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Multi-function driver IC consolidates stepper and brush-DC motor controls

1st February 2008

Toshiba

ES Admin

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Toshiba Electronics Europe has announced a multi-motor driver IC with valuable integrated features, allowing engineers to establish a common hardware solution to driving multiple stepper motors or brush DC motors. The Toshiba Electronics TB62237BFG uses Toshiba’s high-voltage IC technology to combine four H-bridge outputs with motor-control logic for stepper and brush DC motors, as well as three DC-DC converters, a built-in timer and protection functions. This creates a highly integrated solution for single-, dual- and quadruple-axis motor driving duties. The DMOS motor-driver outputs achieve low on-resistance of 0.6O for low-loss operation, leading to high efficiency. A further benefit is low heat dissipation, which enhances reliability and reduces cost by easing thermal management.

With two 16-bit shift registers, each equipped with a latch, the IC is capable of driving any combination of stepper and brushed DC motors up to a maximum of four axes. Each of the four H-Bridges can be programmed to accommodate either a stepper configuration with 4-bit micro stepping or a DC brushed one. Since parallel operation of each two H-Bridges is also supported the designer has the choice to drive fewer motor axes but with higher current. High-speed chopping at up to 150kHz is possible, controlled by an external oscillator. Motors operating at an input voltage up to 40V can be driven, and the maximum standard motor-driving current is 6.4A per bridge. This can be increased to 8.0A for single- or dual-axis operation by connecting the device’s H-bridge pairs using external jumpers.

Four selectable mixed decay schemes optimise performance for stepper motor drives. There are three independent DC/DC converters each one allowing for output currents up to 1.2A and by parallel operation of two converters a maximum of 2.4A can be realised.

Additional on-chip features include a built-in timer that starts running when the IC is supplied with power, which can be used to initialise external devices. A Reset block is also implemented on-chip, making it possible to deliver an external reset signal.

In addition, the TB62237BFG implements comprehensive protection functions to prevent damage to the motor as well as the IC without requiring external components. Protection functions include over-current and over-voltage protection for internal DC-DC converters, as well as motor over-current protection and IC over-temperature protection. The device is delivered in a 64-pin QFP surface-mount package featuring a metal plate on the bottom side which can be soldered directly to a suitable copper plane on the printed circuit board resulting in efficient cooling.