SLLU364 may   2023 MCT8315A

 

  1.   1
  2.   Abstract
  3. 1Revision History
  4.   Trademarks
  5. 2Introduction
    1. 2.1 Hardware and GUI setup
      1. 2.1.1 Jumper Configuration
      2. 2.1.2 External Connections
      3. 2.1.3 Connecting to the GUI
        1. 2.1.3.1 Connect to computer
        2. 2.1.3.2 Connect to the GUI
        3. 2.1.3.3 Verify Hardware Connection
  6. 3Essential Controls
    1. 3.1 Recommended Default Values based on application
    2. 3.2 Device and Pin Configuration
      1. 3.2.1 Speed input mode
    3. 3.3 Algorithm configuration – Motor speed
      1. 3.3.1 Maximum motor electrical speed (Hz)
    4. 3.4 Control Configuration
      1. 3.4.1 Cycle by cycle current limit (ILIMIT)
    5. 3.5 Testing for successful startup into closed loop
    6. 3.6 Fault handling
      1. 3.6.1 Abnormal Speed [ABN_SPEED]
      2. 3.6.2 Loss of Sync [LOSS_OF_SYNC]
      3. 3.6.3 No Motor Fault [NO_MTR]
      4. 3.6.4 Cycle by cycle current limit [CBC_ILIMIT]
  7. 4Basic Controls
    1. 4.1 Device and pin configuration
      1. 4.1.1 Power saver or sleep mode for battery operated applications
      2. 4.1.2 Direction and Brake pin override
    2. 4.2 System level configuration
      1. 4.2.1 Tracking motor speed feedback in real time
      2. 4.2.2 Monitoring power supply voltage fluctuations for normal motor operation
    3. 4.3 Control configurations
      1. 4.3.1  Initial speed detection of the motor for reliable motor resynchronization
      2. 4.3.2  Unidirectional motor drive detecting backward spin
      3. 4.3.3  Preventing back spin of rotor during startup
      4. 4.3.4  Faster startup timing
      5. 4.3.5  Improving speed regulation
      6. 4.3.6  Stopping motor quickly
      7. 4.3.7  Faster deceleration
      8. 4.3.8  Preventing supply voltage overshoot during motor stop and deceleration
      9. 4.3.9  Protecting against rotor lock or stall condition
      10. 4.3.10 Maximizing thermal efficiency and increasing thermal performance
      11. 4.3.11 Mitigating Electromagnetic Interference (EMI)
      12. 4.3.12 Improving Motor efficiency
      13. 4.3.13 Limiting and regulating supply power

4.3.6 Stopping motor quickly

MCT8315A provides two options for applications that require stopping the motor quickly.

Option 1: Stopping motor quickly while spinning in closed loop.

Motor can be stopped by issuing 0% input speed duty cycle.

Step 1: Configure closed loop deceleration [CL_DEC] to a value that is same as closed loop acceleration [CL_ACC].

Step 2: Configure Motor stop option [MTR_STOP] to either High side or low side braking.

Step 3: Set the active spin brake threshold [ACT_SPIN_BRK_THR] to a value such that Overcurrent protection fault does not get triggered. Check GATE_DRIVER_FAULT_STATUS (register address: 0x000000E0) bit 28 for Overcurrent protection fault status.

Step 4: Configure Recirculation Brake time [RECIR_BRK_TIME] to a value such that motor is stopped completely. Recirculation brake time might be higher for motors with higher inertia.

Step 5: Enable Fast deceleration [FAST_DECEL_EN].

Note: Fast deceleration will be active till the input speed duty cycle decelerates to active spin brake threshold [ACT_SPIN_BRK_THR]. Device will engage High side or low side braking when the input speed duty cycle is below the active spin brake threshold [ACT_SPIN_BRK_THR].

Option 2: Stopping motor quickly during all stages of motor operation.

Step 1: Configure closed loop deceleration [CL_DEC] to a value that is same as closed loop acceleration [CL_ACC].

Step 2: Configure brake input [BRAKE_INPUT] to “Hardware pin brake” to apply brake using the BRAKE pin. Use Brake switch S1 in MCx8316AEVM to pull the BRAKE pin HIGH or LOW. MCT8315A applies brake when BRAKE pin is pulled HIGH. Configure brake input [BRAKE_INPUT] to “Overwrite Hardware pin with Active Brake” to apply brake using I2C.

Step 3: Set the brake duty threshold [BRAKE_DUTY_THRESHOLD] to a value such that Overcurrent protection fault does not get triggered. Check GATE_DRIVER_FAULT_STATUS (register address: 0x000000E0) bit 28 for Overcurrent protection fault status.

Step 4: Enable Fast deceleration [FAST_DECEL_EN].

Note: Fast deceleration will be active till the input speed duty cycle decelerates to brake duty threshold [BRAKE_DUTY_THRESHOLD]. Device will engage High side or low side braking when the input speed duty cycle is below the brake duty threshold [BRAKE_DUTY_THRESHOLD].