SLOSE98A December   2022  – September 2023 DRV8461

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Pin Configuration and Functions
  7. 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 SPI Timing Requirements
      2. 6.5.2 STEP and DIR Timing Requirements
    6. 6.6 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Interface of Operation
      2. 7.3.2  Stepper Motor Driver Current Ratings
        1. 7.3.2.1 Peak Current Rating
        2. 7.3.2.2 RMS Current Rating
        3. 7.3.2.3 Full-Scale Current Rating
      3. 7.3.3  PWM Motor Drivers
      4. 7.3.4  Microstepping Indexer
      5. 7.3.5  Indexer Output
        1. 7.3.5.1 nHOME Output
      6. 7.3.6  Automatic Microstepping Mode
      7. 7.3.7  Custom Microstepping Table
      8. 7.3.8  Current Regulation
        1. 7.3.8.1 Internal Reference Voltage
      9. 7.3.9  Standstill Power Saving Mode
      10. 7.3.10 Current Regulation Decay Modes
        1. 7.3.10.1 Slow Decay
        2. 7.3.10.2 Mixed Decay
        3. 7.3.10.3 Smart tune Dynamic Decay
        4. 7.3.10.4 Smart tune Ripple Control
        5. 7.3.10.5 PWM OFF Time
        6. 7.3.10.6 Current Regulation Blanking Time and Deglitch Time
      11. 7.3.11 Current Sensing with External Resistor
      12. 7.3.12 Silent step decay mode
      13. 7.3.13 Auto-torque Dynamic Current Adjustment
        1. 7.3.13.1 Auto-torque Learning Routine
        2. 7.3.13.2 Current Control Loop
        3. 7.3.13.3 PD Control Loop
      14. 7.3.14 Charge Pump
      15. 7.3.15 Linear Voltage Regulator
      16. 7.3.16 VCC Voltage Supply
      17. 7.3.17 Logic Level, Tri-Level and Quad-Level Pin Diagrams
      18. 7.3.18 Spread Spectrum
      19. 7.3.19 Protection Circuits
        1. 7.3.19.1  VM Undervoltage Lockout
        2. 7.3.19.2  VCP Undervoltage Lockout (CPUV)
        3. 7.3.19.3  Logic Supply Power on Reset (POR)
        4. 7.3.19.4  Overcurrent Protection (OCP)
          1. 7.3.19.4.1 Latched Shutdown
          2. 7.3.19.4.2 Automatic Retry
        5. 7.3.19.5  Stall Detection
        6. 7.3.19.6  Open-Load Detection (OL)
        7. 7.3.19.7  Overtemperature Warning (OTW)
        8. 7.3.19.8  Thermal Shutdown (OTSD)
          1. 7.3.19.8.1 Latched Shutdown
          2. 7.3.19.8.2 Automatic Retry
        9. 7.3.19.9  Supply voltage sensing
        10. 7.3.19.10 nFAULT Output
        11. 7.3.19.11 Fault Condition Summary
      20. 7.3.20 Device Functional Modes
        1. 7.3.20.1 Sleep Mode
        2. 7.3.20.2 Disable Mode
        3. 7.3.20.3 Operating Mode
        4. 7.3.20.4 nSLEEP Reset Pulse
        5. 7.3.20.5 Functional Modes Summary
    4. 7.4 Programming
      1. 7.4.1 Serial Peripheral Interface (SPI) Communication
        1. 7.4.1.1 SPI Format
        2. 7.4.1.2 SPI for Multiple Target Devices in Daisy Chain Configuration
        3. 7.4.1.3 SPI for Multiple Target Devices in Parallel Configuration
    5. 7.5 Register Maps
      1. 7.5.1 Status Registers
        1. 7.5.1.1 FAULT (address = 0x00) [Default = 00h]
        2. 7.5.1.2 DIAG1 (address = 0x01) [Default = 00h]
        3. 7.5.1.3 DIAG2 (address = 0x02) [Default = 00h]
        4. 7.5.1.4 DIAG3 (address = 0x03) [Default = 00h]
      2. 7.5.2 Control Registers
        1. 7.5.2.1  CTRL1 (address = 0x04) [Default = 0Fh]
        2. 7.5.2.2  CTRL2 (address = 0x05) [Default = 06h]
        3. 7.5.2.3  CTRL3 (address = 0x06) [Default = 38h]
        4. 7.5.2.4  CTRL4 (address = 0x07) [Default = 49h]
        5. 7.5.2.5  CTRL5 (address = 0x08) [Default = 03h]
        6. 7.5.2.6  CTRL6 (address = 0x09) [Default = 20h]
        7. 7.5.2.7  CTRL7 (address = 0x0A) [Default = FFh]
        8. 7.5.2.8  CTRL8 (address = 0x0B) [Default = 0Fh]
        9. 7.5.2.9  CTRL9 (address = 0x0C) [Default = 10h]
        10. 7.5.2.10 CTRL10 (address = 0x0D) [Default = 80h]
        11. 7.5.2.11 CTRL11 (address = 0x0E) [Default = FFh]
        12. 7.5.2.12 CTRL12 (address = 0x0F) [Default = 20h]
        13. 7.5.2.13 CTRL13 (address = 0x10) [Default = 10h]
        14. 7.5.2.14 CTRL14 (address = 0x3C) [Default = 58h]
      3. 7.5.3 Indexer Registers
        1. 7.5.3.1 INDEX1 (address = 0x11) [Default = 80h]
        2. 7.5.3.2 INDEX2 (address = 0x12) [Default = 80h]
        3. 7.5.3.3 INDEX3 (address = 0x13) [Default = 80h]
        4. 7.5.3.4 INDEX4 (address = 0x14) [Default = 82h]
        5. 7.5.3.5 INDEX5 (address = 0x15) [Default = B5h]
      4. 7.5.4 Custom Microstepping Registers
        1. 7.5.4.1 CUSTOM_CTRL1 (address = 0x16) [Default = 00h]
        2. 7.5.4.2 CUSTOM_CTRL2 (address = 0x17) [Default = 00h]
        3. 7.5.4.3 CUSTOM_CTRL3 (address = 0x18) [Default = 00h]
        4. 7.5.4.4 CUSTOM_CTRL4 (address = 0x19) [Default = 00h]
        5. 7.5.4.5 CUSTOM_CTRL5 (address = 0x1A) [Default = 00h]
        6. 7.5.4.6 CUSTOM_CTRL6 (address = 0x1B) [Default = 00h]
        7. 7.5.4.7 CUSTOM_CTRL7 (address = 0x1C) [Default = 00h]
        8. 7.5.4.8 CUSTOM_CTRL8 (address = 0x1D) [Default = 00h]
        9. 7.5.4.9 CUSTOM_CTRL9 (address = 0x1E) [Default = 00h]
      5. 7.5.5 Auto torque Registers
        1. 7.5.5.1  ATQ_CTRL1 (address = 0x1F) [Default = 00h]
        2. 7.5.5.2  ATQ_CTRL2 (address = 0x20) [Default = 00h]
        3. 7.5.5.3  ATQ_CTRL3 (address = 0x21) [Default = 00h]
        4. 7.5.5.4  ATQ_CTRL4 (address = 0x22) [Default = 20h]
        5. 7.5.5.5  ATQ_CTRL5 (address = 0x23) [Default = 00h]
        6. 7.5.5.6  ATQ_CTRL6 (address = 0x24) [Default = 00h]
        7. 7.5.5.7  ATQ_CTRL7 (address = 0x25) [Default = 00h]
        8. 7.5.5.8  ATQ_CTRL8 (address = 0x26) [Default = 00h]
        9. 7.5.5.9  ATQ_CTRL9 (address = 0x27) [Default = 00h]
        10. 7.5.5.10 ATQ_CTRL10 (address = 0x28) [Default = 08h]
        11. 7.5.5.11 ATQ_CTRL11 (address = 0x29) [Default = 0Ah]
        12. 7.5.5.12 ATQ_CTRL12 (address = 0x2A) [Default = FFh]
        13. 7.5.5.13 ATQ_CTRL13 (address = 0x2B) [Default = 05h]
        14. 7.5.5.14 ATQ_CTRL14 (address = 0x2C) [Default = 0Fh]
        15. 7.5.5.15 ATQ_CTRL15 (address = 0x2D) [Default = 00h]
        16. 7.5.5.16 ATQ_CTRL16 (address = 0x2E) [Default = FFh]
        17. 7.5.5.17 ATQ_CTRL17 (address = 0x2F) [Default = 00h]
        18. 7.5.5.18 ATQ_CTRL18 (address = 0x30) [Default = 00h]
      6. 7.5.6 Silent Step Registers
        1. 7.5.6.1 SS_CTRL1 (address = 0x31) [Default = 00h]
        2. 7.5.6.2 SS_CTRL2 (address = 0x32) [Default = 00h]
        3. 7.5.6.3 SS_CTRL3 (address = 0x33) [Default = 00h]
        4. 7.5.6.4 SS_CTRL4 (address = 0x34) [Default = 00h]
        5. 7.5.6.5 SS_CTRL5 (address = 0x35) [Default = FFh]
  9. 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 Stepper Motor Speed
      3. 8.2.3 Application Performance Plots
      4. 8.2.4 Thermal Application
        1. 8.2.4.1 Power Dissipation
        2. 8.2.4.2 Conduction Loss
        3. 8.2.4.3 Switching Loss
        4. 8.2.4.4 Power Dissipation Due to Quiescent Current
        5. 8.2.4.5 Total Power Dissipation
        6. 8.2.4.6 Device Junction Temperature Estimation
  10. 9 Thermal Considerations
    1. 9.1 Thermal Pad
    2. 9.2 PCB Material Recommendation
  11. 10Power Supply Recommendations
    1. 10.1 Bulk Capacitance
    2. 10.2 Power Supplies
  12. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  13. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  14. 13Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.13 Auto-torque Dynamic Current Adjustment

