        2. 9.3.8.2  Clock Monitors
        3. 9.3.8.3  Digital Monitors
          1. 9.3.8.3.1 Register Map CRC
          2. 9.3.8.3.2 Memory Map CRC
          3. 9.3.8.3.3 GPIO Readback
        4. 9.3.8.4  Communication Monitors
        5. 9.3.8.5  Fault Flags and Fault Masking
        6. 9.3.8.6  FAULT Pin
        7. 9.3.8.7  Diagnostics and Diagnostic Procedure
        8. 9.3.8.8  Indicators
        9. 9.3.8.9  Conversion and Sequence Counters
        10. 9.3.8.10 Supply Voltage Readback
        11. 9.3.8.11 Temperature Sensors (TSA, TSB)
        12. 9.3.8.12 Test DACs (TDACA, TDACB)
        13. 9.3.8.13 Open-Wire Detection
        14. 9.3.8.14 Missing Host Detection and MHD Pin
        15. 9.3.8.15 Overcurrent Comparators (OCCA, OCCB)
          1. 9.3.8.15.1 OCCA and OCCB Pins
          2. 9.3.8.15.2 Overcurrent Indication Response Time
    4. 9.4 デバイスの機能モード
      1. 9.4.1 Power-Up and Reset
        1. 9.4.1.1 Power-On Reset (POR)
        2. 9.4.1.2 RESETn Pin
        3. 9.4.1.3 RESET Command
      2. 9.4.2 Operating Modes
        1. 9.4.2.1 Active Mode
        2. 9.4.2.2 Standby Mode
        3. 9.4.2.3 Power-Down Mode
      3. 9.4.3 ADC Conversion Modes
        1. 9.4.3.1 ADC1y Conversion Modes
          1. 9.4.3.1.1 Continuous-Conversion Mode
          2. 9.4.3.1.2 Single-Shot Conversion Mode
          3. 9.4.3.1.3 Global-Chop Mode
            1. 9.4.3.1.3.1 Overcurrent Indication Response Time in Global-Chop Mode
        2. 9.4.3.2 ADC2y Sequencer Operation and Sequence Modes
          1. 9.4.3.2.1 Continuous Sequence Mode
          2. 9.4.3.2.2 Single-Shot Sequence Mode
          3. 9.4.3.2.3 Synchronized Single-Shot Sequence Mode Based on ADC1y Conversion Starts
    5. 9.5 Programming
      1. 9.5.1 Serial Interface
        1. 9.5.1.1 Serial Interface Signals
          1. 9.5.1.1.1 Chip Select (CSn)
          2. 9.5.1.1.2 Serial Data Clock (SCLK)
          3. 9.5.1.1.3 Serial Data Input (SDI)
          4. 9.5.1.1.4 Serial Data Output (SDO)
          5. 9.5.1.1.5 Data Ready (DRDYn)
        2. 9.5.1.2 Serial Interface Communication Structure
          1. 9.5.1.2.1 SPI Communication Frames
          2. 9.5.1.2.2 SPI Communication Words
          3. 9.5.1.2.3 STATUS Word
          4. 9.5.1.2.4 Communication Cyclic Redundancy Check (CRC)
          5. 9.5.1.2.5 Commands
            1. 9.5.1.2.5.1 NULL (0000 0000 0000 0000b)
            2. 9.5.1.2.5.2 RESET (0000 0000 0001 0001b)
            3. 9.5.1.2.5.3 LOCK (0000 0101 0101 0101b)
            4. 9.5.1.2.5.4 UNLOCK (0000 0110 0101 0101b)
            5. 9.5.1.2.5.5 WREG (011a aaaa aaa0 0nnnb)
            6. 9.5.1.2.5.6 RREG (101a aaaa aaan nnnnb)
          6. 9.5.1.2.6 SCLK Counter
          7. 9.5.1.2.7 SPI Timeout
          8. 9.5.1.2.8 Reading ADC1A, ADC1B, ADC2A, and ADC2B Conversion Data
          9. 9.5.1.2.9 DRDYn Pin Behavior
    6. 9.6 Register Map
      1. 9.6.1 Registers
  11. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Unused Inputs and Outputs
      2. 10.1.2 Minimum Interface Connections
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Current Shunt Measurement
        2. 10.2.2.2 Battery Pack Voltage Measurement
        3. 10.2.2.3 Shunt Temperature Measurement
        4. 10.2.2.4 Analog Output Temperature Sensor Measurement
      3. 10.2.3 Application Curves
    3. 10.3 Power Supply Recommendations
      1. 10.3.1 Power-Supply Options
        1. 10.3.1.1 Single Unregulated External 4-V to 16-V Supply (3.3-V Digital I/O Levels)
        2. 10.3.1.2 Single Regulated External 3.3-V Supply (3.3-V Digital IO Levels)
        3. 10.3.1.3 Single Regulated External 5-V Supply (5-V Digital I/O Levels)
      2. 10.3.2 Power-Supply Sequencing
      3. 10.3.3 Power-Supply Decoupling
    4. 10.4 Layout
      1. 10.4.1 Layout Guidelines
      2. 10.4.2 Layout Example
  12. 11デバイスおよびドキュメントのサポート
    1. 11.1 ドキュメントのサポート
      1. 11.1.1 関連資料
    2. 11.2 ドキュメントの更新通知を受け取る方法
    3. 11.3 サポート・リソース
    4. 11.4 商標
    5. 11.5 静電気放電に関する注意事項
    6. 11.6 用語集
  13. 12Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

10.2.2.1 Current Shunt Measurement

In a typical BMS application, the current through the shunt resistor must be measured in both directions for charging and discharging the battery pack. In an overcurrent or short-circuit condition, the current can be as high as IBAT_MAX = ±3 kA in this example application. Therefore, the maximum voltage drop across the shunt is up to VSHUNT = RSHUNT × IBAT_MAX = 50 μΩ × ±3 kA = ±150 mV.

To measure this shunt voltage, ADC1A is configured for gain = 8, which allows differential voltage measurements of VIN1A = VCPA – VCNA = ±VREFA / 8 = ±1.25 V / 8 = ±156 mV. The integrated charge pump in the device allows voltage measurements 312.5 mV below AGNDA while using a unipolar analog power supply. This bipolar voltage measurement capability is important because one side of the shunt is connected to the same GND potential as the AGNDA pin of the ADS131B24-Q1, which means that the absolute voltage that the device must measure is up to 150 mV below AGNDA.

To enable fast overcurrent detection within 1 ms while providing high accuracy and resolution, the ADS131B24-Q1 is configured to operate at 4 kSPS (OSR = 1024)) using global-chop mode. Global-chop mode enables measurements with minimal offset error over temperature and time. The conversion time using these settings is 0.75 ms according to Equation 21. The input-referred noise is approximately 1.28 μVRMS / √2 = 0.91 μVRMS following the explanations in the Global-Chop Mode section. Thus, currents as small as 0.91 μVRMS / 50 μΩ = 18 mA can be resolved. The resolution can be further improved by averaging the conversion results over a longer period of time in the microcontroller that interfaces with the ADS131B24-Q1.

The –3-dB corner frequency of the differential antialiasing filter on the analog inputs (R13, R14, and C6) is set to 1 / (2 × ᴨ × 2 × 100 Ω × 47 nF) = 16.9 kHz to provide more then 40-dB attenuation at the ADC1A modulator frequency. Keep the series resistor values (R13 and R14) small to avoid additional offset errors created by the voltage drop across the resistors because of the ADC1A input currents.

ADC1B is configured identical to ADC1A to allow for simultaneous sampling of the shunt voltage with the same digital filter response.