SLVSH03 December   2023 DRV8234

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  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
    6. 6.6 I2C Timing Requirements
    7. 6.7 Timing Diagrams
    8. 6.8 Typical Operating Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 External Components
      2. 7.3.2 Summary of Features
      3. 7.3.3 Bridge Control
      4. 7.3.4 Current Sense and Regulation (IPROPI)
        1. 7.3.4.1 Current Sensing
        2. 7.3.4.2 Current Regulation
          1. 7.3.4.2.1 Fixed Off-Time Current Regulation
          2. 7.3.4.2.2 Cycle-By-Cycle Current Regulation
      5. 7.3.5 Stall Detection
      6. 7.3.6 Ripple Counting
        1. 7.3.6.1 Ripple Counting Parameters
          1. 7.3.6.1.1  Motor Resistance Inverse
          2. 7.3.6.1.2  Motor Resistance Inverse Scale
          3. 7.3.6.1.3  KMC Scaling Factor
          4. 7.3.6.1.4  KMC
          5. 7.3.6.1.5  Filter Damping Constant
          6. 7.3.6.1.6  Filter Input Scaling Factor
          7. 7.3.6.1.7  Ripple Count Threshold
          8. 7.3.6.1.8  Ripple Count Threshold Scale
          9. 7.3.6.1.9  T_MECH_FLT
          10. 7.3.6.1.10 VSNS_SEL
          11. 7.3.6.1.11 Error Correction
            1. 7.3.6.1.11.1 EC_FALSE_PER
            2. 7.3.6.1.11.2 EC_MISS_PER
        2. 7.3.6.2 RC_OUT Output
        3. 7.3.6.3 Ripple Counting with nFAULT
      7. 7.3.7 Motor Voltage and Speed Regulation
        1. 7.3.7.1 Internal Bridge Control
        2. 7.3.7.2 Setting Speed/Voltage Regulation Parameters
          1. 7.3.7.2.1 Speed and Voltage Set
          2. 7.3.7.2.2 Speed Scaling Factor
        3. 7.3.7.3 Soft-Start and Soft-Stop
          1. 7.3.7.3.1 TINRUSH
      8. 7.3.8 Protection Circuits
        1. 7.3.8.1 Overcurrent Protection (OCP)
        2. 7.3.8.2 Thermal Shutdown (TSD)
        3. 7.3.8.3 VM Undervoltage Lockout (VM UVLO)
        4. 7.3.8.4 Overvoltage Protection (OVP)
        5. 7.3.8.5 nFAULT Output
    4. 7.4 Device Functional Modes
      1. 7.4.1 Active Mode
      2. 7.4.2 Low-Power Sleep Mode
      3. 7.4.3 Fault Mode
    5. 7.5 Programming
      1. 7.5.1 I2C Communication
        1. 7.5.1.1 I2C Write
        2. 7.5.1.2 I2C Read
    6. 7.6 Register Map
      1. 7.6.1 DRV8234_STATUS Registers
      2. 7.6.2 DRV8234_CONFIG Registers
      3. 7.6.3 DRV8234_CTRL Registers
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application: Brushed DC Motor
      1. 8.2.1 Design Requirements
      2. 8.2.2 Stall Detection
        1. 8.2.2.1 Application Description
          1. 8.2.2.1.1 Stall Detection Timing
          2. 8.2.2.1.2 Hardware Stall Threshold Selection
      3. 8.2.3 Ripple Counting Application
        1. 8.2.3.1 Tuning Ripple Counting Parameters
          1. 8.2.3.1.1 Resistance Parameters
          2. 8.2.3.1.2 KMC and KMC_SCALE
            1. 8.2.3.1.2.1 Case I
            2. 8.2.3.1.2.2 Case II
              1. 8.2.3.1.2.2.1 Method 1: Tuning from Scratch
                1. 8.2.3.1.2.2.1.1 Tuning KMC_SCALE
                2. 8.2.3.1.2.2.1.2 Tuning KMC
              2. 8.2.3.1.2.2.2 Method 2: Using the Proportionality factor
                1. 8.2.3.1.2.2.2.1 Working Example
          3. 8.2.3.1.3 Advanced Parameters
            1. 8.2.3.1.3.1 Filter Constants
              1. 8.2.3.1.3.1.1 FLT_GAIN_SEL
              2. 8.2.3.1.3.1.2 FLT_K
            2. 8.2.3.1.3.2 T_MECH_FLT
            3. 8.2.3.1.3.3 VSNS_SEL
            4. 8.2.3.1.3.4 Additional Error Corrector Parameters
              1. 8.2.3.1.3.4.1 EC_FALSE_PER
              2. 8.2.3.1.3.4.2 EC_MISS_PER
      4. 8.2.4 Motor Voltage
      5. 8.2.5 Motor Current
      6. 8.2.6 Application Curves
  10. 9 Power Supply Recommendations
    1. 9.1 Bulk Capacitance
  11. 10Layout
    1. 10.1 Layout Guidelines
  12. 11Device and Documentation Support
    1. 11.1 Receiving Notification of Documentation Updates
    2. 11.2 Support Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  13. 12Revision History

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Orderable Information

7.3.7 Motor Voltage and Speed Regulation

The DRV8234 provides the ability to regulate the voltage applied to the motor winding or to regulate the speed of the motor. This feature allows constant motor speed to be maintained even when operating from a varying supply voltage such as a discharging battery. The DRV8234 uses a pulse-width modulation (PWM) technique instead of a linear circuit to minimize current consumption and maximize battery life.

The intended voltage or speed can be programmed by the WSET_VSET bits. Refer to Section 7.3.7.2.1 for further explanation.

Four ranges of motor speed can be selected using the W_SCALE bits to support low, moderate and high speed applications. The speed regulation loop compares the motor speed estimated by the ripple counting algorithm with the user definded target speed. The following section describes the internal bridge control logic taking voltage regulation as an example, but is also applicable for speed regulation.

Figure 7-15 shows the closed loop PI control for regulating speed and voltage.

GUID-20231004-SS0I-TFX1-QWWL-SZ7HFPJLBGQW-low.svgFigure 7-15 Speed and Voltage Regulation with PI Control