SLVSH04 November   2023 DRV8214

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Device Comparison
  7. 6 Pin Configuration and Functions
  8. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 I2C Timing Requirements
    7. 7.7 Timing Diagrams
    8. 7.8 Typical Operating Characteristics
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 External Components
      2. 8.3.2 Summary of Features
      3. 8.3.3 Bridge Control
      4. 8.3.4 Current Sense and Regulation (IPROPI)
        1. 8.3.4.1 Current Sensing and Current Mirror Gain Selection
        2. 8.3.4.2 Current Regulation
          1. 8.3.4.2.1 Fixed Off-Time Current Regulation
          2. 8.3.4.2.2 Cycle-By-Cycle Current Regulation
      5. 8.3.5 Stall Detection
      6. 8.3.6 Ripple Counting
        1. 8.3.6.1 Ripple Counting Parameters
          1. 8.3.6.1.1  Motor Resistance Inverse
          2. 8.3.6.1.2  Motor Resistance Inverse Scale
          3. 8.3.6.1.3  KMC Scaling Factor
          4. 8.3.6.1.4  KMC
          5. 8.3.6.1.5  Filter Damping Constant
          6. 8.3.6.1.6  Filter Input Scaling Factor
          7. 8.3.6.1.7  Ripple Count Threshold
          8. 8.3.6.1.8  Ripple Count Threshold Scale
          9. 8.3.6.1.9  T_MECH_FLT
          10. 8.3.6.1.10 VSNS_SEL
          11. 8.3.6.1.11 Error Correction
            1. 8.3.6.1.11.1 EC_FALSE_PER
            2. 8.3.6.1.11.2 EC_MISS_PER
        2. 8.3.6.2 RC_OUT Output
        3. 8.3.6.3 Ripple Counting with nFAULT
      7. 8.3.7 Motor Voltage and Speed Regulation
        1. 8.3.7.1 Internal Bridge Control
        2. 8.3.7.2 Setting Speed/Voltage Regulation Parameters
          1. 8.3.7.2.1 Speed and Voltage Set
          2. 8.3.7.2.2 Speed Scaling Factor
        3. 8.3.7.3 Soft-Start and Soft-Stop
          1. 8.3.7.3.1 TINRUSH
      8. 8.3.8 Protection Circuits
        1. 8.3.8.1 Overcurrent Protection (OCP)
        2. 8.3.8.2 Thermal Shutdown (TSD)
        3. 8.3.8.3 VCC Undervoltage Lockout (UVLO)
        4. 8.3.8.4 Overvoltage Protection (OVP)
        5. 8.3.8.5 nFAULT Output
    4. 8.4 Device Functional Modes
      1. 8.4.1 Active Mode
      2. 8.4.2 Low-Power Sleep Mode
      3. 8.4.3 Fault Mode
    5. 8.5 Programming
      1. 8.5.1 I2C Communication
        1. 8.5.1.1 I2C Write
        2. 8.5.1.2 I2C Read
    6. 8.6 Register Map
      1. 8.6.1 DRV8214_STATUS Registers
      2. 8.6.2 DRV8214_CONFIG Registers
      3. 8.6.3 DRV8214_CTRL Registers
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application: Brushed DC Motor
      1. 9.2.1 Design Requirements
      2. 9.2.2 Stall Detection
        1. 9.2.2.1 Application Description
          1. 9.2.2.1.1 Stall Detection Timing
          2. 9.2.2.1.2 Hardware Stall Threshold Selection
      3. 9.2.3 Ripple Counting Application
        1. 9.2.3.1 Tuning Ripple Counting Parameters
          1. 9.2.3.1.1 Resistance Parameters
          2. 9.2.3.1.2 KMC and KMC_SCALE
            1. 9.2.3.1.2.1 Case I
            2. 9.2.3.1.2.2 Case II
              1. 9.2.3.1.2.2.1 Method 1: Tuning from Scratch
                1. 9.2.3.1.2.2.1.1 Tuning KMC_SCALE
                2. 9.2.3.1.2.2.1.2 Tuning KMC
              2. 9.2.3.1.2.2.2 Method 2: Using the Proportionality factor
                1. 9.2.3.1.2.2.2.1 Working Example
          3. 9.2.3.1.3 Advanced Parameters
            1. 9.2.3.1.3.1 Filter Constants
              1. 9.2.3.1.3.1.1 FLT_GAIN_SEL
              2. 9.2.3.1.3.1.2 FLT_K
            2. 9.2.3.1.3.2 T_MECH_FLT
            3. 9.2.3.1.3.3 VSNS_SEL
            4. 9.2.3.1.3.4 Additional Error Corrector Parameters
              1. 9.2.3.1.3.4.1 EC_FALSE_PER
              2. 9.2.3.1.3.4.2 EC_MISS_PER
      4. 9.2.4 Motor Voltage
      5. 9.2.5 Motor Current
      6. 9.2.6 Application Curves
  11. 10Power Supply Recommendations
    1. 10.1 Bulk Capacitance
  12. 11Layout
    1. 11.1 Layout Guidelines
  13. 12Mechanical, Packaging, and Orderable Information
    1. 12.1 Tape and Reel Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information
9.2.3.1.2.2.2 Method 2: Using the Proportionality factor

This method utilises the factor of proportionality that associates KMC and KMC_SCALE with the ripple speed, ωripple. ωripple is directly proportional to KMC_SCALE but varies inversely with KMC. Let kd be a dummy constant. We have:

Equation 13. ωripple=kdKMC_SCALEKMC

Using the subscript 'def' to denote default, we have the following equation for default values of KMC and KMC_SCALE:

Equation 14. ωdef=kdKMC_SCALEdefKMCdef

Using the subscript 'tuned', we similarly have the following equation for tuned values of KMC and KMC_SCALE:

Equation 15. ωtuned=kdKMC_SCALEtunedKMCtuned

Taking the ratio of the two equations above, the dummy constant, kd, cancels out:

Equation 16. ωtunedωdef=KMC_SCALEtunedKMCtuned×KMCdefKMC_SCALEdef

At this point, the following is known:

  1. KMC_SCALEdef = 11b (24 x 213) is the default value of KMC_SCALE from the register map.
  2. KMCdef = 163 is the default value of KMC from the register map.
  3. ωtuned is the actual value of the ripple speed in rad/s. Please refer to step 1 of the KMC_SCALE Tuning Method 1 for obtaining this value.

To obtain ωdef, select a value of W_SCALE based on step 3 of KMC_SCALE Tuning Method 1. Next, convert the ripple speed on the SPEED register obtained using KMC_SCALEdef and KMCdef into rad/s by multiplying SPEED with W_SCALE. For example, if SPEED reads 0x04 and W_SCALE is set to 10b (corresponds to 64 rad/s), then ripple speed in rad/s = 4*64 = 256 rad/s.

Plugging the four values above and simplifying, we get a ratio of KMC_SCALEtuned and KMCtuned as a constant number. Select KMC_SCALEtuned from the four available values such that KMCtuned has the highest bit precision within limits (0 to 255). A working example is shown below.