New Industry Products

3-Phase Smart Gate Driver Eval Board Suitable for Sensorless BLDC Algorithms

July 09, 2019 by Paul Shepard

The DRV8350H-EVM from Texas Instruments is a 15A, 3-phase brushless dc drive stage based on the DRV8350H gate driver and CSD19532Q5B NexFET™ power blocks.

The module has individual dc bus and phase voltage sense as well as an external, individual low-side current shunt amplifier, making this evaluation module suited for sensorless BLDC algorithms.  The module supplies MCU 3.3V and 5V power blocks from a 12V, 0.35A step down buck regulator. The driver can be configured in split rail and single rail power solutions.

The drive stage has IDRIVE configuration, along with a fault pin and protection for short circuit, thermal, shoot-through, and under voltage conditions through configurable hardware. The EVM has an entire USB to MCU environment to program and evaluate the EVM using available trapezoidal drive firmware and GUI.

DRV8350H-EVM simplified schematic

DRV8350H-EVM Features

  • 9- to 95-V operation
  • 15A continuous / 20A peak H-bridge output current
  • Complete evaluation module with hall sensor connection along with programmable MSP430F5529
  • One individual, external low-side current shunt amplifiers
  • Trapezoidal sensored and sensorless BLDC firmware available
  • Hardware interface to configure IDRIVE, MODE, VDS monitoring, and GAIN

DRV835x gate drivers

The DRV835x family of devices are highly-integrated gate drivers for three-phase brushless DC (BLDC) motor applications. These applications include field-oriented control (FOC), sinusoidal current control, and trapezoidal current control of BLDC motors. The device variants provide optional integrated current shunt amplifiers to support different motor control schemes and a buck regulator to power the gate driver or external controller.

DRV835x functional diagram (click on diagram to enlarge)

The DRV835x uses smart gate drive (SGD) architecture to decrease the number of external components that are typically necessary for MOSFET slew rate control and protection circuits. The SGD architecture also optimizes dead time to prevent shoot-through conditions, provides flexibility in decreasing electromagnetic interference by MOSFET slew rate control, and protects against gate short circuit conditions through VGS monitors. A strong gate pulldown circuit helps prevent unwanted dV/dt parasitic gate turn on events

Various pwm control modes (6x, 3x, 1x, and independent) are supported for simple interfacing to the external controller. These modes can decrease the number of outputs required of the controller for the motor driver pwm control signals. This family of devices also includes 1x pwm mode for simple sensored trapezoidal control of a BLDC motor by using an internal block commutation table.

DRV835x Features Summary

  • 9 to 100-V, Triple Half-Bridge Gate Driver
    • Optional Integrated Buck Regulator
    • Optional Triple Low-Side Current Shunt Amplifiers
  • Smart Gate Drive Architecture
    • Adjustable Slew Rate Control For EMI Performance
    • VGS Handshake and Minimum Dead-Time Insertion to Prevent Shoot-Through
    • 50-mA to 1-A Peak Source Current
    • 100-mA to 2-A Peak Sink Current
    • dV/dt Mitigation Through Strong Pulldown
  • Integrated Gate Driver Power Supplies
    • High-Side Doubler Charge Pump For 100% PWM Duty Cycle Control
    • Low-Side Linear Regulator
  • Integrated LM5008A Buck Regulator
    • 6 to 95-V Operating Voltage Range
    • 5 to 75-V, 350-mA Output Capability
  • Integrated Triple Current Shunt Amplifiers
    • Adjustable Gain (5, 10, 20, 40 V/V)
    • Bidirectional or Unidirectional Support
  • 6x, 3x, 1x, and Independent PWM Modes
    • Supports 120° Sensored Operation
  • SPI or Hardware Interface Available
  • Low-Power Sleep Mode (20 µA at VVM =48-V)
  • Integrated Protection Features
    • VM Undervoltage Lockout (UVLO)
    • Gate Drive Supply Undervoltage (GDUV)
    • MOSFET VDS Overcurrent Protection (OCP)
    • MOSFET Shoot-Through Prevention
    • Gate Driver Fault (GDF)
    • Thermal Warning and Shutdown (OTW/OTSD)
    • Fault Condition Indicator (nFAULT)