The Design Of A42V Smart Power DC Servo Motor Driver Chip

With the appearance and development of smart power integrated circuit, the goalof integrating power transmission circuit and controlling circuit on one chip comes true.It makes the power transmission system become more and more intelligent andminiaturization. As a typical implication of SPIC, dc servo motor driver circuit iswidely used in the area of industry control, automotive electronics, aeronautics andastronautics, and consumer electronics. So it has a great meaning to research themonolithic integration of smart power dc servo motor driver circuit.A42V smart power dc servo motor driver circuit is designed in this dissertation.The chip operates from11V to35V supply voltage and delivers up to2A continuousoutput current. In this chip, power LDMOS, controlling circuit, driver circuit, protectioncircuit and current sense circuit are integrated together, which makes it as a monolithicpower system with complete function.The design of H bridge structure and two different kinds of working mode arebased on the theories of PWM control and dc motor drive mode. Some key parts in theprocess of chip design are also elaborated. Based on the first test result of this project,voltage reference, relaxation oscillator and charge-pump circuits which have someperformance deficiencies are analyzed and optimized, a high performance under-voltagelockout circuit with function of hysteresis and a stable frequency relaxation oscillatorwhich uses a single comparator and a new current pulse potential reset structure arepresented. Then the whole circuit and protection circuit are simulated through EDAtools. Finally layout design, package and testing result are given.This dissertation describes the whole process of development, which includescircuit principles, simulation practice, layout and testing, the simulation and testingresults proved the function of the chip.