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

8.3.4.2 Current Regulation

The DRV8214 integrates current regulation using either a fixed off-time or a cycle-by-cycle PWM current regulation scheme. This allows the device to limit the output current in case of a motor stall, high torque, or other high current load events autonomously. The current regulation scheme is selectable by the REG_CTRL bit in I2C.

The internal current regulation can be disabled by tying IPROPI to GND and setting the VREF pin voltage greater than GND if current feedback is not required. Additionally, current regulation can also be disabled by setting IMODE to 00b as explained below. If current feedback is required and current regulation is not required, set VVREF and RIPROPI such that VIPROPI never reaches the VVREF threshold. For proper operation of the current regulation circuit, VVREF must be within the range of the VREF pin voltage specified in the Recommended Operating Conditions table.

Table 8-8 REG_CTRL Functions
Bit* Current Regulation Mode
00b Fixed Off-Time
01b Cycle-By-Cycle
Note:

*Additional REG_CTRL options 10b and 11b allow selection between motor voltage or speed regulation described in Section 8.3.7.2.1.

The current regulation threshold (ITRIP) is set through a combination of the VREF voltage (VVREF) and IPROPI output resistor (RIPROPI). This is done by comparing the voltage drop across the external RIPROPI resistor to VVREF with an internal comparator.

Equation 3. ITRIP (A) x AIPROPI (μA/A) = VVREF (V) / RIPROPI (Ω)

For example, if VVREF = 3.3 V, RIPROPI = 7500 Ω and AIPROPI = 225 μA/A, then ITRIP will be approximately 1.96 A.

VVREF must be lower than VVM by at least 1.25 V. The maximum recommended value of VVREF is 3.3 V. If INT_VREF bit is set to 1b, VVREF is internally selected with a fixed value of 500 mV.

The ITRIP comparator has both a blanking time (tBLANK) and a deglitch time (tDEG). The internal blanking time helps to prevent voltage and current transients during output switching from affecting the current regulation. These transients may be caused by a capacitor inside the motor or motor terminals. The internal deglitch time ensures that transient conditions do not prematurely trigger the current regulation. In certain cases where the transient conditions are longer than the deglitch time, placing a 10-nF capacitor on the IPROPI pin, close to the device, helps filter the transients on IPROPI output so current regulation does not prematurely trigger. The capacitor value can be modified as needed, however large capacitor values may slow down the response time of the current regulation circuit.

The IMODE bits determine the behavior of current regulation for the motor driver.

  • When IMODE is 00b, current regulation is disabled.

  • When IMODE is 01b, the device performs current regulation only during the tINRUSH time when stall detection is enabled.

  • When IMODE is 10b, current regulation is enabled at all times.

The following table summarizes the IMODE bit settings.

Table 8-9 IMODE configuration
IMODE

EN_STALL

 Description

00b

 X No current regulation at any time
01b

0b

 Current regulation at all times

1b

 Current regulation during tINRUSH only

1Xb

 X Current regulation at all times