JAJSLP6F June   2012  – April 2021 DRV8837 , DRV8838

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
    1.     Pin Functions
    2. 5.1 Dapper 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 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 Bridge Control
      2. 7.3.2 Independent Half-Bridge Control
      3. 7.3.3 Sleep Mode
      4. 7.3.4 Power Supplies and Input Pins
      5. 7.3.5 Protection Circuits
        1. 7.3.5.1 VCC Undervoltage Lockout
        2. 7.3.5.2 Overcurrent Protection (OCP)
        3. 7.3.5.3 Thermal Shutdown (TSD)
        4. 7.3.5.4 28
    4. 7.4 Device Functional Modes
      1.      Application and Implementation
        1. 8.1 Application Information
        2. 8.2 Typical Application
          1. 8.2.1 Design Requirements
          2. 8.2.2 Detailed Design Procedure
            1. 8.2.2.1 Motor Voltage
            2. 8.2.2.2 Low-Power Operation
          3. 8.2.3 Application Curves
  8. 8 Power Supply Recommendations
    1. 8.1 Bulk Capacitance
  9. 9 Layout
    1. 9.1 Layout Guidelines
    2. 9.2 Layout Example
    3. 9.3 Power Dissipation
  10. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 Related Links
    3. 10.3 Receiving Notification of Documentation Updates
    4. 10.4 Community Resources
    5. 10.5 Trademarks
      1.      Mechanical, 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

8.1 Bulk Capacitance

Having appropriate local bulk capacitance is an important factor in motor-drive system design. It is generally beneficial to have more bulk capacitance, while the disadvantages are increased cost and physical size.

The amount of local capacitance needed depends on a variety of factors, including:

  • The highest current required by the motor system
  • The power-supply capacitance and ability to source current
  • The amount of parasitic inductance between the power supply and motor system
  • The acceptable voltage ripple
  • The type of motor used (brushed dc, brushless dc, stepper)
  • The motor braking method

The inductance between the power supply and motor drive system limits the rate at which current can change from the power supply. If the local bulk capacitance is too small, the system responds to excessive current demands or dumps from the motor with a change in voltage. When adequate bulk capacitance is used, the motor voltage remains stable and high current can be quickly supplied.

The data sheet generally provides a recommended value, but system-level testing is required to determine the appropriate size of bulk capacitor.

GUID-2D12D4CD-19DE-4313-9C6D-D5925CBDF128-low.gifFigure 8-1 Example Setup of Motor Drive System With External Power Supply

The voltage rating for bulk capacitors should be higher than the operating voltage, to provide margin for cases when the motor transfers energy to the supply