Design Of A Monolithic Integrated Circuit For Driving Ultrasonic Motor

With the continuous development of wearable devices,robots,and electric vehicle industries,ultrasonic motors,as a new type of micro-motor,with advantages such as being free from electromagnetic interference,large output torque,fast response,and selflocking of power failure,are used more and more widely.With the development of ultrasonic motor materials and manufacturing processes,ultrasonic motors themselves have a compact structure.However,the drive voltage of ultrasonic motor is generally high,which requires the transformer,and the miniaturization of the ultrasonic motor drive circuit is difficult.With the continuous development of high-voltage integrated circuit technology and motor manufacturing technology,it is possible to miniaturize the ultrasonic motor drive circuit.By referring to some materials,the advantages and disadvantages of the current use of several drive circuit topology is comparative analyzed in this thesis.Finally this thesis determine the topology consisting of Boost converter and half-bridge inverter as the ultrasonic motor drive circuit.The circuit of this thesis is based on the 0.35?m 60 V BCD process.In this thesis,the peak current mode controlled Boost converter is used to provide power for the half-bridge inverter.Firstly,the working principle of Boost circuit and two kinds of steady-state working methods are introduced.Then,the small-signal modeling of Boost circuit is performed.The purpose of modeling is to compensate the frequency of this nonlinear system.Then the design and simulation of some key sub-modules in the Boost circuit are introduced.Half-bridge inverter with the input low-voltage two phase difference of 90 °square wave signals,makes Boost output voltage inversed high-pressure square wave signal to drive the ultrasonic motor.The half-bridge in this thesis adopts two built-in NMOS tube and uses a bootstrap capacitor to drive the structure.The dead-time of the half-bridge and the dv/dt problem caused by the rapid change of the output point voltage are considered.Then two half-bridge structures are given.A fast flip level shift circuit with two latches and a fixed dead time generation circuit are introduced.Finally,the function of the halfbridge inverter is verified by giving its transient simulation results.Finally,the overall chip simulation results,layout design and design chip test structure are given,and the overall function is tested and verified.