75V/10A Protected Full-Bridge Power Stage Reference Design for Bipolar Stepper Drives

1 января 2018

Stepper drives are used in many applications operating typically from 12VDC to 48VDC. TI offers a rich family of stepper motor driver solutions with industry standard step/direction and parallel control interfaces. For applications which require higher torque and power, often voltages above 48VDC, up to 100VDC are used. The TIDA-00210 provides a solution for such stepper drives. The TIDA-00210 uses two protected full-bridge power stages based on TIDA-00365 in parallel configuration. Each full-bridge operates nominal 75VDC and 10Arms phase current and features bipolar high-side current sensing leveraging a 100V full-bridge gate driver SM72295 with integrated amplifiers and four 100V NexFET power MOSFETs with ultra-low gate charge and small SON5x6 package with low thermal resistance. The power stage is fully protected against over-temperature, over-current and short-circuit between the motor terminals and motor terminals to ground. Onboard power supplies provide a 12V and a 3.3V rail for the gate driver and signal chain. The host processor interface is 3.3V I/O to connect a host MCU like C2000 Piccolo for stepper motor control.

Особенности

Protected full-bridge power stage with input voltage up to 100VDC (75VDC nominal) and 10Arms phase current. BOM reduction using SM72295 100V full-bridge gate driver with integrated amplifiers used for high-side bipolar phase current sensing, supporting up to 256 micro steps. 95% efficiency at 16 kHz PWM, nominal load with very low switching losses to support higher PWM frequencies too. No heatsink required at 25C ambient and nominal load thanks to TI NexFET power MOSFET. Full-bridge optimized for low EMI thanks to NexFET’s fast turn-on and turn-off switching time, 25ns with no overshoot on switch-node voltages. Hardware protected against over-temperature, over-current and short circuit between phase to phase and phase to GND, as well as UVLO. Thresholds are custom configurable in HW. 3.3V host processor interface allow MCU like C2000 to implement custom stepper motor control. The complementary PWM inputs and bipolar high-side current sense buffered 0-3.3V analog output allow for precise phase current control. Phase to GND voltage feedback signals allow for back EMF sensing and stall detection. An Enable signals allows the MCU to turn-on and turn-off the power stage.