Stepper-motor controller requires no external current-sense resistors

May 09, 2017 // By Julien Happich
Toshiba Electronics Europe has begun sampling a new 40V/3.0A stepper-motor control IC that requires no external current-sense resistors, and hence enables more economical and compact drives while increasing efficiency and reducing heat generation.

The company’s Advanced Current Detection System (ACDS), integrated in the 5x5mm TB67S508FTG stepper-motor controller, performs on-chip current sensing thereby saving component costs and about 66% of the board real-estate used by a typical 7x7mm control IC with external resistors. ACDS also eliminates the effects of resistor-tolerance errors, ensuring greater accuracy (+/-5%) and uniformity.

In addition, the built-in power stage leverages the latest DMOS technology to boost energy efficiency, which aids space-saving design and eases thermal management by reducing internal heat generation. The transistors of the output bridge have very low on-resistance (RDS (ON) of 0.45Ω typical, high-side + low-side).

Moreover, Toshiba’s Advanced Dynamic Mixed Decay (ADMD) mode, which controls current more closely than conventional mixed-decay modes, ensures smooth and quiet movement over a wider speed range by maintaining accurate step control up to high speeds.

The TB67S508FTG for 2-phase bipolar stepper-motor applications supports full-, half- and quarter-step resolution modes, and is delivered in a space-saving QFN36 package optimised for high heat-radiation to allow superior reliability. All the usual protection features are built-in, including thermal shutdown, over current detection, low-power and under-voltage detection, and terminal-component open/short-circuit detection (OSCM).

Toshiba Electronics Europe -  www.toshiba.semicon-storage.com