SLOSE51A June   2020  – December 2020 DRV8428E

ADVANCE INFORMATION  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1. 5.1 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
      1. 6.5.1 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
    3. 7.3 Feature Description
      1. 7.3.1 PWM Motor Drivers
      2. 7.3.2 Bridge Control
      3. 7.3.3 Current Regulation, Off-time and Decay Modes
        1. 7.3.3.1 Mixed Decay
        2. 7.3.3.2 Smart tune Dynamic Decay
        3. 7.3.3.3 Smart tune Ripple Control
        4. 7.3.3.4 Blanking time
      4. 7.3.4 Linear Voltage Regulators
      5. 7.3.5 Logic and Seven-Level Pin Diagrams
      6. 7.3.6 Protection Circuits
        1. 7.3.6.1 VM Undervoltage Lockout (UVLO)
        2. 7.3.6.2 Overcurrent Protection (OCP)
        3. 7.3.6.3 Thermal Shutdown (OTSD)
        4. 7.3.6.4 Fault Condition Summary
    4. 7.4 Device Functional Modes
      1. 7.4.1 Sleep Mode (nSLEEP = 0)
      2. 7.4.2 Operating Mode (nSLEEP = 1)
      3. 7.4.3 Functional Modes Summary
  8. 8 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 Current Regulation
        2. 8.2.2.2 Power Dissipation and Thermal Calculation
          1. 8.2.2.2.1 Application Curves
    3. 8.3 Alternate Application
      1. 8.3.1 Design Requirements
      2. 8.3.2 Detailed Design Procedure
        1. 8.3.2.1 Current Regulation
          1. 8.3.2.1.1 Stepper Motor Speed
            1. 8.3.2.1.1.1 Decay Modes
  9. 9 Power Supply Recommendations
    1. 9.1 Bulk Capacitance
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Related Links
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.3.3 Smart tune Ripple Control

GUID-9E20B1C4-B248-4910-8811-9E5276103546-low.gifFigure 7-8 Smart tune Ripple Control Decay Mode

Smart tune Ripple Control operates by setting an IVALLEY level alongside the ITRIP level. When the current level reaches ITRIP, instead of entering slow decay until the tOFF time expires, the driver enters slow decay until IVALLEY is reached. Slow decay operates similar to mode 1 in which both low-side MOSFETs are turned on allowing the current to recirculate. In this mode, tOFF varies depending on the current level and operating conditions.

This method allows much tighter regulation of the current level increasing motor efficiency and system performance. Smart tune Ripple Control can be used in systems that can tolerate a variable off-time regulation scheme to achieve small current ripple in the current regulation.

The ripple current in this decay mode is 7.5mA + 1% of the ITRIP at a specific microstep level.