MCUs Add Tri-Phase Motor Controllers

The newest members of the 8-bit ST7MC microcontroller family control 3-phase induction and brushless permanent-magnet motors, as well as compressors. Four devices in the group employ the company's on-chip motor control peripheral, the MTC, which consists of a tri-phase PWM multiplexed on six high-sink outputs. The MTC also includes a back EMF, zero-crossing detector and co-processor unit that provide sensor-less control of dc brushless permanent-magnet motors. Input pins can be configured for Hall, tachometer, or encoder sensing. In addition, a number of filters and settings accommodate star or delta wound motors operating with voltages from 12V to 240V in a variety of control topologies. Available with several flash memory densities and a wide range of package choices, prices for the ST7MC family range from $2.87 to $4.35 each/10,000. STMICROELECTRONICS INC., Lexington, MA. (781) 861-2650.