SLVSAS8D April   2011  – November 2015 DRV8843

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  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 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 PWM Motor Drivers
    4. 7.4 Device Functional Modes
      1. 7.4.1 Bridge Control
      2. 7.4.2 Current Regulation
      3. 7.4.3 Decay Mode During Current Chopping
      4. 7.4.4 Blanking Time
      5. 7.4.5 nRESET and nSLEEP Operation
      6. 7.4.6 Protection Circuits
        1. 7.4.6.1 Overcurrent Protection (OCP)
        2. 7.4.6.2 Thermal Shutdown (TSD)
        3. 7.4.6.3 Undervoltage Lockout (UVLO)
  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 Decay Modes
        3. 8.2.2.3 Sense Resistor
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
    1. 9.1 Bulk Capacitance
    2. 9.2 Power Supply and Logic Sequencing
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
      1. 10.3.1 Thermal Protection
      2. 10.3.2 Power Dissipation
      3. 10.3.3 Heatsinking
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Community Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

9 Power Supply Recommendations

The DRV8843 is designed to operate from an input voltage supply (VMx) range between 8.2 and 45 V. Two
0.1-µF ceramic capacitors rated for VMx must be placed as close as possible to the VMA and VMB pins respectively (one on each pin). In addition to the local decoupling caps, additional bulk capacitance is required and must be sized accordingly to the application requirements.

9.1 Bulk Capacitance

Bulk capacitance sizing is an important factor in motor drive system design. It is dependent on a variety of factors including:

  • Type of power supply
  • Acceptable supply voltage ripple
  • Parasitic inductance in the power supply wiring
  • Type of motor (brushed DC, brushless DC, stepper)
  • Motor startup current
  • Motor braking method

The inductance between the power supply and motor drive system will limit the rate current can change from the power supply. If the local bulk capacitance is too small, the system will respond to excessive current demands or dumps from the motor with a change in voltage. You should size the bulk capacitance to meet acceptable voltage ripple levels.

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

DRV8843 app_motor_drive_slvs997.gif Figure 11. Setup of Motor Drive System With External Power Supply

9.2 Power Supply and Logic Sequencing

There is no specific sequence for powering-up the DRV8843. It is okay for digital input signals to be present before VMx is applied. After VMx is applied to the device, it begins operation based on the status of the control pins.