Driver ICs Detect Motor Stalls Without Sensors

Sensorless stall detection without the need for an encoder is incorporated in the TMC246 and TMC249 driver chips. Both devices can predict a motor overload, which is important in high-reliability applications. The TMC246 is a dual full-bridge driver for bipolar step motor control. Internal DACs allow for micro-stepping as well as smart current control that permits cool motor and driver operation. The IC can be controlled via serial interface (SPI) or analog/digital signals. A user can operate the device at high temperature (up to 105° C) or at high current (up to 1.5A per phase). Short-circuit, temperature, under- and over-voltage protection are built in. The TMC249 is a high-current version of the TMC246. It supports up to 75 Vdc at 10A set by external power MOSFETs. It can also be used for unipolar step motors, which requires four external PMOS transistors. LIN ENGINEERING, Santa Clara, CA. (408) 919-0200.