JAJS491K July   2008  – March 2021 DRV8800 , DRV8801

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 Pin Configuration and 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 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagrams
    3. 8.3 Feature Description
      1. 8.3.1  Logic Inputs
      2. 8.3.2  VREG (DRV8800 Only)
      3. 8.3.3  VPROPI (DRV8801 Only)
        1. 8.3.3.1 Connecting VPROPI Output to ADC
      4. 8.3.4  Charge Pump
      5. 8.3.5  Shutdown
      6. 8.3.6  Low-Power Mode
      7. 8.3.7  Braking
      8. 8.3.8  Diagnostic Output
      9. 8.3.9  Thermal Shutdown (TSD)
      10. 8.3.10 Overcurrent Protection
      11. 8.3.11 SENSE
    4. 8.4 Device Functional Modes
      1. 8.4.1 Device Operation
        1. 8.4.1.1 Slow-Decay SR (Brake Mode)
        2. 8.4.1.2 Fast Decay With Synchronous Rectification
          1. 8.4.1.2.1 34
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Motor Voltage
        2. 9.2.2.2 Power Dissipation
        3. 9.2.2.3 Thermal Considerations
          1. 9.2.2.3.1 Junction-to-Ambiant Thermal Impedance (ƟJA)
        4. 9.2.2.4 Motor Current Trip Point
        5. 9.2.2.5 Sense Resistor Selection
        6. 9.2.2.6 Drive Current
      3. 9.2.3 Pulse-Width Modulating
        1. 9.2.3.1 Pulse-Width Modulating ENABLE
        2. 9.2.3.2 Pulse-Width Modulating PHASE
      4. 9.2.4 Application Curves
    3. 9.3 Parallel Configuration
      1. 9.3.1 Parallel Connections
      2. 9.3.2 Non – Parallel Connections
      3. 9.3.3 Wiring nFAULT as Wired OR
      4. 9.3.4 Electrical Considerations
        1. 9.3.4.1 Device Spacing
        2. 9.3.4.2 Recirculation Current Handling
        3. 9.3.4.3 Sense Resistor Selection
        4. 9.3.4.4 Maximum System Current
  10. 10Power Supply Recommendations
    1. 10.1 Bulk Capacitance
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Related Links
    2. 12.2 Trademarks
    3. 12.3 静電気放電に関する注意事項
    4. 12.4 用語集
  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

8.3.11 SENSE

A low-value SENSE resistor is used to set an overcurrent threshold lower than the default maximum value of 2.8 A and to provide a voltage for VPROPI (DRV8801 Only). This SENSE resistor must be connected between the SENSE pin and ground. To minimize ground-trace IR drops in sensing the output current level, the current-sensing resistor should have an independent ground return to the star ground point. This trace should be as short as possible. For low-value sense resistors, the IR drops in the PCB can be significant, and should be taken into account.

A direct connection to ground yields a SENSE voltage equal to zero. In that case, maximum current is 2.8 A and VPROPI outputs 0 V. A resistor connected as explained before, will yield a VPROPI output as detailed in Section 8.3.3. Size the sense resistor such that voltage drop across the sense resistor is less than 500mV under normal loading conditions. Any voltage equal or larger to 500 mV will signal the device to hi-Z the H-bridge output as overcurrent trip threshold has been reached. In this case, device will enter recirculation as stipulated by the MODE input pin. The device automatically retries with a period of t(OCP).

Equation 2 shows the value of the resistor to a particular current setting.

Equation 2. GUID-20201203-CA0I-PT90-KQTM-278ZGBD1HRF2-low.gif