JAJSIZ8B July   2015  – September 2024 INA226-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 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Basic ADC Functions
        1. 6.3.1.1 Power Calculation
        2. 6.3.1.2 Alert Pin
    4. 6.4 Device Functional Modes
      1. 6.4.1 Averaging and Conversion Time Considerations
      2. 6.4.2 Filtering and Input Considerations
    5. 6.5 Programming
      1. 6.5.1 Programming the Calibration Register
      2. 6.5.2 Programming the Power Measurement Engine
        1. 6.5.2.1 Calibration Register and Scaling
      3. 6.5.3 Simple Current Shunt Monitor Usage (No Programming Necessary)
      4. 6.5.4 Default Settings
      5. 6.5.5 Bus Overview
        1. 6.5.5.1 Serial Bus Address
        2. 6.5.5.2 Serial Interface
        3. 6.5.5.3 Writing to and Reading From the INA226-Q1
          1. 6.5.5.3.1 High-Speed I2C Mode
        4. 6.5.5.4 SMBus Alert Response
  8. 7 Registers
    1. 7.1 Register Maps
      1. 7.1.1  Configuration Register (00h) (Read/Write)
      2. 7.1.2  Shunt Voltage Register (01h) (Read-Only)
      3. 7.1.3  Bus Voltage Register (02h) (Read-Only) #GUID-792F23A7-1E45-4FB9-9334-0BF769622DE4/SBOS5477597
      4. 7.1.4  Power Register (03h) (Read-Only)
      5. 7.1.5  Current Register (04h) (Read-Only)
      6. 7.1.6  Calibration Register (05h) (Read/Write)
      7. 7.1.7  Mask/Enable Register (06h) (Read/Write)
      8. 7.1.8  Alert Limit Register (07h) (Read/Write)
      9. 7.1.9  Manufacturer ID Register (FEh) (Read-Only)
      10. 7.1.10 Die ID Register (FFh) (Read-Only)
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 High-Side Sensing Circuit Application
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Development Support
    2. 9.2 ドキュメントの更新通知を受け取る方法
    3. 9.3 サポート・リソース
    4. 9.4 Trademarks
    5. 9.5 静電気放電に関する注意事項
    6. 9.6 用語集
  11. 10Revision History
  12. 11Mechanical, 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

6.5 Programming

An important aspect of the INA226-Q1 is that the device does not necessarily measure current or power. The device measures both the differential voltage applied between the IN+ and IN- input pins and the voltage applied to the VBUS pin. For the device to report both current and power values, the user must program the resolution of the Current Register (04h) and the value of the shunt resistor present in the application to develop the differential voltage applied between the input pins. The Power Register (03h) is internally set to be 25 times the programmed Current_LSB. Both the Current_LSB and shunt resistor value are used in the calculation of the Calibration Register value the device uses to calculate the corresponding current and power values based on the measured shunt and bus voltages.

The Calibration Register is calculated based on Equation 1. This equation includes the term Current_LSB, which is the programmed value for the LSB for the Current Register (04h). The user uses this value to convert the value in the Current Register (04h) to the actual current in amperes. The highest resolution for the Current Register (04h) can be obtained by using the smallest allowable Current_LSB based on the maximum expected current as shown in Equation 2. While this value yields the highest resolution, selecting a value for the Current_LSB to the nearest round number above this value is common to simplify the conversion of the Current Register (04h) and Power Register (03h) to amperes and watts respectively. The RSHUNT term is the value of the external shunt used to develop the differential voltage across the input pins. 

Equation 1. C A L = 0.00512 C u r r e n t _ L S B × R S H U N T

where

  • 0.00512 is an internal fixed value used to verify scaling is maintained properly
Equation 2. C u r r e n t _ L S B = M a x i m u m   E x p e c t e d   C u r r e n t 2 15

After programming the Calibration Register, the Current Register (04h) and Power Register (03h) update accordingly based on the corresponding shunt voltage and bus voltage measurements. Until the Calibration Register is programmed, the Current Register (04h) and Power Register (03h) remain at zero.