STMicroelectronics has introduced two new plug-and-play boards for controlling three-phase Brushless DC (BLDC) motors powered by lithium-ion batteries operating at up to 56V. Use of the boards eases the development of compact, reliable motors for cordless home and garden power tools.
Based on ST’s STSPIN32 motor-control systems-in-package, the STEVAL-PTOOL1V1 and STEVAL-PTOOL2V1 evaluation boards are ideal for use in cordless power-tool designs because of their small dimensions and low stand-by current.
Firmware is supplied with the boards for six-step motor commutation using Hall-effect rotor-position sensing, which ensures low torque ripple and high power efficiency.
The STEVAL-PTOOL1V1 is for equipment powered by li-ion battery packs containing from two to six cells, and is able to support motors operating at up to 45V. It has a 70mm x 30mm footprint and supplies up to 15A continuous current. Stand-by current is less than 1µA.
At the heart of the board is the STSPIN32F0B motor controller, which contains an STM32F0* microcontroller, three-phase half-bridge gate driver, 12V and 3.3V voltage regulators, and an operational amplifier for current sensing. It also includes protection functions such as programmable over-current protection, cross-conduction prevention, and under-voltage lock-out.
The STEVAL-PTOOL2V1 is for batteries containing from eight to 15 cells. Its power stage is based on 80V STL130N8F7 power MOSFETs. It can supply up to 19A continuous current. It is controlled by ST’s STSPIN32F0252 motor controller, which contains a three-phase 250V gate driver, an STM32F0* MCU, and a comparator which offers fast and flexible over-current protection.
The STSPIN32F0252’s rugged design allows Output pins to resist below-ground spikes down to -120V, which enhances the reliability of power tools. Featuring on-board bus-voltage sensing, the STEVAL-PTOOL2V1 board’s footprint measures 80mm x 58mm.
Both boards provide a potentiometer for speed variation, inputs for trigger and rotation-direction setting, thermal shut-down, and protection against reverse-biasing of power-stage outputs. They are supplied with a mounted heat-sink.
* STM32 is a registered and/or unregistered trademark of STMicroelectronics International NV or its affiliates in the EU and/or elsewhere. In particular, STM32 is registered at the US Patent and Trademark Office.