Fully integrated ultrasonic motor speed control system with fine output frequency resolution, power stage and digital controller

This paper deals with an ultrasonic motor driver IC; a complete speed control system is realised inside the device using smart power IC concept, that is chip including power stages as well as analog and digital signal handling. This kind of chips can only be realised using mixed technology including bipolars, CMOS and DMOS components. The circuit includes double full power bridge as final actuators for the motor, digital feedback coming from the motor through optical encoder signals, digital motor speed controller. The motor driving is realised through a frequency; system requirements in terms of frequency generation are very strict and the output period must be generated with steps of about 400 ps. To achieve this goal a mixed technique has been used.