ZHCSC46C February   2014  – June 2021 INA300

PRODUCTION DATA  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings (1)
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 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 Selecting a Current-Sensing Resistor
        1. 7.3.1.1 Selecting a Current-Sensing Resistor: Example
      2. 7.3.2 Setting The Current-Limit Threshold
        1. 7.3.2.1 Resistor-Controlled Current Limit
        2. 7.3.2.2 Voltage Source-Controlled Current Limit
      3. 7.3.3 Delay Setting
      4. 7.3.4 Alert Timing Response
      5. 7.3.5 Selectable Hysteresis
      6. 7.3.6 Alert Output
      7. 7.3.7 Noise Adjustment Factor (NAF)
    4. 7.4 Device Functional Modes
      1. 7.4.1 Alert Mode
        1. 7.4.1.1 Transparent Output Mode
        2. 7.4.1.2 Latch Output Mode
      2. 7.4.2 Disable Mode
      3. 7.4.3 Input Filtering
      4. 7.4.4 Using the INA300 INA300 With Common-Mode Transients Above 36 V
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Unidirectional Operation
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curve
      2. 8.2.2 Bidirectional Operation
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curve
      3. 8.2.3 Window Comparator
        1. 8.2.3.1 Design Requirements
        2. 8.2.3.2 Detailed Design Procedure
        3. 8.2.3.3 Application Curve
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 接收文档更新通知
    3. 11.3 支持资源
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 术语表
  12. 12Mechanical, Packaging, and Orderable Information

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7.3.1.1 Selecting a Current-Sensing Resistor: Example

In this example, the trade-offs involved in selecting a current-sensing resistor are discussed. This example requires a 5% measurement accuracy for detecting a 10-A overcurrent event at a 50-µs delay setting where only 250 mW is allowable for the dissipation across the current-sensing resistor at the full-scale current level. Although the maximum power dissipation is defined as 250 mW, a lower dissipation is preferred to improve system efficiency. Some initial assumptions are made that are used in this example: the limit setting resistor, RLIMIT, is a 1% component and the maximum tolerance specification for the internal threshold setting current source, 0.5%, is used. Given the total error budget of 5%, up to 3.5% of error is available to be attributed to the internal offset of the device.

As shown in Table 7-1, the maximum value calculated for the current-sensing resistor with these requirements is 2.5 mΩ. Although this value satisfies the maximum power dissipation requirement of 250 mW, headroom is available from the 5% maximum total error to reduce the value of the current-sensing resistor and reduce the power dissipation further. Selecting a 1.5-mΩ, current-sensing resistor value offers a tradeoff for reducing the power dissipation in this scenario by approximately 40%, while still remaining within the defined accuracy region.

Table 7-1 Calculating the Current-Sensing Resistor, RSENSE
PARAMETER EQUATION VALUE UNIT
Maximum measurement error 5%
IMAX Maximum current 10 A
PRSENSE Maximum allowable RSENSE power dissipation RSENSE × IMAX2 250 mW
Initial error RLIMIT + ILIMIT tolerances 1.5%
RSENSE_MAX Maximum sensing resistor value PRSENSE / IMAX2 2.5 mΩ
VSENSE_MAX Input sense voltage RSENSE_MAX × IMAX 25 mV
VOS Error Offset voltage error (VOS / VSENSE_MAX) × 100 2%
Error_Available Maximum allowable offset error Maximum Error – Initial Error 3.5%
VSENSE_MIN Minimum input sense voltage VOS / (Error_Available / 100) 14.3 mV
RSENSE_MIN Minimum sensing resistor value VSENSE_MIN / IMAX 1.43 mΩ
PRSENSE_MIN Minimum power dissipation RSENSE_MIN × IMAX2 143 mW