For a typical stepper motor driver, the full-scale current is designed based on the peak load torque demand. This ensures that the motor does not lose steps any time peak load is demanded. The current therefore is constant irrespective of the load torque. As a result, when load torque is lower than the peak load, the driver and the motor dissipate some of the input power as resistive power loss as represented in Figure 7-22.

GUID-20220519-SS0I-ZWCV-ZZPL-45SRD51BT2FC-low.svgFigure 7-22 Power Loss with Conventional Stepper Driver

In most systems, the demand for peak load torque occurs only rarely. For example, in an ATM machine, the stepper motors might be needed to deliver peak load for less than 15% of their overall run time. A typical stepper driver though ends up delivering full-scale current to the motors all the time - leading to lower system efficiency due to the unwanted power loss, larger system size and shorter lifetime of components.

The Auto-torque algorithm implemented in the DRV8461 improves system efficiency by dynamically changing the output current according to the load torque. Whenever the load torque is low, the output current is lowered to reduce resistive losses; and when the load torque goes up, the output current increases immediately to prevent motor step loss. This concept is shown in Figure 7-25. As a result of improved efficiency due to auto-torque, the system runs at a lower temperature, which extends the lifetime of the components. Auto-torque can also enable the use of cheaper and smaller sized stepper motors.

GUID-20220521-SS0I-MCZJ-8Z1R-WHCNS0GGBZ8B-low.svgFigure 7-23 Power Saving with Auto-torque

The auto-torque feature is enabled by writing 1b to the ATQ_EN bit.