JAJSN53A February   2012  – December 2021 INA230

PRODUCTION DATA  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
  4. 4 Revision History
  5. 5 Related Products
  6. 6 Pin Configuration and Functions
  7. 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 (I2C)
    7. 7.7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Basic ADC Functions
      2. 8.3.2 Power Calculation
      3. 8.3.3 Alert Pin
    4. 8.4 Device Functional Modes
      1. 8.4.1 Averaging and Conversion Time Considerations
      2. 8.4.2 Filtering and Input Considerations
    5. 8.5 Programming
      1. 8.5.1 Programming the Calibration Register
      2. 8.5.2 Programming the INA230 Power Measurement Engine
        1. 8.5.2.1 Calibration Register and Scaling
      3. 8.5.3 Simple Current Shunt Monitor Usage (No Programming Necessary)
      4. 8.5.4 Default INA230 Settings
      5. 8.5.5 Bus Overview
        1. 8.5.5.1 Serial Bus Address
        2. 8.5.5.2 Serial Interface
      6. 8.5.6 Writing to and Reading From the I2C Serial Interface
        1. 8.5.6.1 High-Speed I2C Mode
      7. 8.5.7 SMBus Alert Response
    6. 8.6 Register Maps
      1. 8.6.1 Configuration Register (00h, Read/Write)
      2. 8.6.2 AVG Bit Settings [11:9]
      3. 8.6.3 VBUS CT Bit Settings [8:6]
      4. 8.6.4 VSH CT Bit Settings [5:3]
      5. 8.6.5 Mode Settings [2:0]
      6. 8.6.6 Data Output Register
        1. 8.6.6.1 Shunt Voltage Register (01h, Read-Only)
        2. 8.6.6.2 Bus Voltage Register (02h, Read-Only) (1)
        3. 8.6.6.3 Power Register (03h, Read-Only)
        4. 8.6.6.4 Current Register (04h, Read-Only)
        5. 8.6.6.5 Calibration Register (05h, Read/Write)
        6. 8.6.6.6 Mask/Enable Register (06h, Read/Write)
        7. 8.6.6.7 Alert Limit Register (07h, Read/Write)
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 High-Side Sensing Circuit Application
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 サポート・リソース
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, 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

8.4.1 Averaging and Conversion Time Considerations

The INA230 device offers programmable conversion times (tCT) for both the shunt voltage and bus voltage measurements. The conversion times for these measurements can be selected from as fast as 140 μs to as long as 8.244 ms. The conversion time settings, along with the programmable averaging mode, allow the device to be configured to optimize the available timing requirements in a given application. For example, if a system requires that data be read every 5 ms, the device could be configured with the conversion times set to 588 μs for both shunt and bus voltage measurements and the averaging mode set to 4. This configuration results in the data updating approximately every 4.7 ms. The device could also be configured with a different conversion time setting for the shunt and bus voltage measurements. This type of approach is common in applications where the bus voltage tends to be relatively stable. This situation can allow for the time focused on the bus voltage measurement to be reduced relative to the shunt voltage measurement. The shunt voltage conversion time could be set to 4.156 ms with the bus voltage conversion time set to 588 μs, with the averaging mode set to 1. This configuration also results in data updating approximately every 4.7 ms.

There are trade-offs associated with the settings for conversion time and the averaging mode used. The averaging feature can significantly improve the measurement accuracy by effectively filtering the signal. This approach allows the device to reduce any noise in the measurement that may be caused by noise coupling into the signal. A greater number of averages enables the device to be more effective in reducing the noise component of the measurement.

The conversion times selected can also have an impact on the measurement accuracy. Figure 8-2 shows multiple conversion times to illustrate the impact of noise on the measurement. To achieve the highest accuracy measurement possible, use a combination of the longest allowable conversion times and highest number of averages based on the timing requirements of the system.

GUID-B2AA2C85-6AAA-4333-9FEA-5F9C7CEC114C-low.gifFigure 8-2 Noise vs. Conversion Time