Robotics and Automation Systems Reference Design KitNovember 22, 2019 by Paul Shepard
The EVALKIT-ROBOT-1 from STMicroelectronics is an evaluation kit offering a ready-to-use servo brushless solution for robotics and industrial automation systems. It includes a three-phase brushless dc motor (BLDC). This evaluation kit also incorporates the STSPIN32F0A, a system-in-package providing an integrated solution suitable for driving three-phase BLDCs using different driving modes.
Due to the high integration level of the STSPIN32F0A, the control board provides a powerful power stage, the analog circuitry implementing current sensing and overcurrent protection and a Cortex-M0 microcontroller performing a Field-Oriented Control with closed-loop positioning. All packed into a 40mm x 40mm footprint.
The maxon EC-i 40 three-phase BLDC motor, as a result of the optimized magnetic circuit, offers a very high torque density and very low cogging torque. In combination with the maxon ENX 16 EASY 1024 pulses incremental encoder, it is a good choice for reliable, robust and high-precision position and speed control.
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- 36V / 6A-peak power stage
- STSPIN32F0A advanced 3-phase motor controller embedding Cortex-M0 MCU
- STL7DN6LF3 60V, 35mΩ Dual N-channel MOSFETs
- Hall sensors
- Position control loop based on Field Oriented Control
- MODBUS communication protocol through RS-485
- Extremely compact footprint (40mm x 40mm)
- maxon EC-i 40 100 W 3-phase brushless dc motor
- maxon ENX 16 EASY 1024-pulse incremental encoder
The STSPIN32F0A embeds a triple half-bridge gate driver able to drive power MOSFETs with a current capability of 600 mA (sink and source). The high- and low-side switches of same half-bridge cannot be simultaneously driven high due to an integrated interlocking function.
An internal dc-dc buck converter provides the 3.3V voltage suitable to supply both the MCU and external components. An internal LDO linear regulator provides the supply voltage for gate drivers. The integrated operational amplifiers are available for the signal conditioning, e.g. the current sensing across the shunt resistors. A comparator with a programmable threshold is integrated to perform the overcurrent protection.
The integrated MCU (STM32F031C6 with extended temperature range, suffix 7 version) allows performing field-oriented control, the 6-step sensorless and other advanced driving algorithms. It has the write-protection and read-protection feature for the embedded Flash memory to protect against unwanted writing and/or reading. It is possible to download the firmware on-the-field through the serial interface thanks to the embedded bootloader.
The STSPIN32F0A device also features overtemperature and undervoltage lockout protections and can be put in the standby mode to reduce the power consumption. The device provides 16 general-purpose I/O ports (GPIO) with the 5V tolerant capability, one 12-bit analog-to-digital converter with up to 9 channels performing conversions in a single-shot or scan modes, 5 synchronizable general-purpose timers and supports an easy to use debugging serial interface (SWD).
Key Features of the STSPIN32F0A
- Extended operating voltage from 6.7- to 45-V
- Three-phase gate drivers
- 600 mA sink/source
- Integrated bootstrap diodes
- Cross-conduction prevention
- 32-bit ARM® Cortex®-M0 core:
- Up to 48MHz clock frequency
- 4-kByte SRAM with HW parity
- 32-kByte Flash memory with option bytes used for write/readout protection
- Availability FW bootloader
- 3V dc-dc buck converter regulator with overcurrent, short-circuit, and thermal protection
- 12V LDO linear regulator with thermal protection
- 16 general-purpose I/O ports (GPIO)
- 5 general-purpose timers
- 12-bit ADC converter (up to 9 channels)
- I2C, USART and SPI interfaces
- 3 rail-to-rail operation amplifiers for signal conditioning
- Comparator for overcurrent protection with programmable threshold
- Standby mode for low power consumption
- UVLO protection on each power supply:
- VM, VDD, VREG and VBOOTx
- On-chip debug support via SWD
- Extended temperature range: -40 to +125 °C