A two-in-one chip it delivers a 2-channel drive function, capable of running two stepping motors simultaneously. By integrating functions into a single chip Toshiba has been able to free up board space and to reduce device size. Heat generated by the IC itself was one of the reasons that conventional drivers could not achieve continuous operation in applications requiring drive currents in the 2.0A range. However, the TC78S122FNG can simultaneously drive two channels thanks to a low maximum on resistance of 0.6O (a reduction of 50% compared to previous products) that cuts heat generation.
In previous products the regulator circuit for the IC’s internal logic operated at standby. The new product can stop the regulator at standby due to incorporation of a ‘Sleep’ function. As a result IC power consumption has been reduced. Moreover, the TC78S122FNG not only drives the stepping motors, but also provides an interface for driving brushed DC motors. For example, this could include one-channel for the stepping motor, and two channels for running brushed DC motors.
To provide reduced vibration and noise, the TC78S122FNG offers high-resolution motor driving of ¼ steps (max.) and a decay mode switching function for constant current control. Built-in error detection features include a thermal shutdown circuit and an overcurrent shutdown circuit to provide enhanced reliability and safety.
Currently housed in a compact HTSSOP package (measuring 12.5mm x 8.1mm x 1.2mm), Toshiba is planning to introduce another version of the TC78S122FNG in an even smaller QFN package style.