SLVSE65C July   2018  – December 2023 DRV8847

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
    6. 6.6 I2C Timing Requirements
    7. 6.7 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 PWM Motor Drivers
      2. 7.3.2 Bridge Operation
        1. 7.3.2.1 Forward Operation
        2. 7.3.2.2 Reverse Operation
        3. 7.3.2.3 Coast Operation (Fast Decay)
        4. 7.3.2.4 Brake Operation (Slow Decay)
      3. 7.3.3 Bridge Control
        1. 7.3.3.1 4-Pin Interface
        2. 7.3.3.2 2-Pin Interface
        3. 7.3.3.3 Parallel Bridge Interface
        4. 7.3.3.4 Independent Bridge Interface
      4. 7.3.4 Current Regulation
      5. 7.3.5 Current Recirculation and Decay Modes
      6. 7.3.6 Torque Scalar
      7. 7.3.7 Stepping Modes
        1. 7.3.7.1 Full-Stepping Mode (4-Pin Interface)
        2. 7.3.7.2 Full-Stepping Mode (2-Pin Interface)
        3. 7.3.7.3 Half-Stepping Mode (With Non-Driving Fast Decay)
        4. 7.3.7.4 Half-Stepping Mode (With Non-Driving Slow Decay)
      8. 7.3.8 Motor Driver Protection Circuits
        1. 7.3.8.1 Overcurrent Protection (OCP)
          1. 7.3.8.1.1 OCP Automatic Retry (Hardware Device and Software Device (OCPR = 0b))
          2. 7.3.8.1.2 OCP Latch Mode (Software Device (OCPR = 1b))
          3. 7.3.8.1.3 42
        2. 7.3.8.2 Thermal Shutdown (TSD)
        3. 7.3.8.3 VM Undervoltage Lockout (VM_UVLO)
        4. 7.3.8.4 Open Load Detection (OLD)
          1. 7.3.8.4.1 Full-Bridge Open Load Detection
          2. 7.3.8.4.2 Load Connected to VM
          3. 7.3.8.4.3 Load Connected to GND
    4. 7.4 Device Functional Modes
    5. 7.5 Programming
      1. 7.5.1 I2C Communication
        1. 7.5.1.1 I2C Write
        2. 7.5.1.2 I2C Read
      2. 7.5.2 Multi-Slave Operation
    6. 7.6 Register Map
      1. 7.6.1 Slave Address Register (Address = 0x00) [reset = 0x60]
      2. 7.6.2 IC1 Control Register (Address = 0x01) [reset = 0x00]
      3. 7.6.3 IC2 Control Register (Address = 0x02) [reset = 0x00]
      4. 7.6.4 Slew-Rate and Fault Status-1 Register (Address = 0x03) [reset = 0x40]
      5. 7.6.5 Fault Status-2 Register (Address = 0x04) [reset = 0x00]
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Stepper Motor Application
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Stepping Modes
            1. 8.2.1.2.1.1 Full-Stepping Operation
            2. 8.2.1.2.1.2 Half-Stepping Operation with Fast Decay
            3. 8.2.1.2.1.3 Half-Stepping Operation with Slow Decay
          2. 8.2.1.2.2 Current Regulation
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Dual BDC Motor Application
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
          1. 8.2.2.2.1 Motor Voltage
          2. 8.2.2.2.2 Current Regulation
          3. 8.2.2.2.3 Sense Resistor
      3. 8.2.3 Open Load Implementation
        1. 8.2.3.1 Open Load Detection Circuit
        2. 8.2.3.2 OLD for Ground Connected Load
          1. 8.2.3.2.1 Half Bridge Open
          2. 8.2.3.2.2 Half Bridge Short
          3. 8.2.3.2.3 Load Connected
        3. 8.2.3.3 OLD for Supply (VM) Connected Load
          1. 8.2.3.3.1 Half Bridge Open
          2. 8.2.3.3.2 Half Bridge Short
          3. 8.2.3.3.3 Load Connected
        4. 8.2.3.4 OLD for Full Bridge Connected Load
          1. 8.2.3.4.1 Full Bridge Open
            1. 8.2.3.4.1.1 High side comparator of half-bridge-1 (OL1_HS)
            2. 8.2.3.4.1.2 Low side comparator of half-bridge-2 (OL2_LS)
          2. 8.2.3.4.2 Full Bridge Short
            1. 8.2.3.4.2.1 High side comparator of half-bridge-1 (OL1_HS)
            2. 8.2.3.4.2.2 Low side comparator of half-bridge-2 (OL2_LS)
          3. 8.2.3.4.3 Load Connected in Full Bridge
            1. 8.2.3.4.3.1 High side comparator of half-bridge-1 (OL1_HS)
            2. 8.2.3.4.3.2 Low side comparator of half-bridge-2 (OL2_LS)
  10.   Power Supply Recommendations
    1. 9.1 Bulk Capacitance Sizing
  11. 9 Layout
    1. 9.1 Layout Guidelines
    2. 9.2 Layout Example
    3. 9.3 Thermal Considerations
      1. 9.3.1 Maximum Output Current
      2. 9.3.2 Thermal Protection
    4. 9.4 Power Dissipation
  12. 10Device and Documentation Support
    1. 10.1 Device Support (Optional)
      1. 10.1.1 Development Support (Optional)
      2. 10.1.2 Device Nomenclature (Optional)
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
    3. 10.3 Receiving Notification of Documentation Updates
    4. 10.4 Community Resources
    5. 10.5 Trademarks
  13. 11Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • PW|16
  • PWP|16
  • RTE|16
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.4 Current Regulation

The current through the motor windings is regulated by a fixed off-time PWM current regulation circuit. With brushed DC motors, current regulation can be used to limit the stall current (which is also the start-up current) of the motor.

Current regulation works as follows: When an H-bridge is enabled, current rises through the winding at a rate dependent on the supply voltage and inductance of the winding. If the current reaches the current trip threshold, the bridge disables the current for a time tOFF before starting the next PWM cycle.

Note:

Immediately after the current is enabled, the voltage on the ISENxx pin is ignored for a while (tBLANK) before enabling the current sense circuitry. This blanking time also sets the minimum on-time of the PWM cycle.

The PWM trip current is set by a comparator which compares the voltage across a current sense resistor connected to the ISENxx pin with a reference voltage. This reference voltage (VTRIP) is generated on-chip and decides the current trip level.

The full-scale trip current in a winding is calculated as shown in Equation 1.

Equation 1. GUID-340A4D9A-80B7-4572-93BF-FDDBDE690500-low.gif

where

  • ITRIP is the regulated current.
  • VTRIP is the internally generated trip voltage.
  • RSENSExx is the resistance of the sense resistor.
  • Torque is the torque scalar, the value of which depends on the input on the TRQ pin. TRQ = 100% for TRQ pin connected to GND (DRV8847) or TRQ bit set to 0 (DRV8847S) and TRQ = 50% connected to VEXT (DRV8847) or TRQ bit set to 1 (DRV8847S).

For example, if the VTRIP voltage is 150 mV and the value of the sense resistor is 150 mΩ, the full-scale trip current is 1 A (150 mV / (150 mΩ) = 1 A).

Note:

If the current control is not needed, connect the ISENxx pins directly to the ground.