ZHCSHW3D March   2018  – November 2019 INA190

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
    1.     Device Images
      1.      典型应用
  4. 4 修订历史记录
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Precision Current Measurement
      2. 7.3.2 Low Input Bias Current
      3. 7.3.3 Low Quiescent Current With Output Enable
      4. 7.3.4 Bidirectional Current Monitoring
      5. 7.3.5 High-Side and Low-Side Current Sensing
      6. 7.3.6 High Common-Mode Rejection
      7. 7.3.7 Rail-to-Rail Output Swing
    4. 7.4 Device Functional Modes
      1. 7.4.1 Normal Operation
      2. 7.4.2 Unidirectional Mode
      3. 7.4.3 Bidirectional Mode
      4. 7.4.4 Input Differential Overload
      5. 7.4.5 Shutdown
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Basic Connections
      2. 8.1.2 RSENSE and Device Gain Selection
      3. 8.1.3 Signal Conditioning
      4. 8.1.4 Common-Mode Voltage Transients
    2. 8.2 Typical Applications
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curve
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Examples
  11. 11器件和文档支持
    1. 11.1 文档支持
      1. 11.1.1 相关文档
    2. 11.2 接收文档更新通知
    3. 11.3 支持资源
    4. 11.4 商标
    5. 11.5 静电放电警告
    6. 11.6 Glossary
  12. 12机械、封装和可订购信息

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息

8.1.2 RSENSE and Device Gain Selection

The accuracy of any current-sense amplifier is maximized by choosing the current-sense resistor to be as large as possible. A large sense resistor maximizes the differential input signal for a given amount of current flow and reduces the error contribution of the offset voltage. However, there are practical limits as to how large the current-sense resistor can be in a given application because of the resistor size and maximum allowable power dissipation. Equation 2 gives the maximum value for the current-sense resistor for a given power dissipation budget:

Equation 2. INA190 Rsense_PDmax_bos793.gif

where

  • PDMAX is the maximum allowable power dissipation in RSENSE.
  • IMAX is the maximum current that will flow through RSENSE.

An additional limitation on the size of the current-sense resistor and device gain is due to the power-supply voltage, VS, and device swing-to-rail limitations. In order to make sure that the current-sense signal is properly passed to the output, both positive and negative output swing limitations must be examined. Equation 3 provides the maximum values of RSENSE and GAIN to keep the device from exceeding the positive swing limitation.

Equation 3. INA190 Rsense_SP_bos793.gif

where

  • IMAX is the maximum current that will flow through RSENSE.
  • GAIN is the gain of the current-sense amplifier.
  • VSP is the positive output swing as specified in the data sheet.
  • VREF is the externally applied voltage on the REF pin.

To avoid positive output swing limitations when selecting the value of RSENSE, there is always a trade-off between the value of the sense resistor and the gain of the device under consideration. If the sense resistor selected for the maximum power dissipation is too large, then it is possible to select a lower-gain device in order to avoid positive swing limitations.

The negative swing limitation places a limit on how small the sense resistor value can be for a given application. Equation 4 provides the limit on the minimum value of the sense resistor.

Equation 4. INA190 Rsense_SN_bos793.gif

where

  • IMIN is the minimum current that will flow through RSENSE.
  • GAIN is the gain of the current-sense amplifier.
  • VSN is the negative output swing of the device (see Rail-to-Rail Output Swing).
  • VREF is the externally applied voltage on the REF pin.

In addition to adjusting RSENSE and the device gain, the voltage applied to the REF pin can be slightly increased above GND to avoid negative swing limitations.