Single-chip, low pin-count MCUs control multiple motors

October 07, 2016 // By Graham Prophet
Toshiba has developed a range of microcontrollers that allow a single-chip, with a low pin-count (32 to 64 pins), to control multiple motors. The MK4 group is the second offering in Toshiba’s TXZ family of high-speed, low power consumption microcontrollers that incorporate the ARM Cortex-M core.

The MCUs meet the need to reduce energy and save space in motor control applications ranging from home appliances such as washing machines and refrigerators to power tools, ventilation fans, electric bicycles and industrial motion control.


Until now, driving two motors typically required an MCU in a 100-pin type package. Toshiba’s 64-pin TXZ family products, however, can control two motors thanks to the ability to detect motor position via an integrated, high-speed AD converter with a 0.5 μsec conversion speed.


The devices are based on the ARM Cortex-M4F operating at up to 80 MHz and incorporating a floating point processing unit. As well as the high-precision ADC, the devices feature high-speed Flash memory with 80 MHz operation, a co-processor for Toshiba’s original vector engine, and 3-channel op-amps with selectable gain. Together, they ensure the new products realise efficient motor control while improving the power factor and system control.


Devices in the TXZ family support the RAMScope interface, which can confirm parameters in real time without stopping motors by loading parameters relevant to motor control to RAM. A self-diagnostic function that confirms the reference voltage of the ADC, and a CRC arithmetic circuit that identifies incorrect detection for every read operation of the memory are also incorporated. This supports load mitigation of the software process required for functional safety.


With pin counts from 32 pins to 64 pins, the new devices are available with flash memory capacities from 64 kB to 128 kB. Communication options comprise UART, TSPI and I ²C interfaces, while I/O ports range from 24 to 52. Operating voltage range is from 4.5V to 5.5V. Toshiba’s integrated Advanced Vector Engine Plus (A-VE+) supports vector control and dead-time compensation, while an advanced programmable motor control (A-PMD) circuit delivers 3-phase output and supports 3-phase interleaved PFC.