A 1a/35v Monolithic H-bridge Power Driver Ic Design

The emerging of smart power integrated circuit (SPIC) is important to increasethe system's reliability and reduce cost, weight and volume. It enables the design andproduction of even more miniaturized and smart systems for different applications inthe field of automotive, industrial and telecommunication. In this thesis,a 1A/35Vmonolithic H-Bridge power drive integrated circuit has been designed. It is a typicalSPIC, which could be widely used in low-voltage, large-current, mid-power DC andstepper motor drive, position and velocity servomechanism, factory automationrobots, numerical controlled machinery, printers and plotters control and applications.The design goal of the circuit is V (max) is 35V, I (max) is 3A, the highest frequencyof operation (f (max)) is 300 KHz, and the RDS (ON) of DMOS is only 0.3?. And it hasover-temperature, over-current and under-voltage lockout protection.During the circuit design, the author analyzed the basic principle of theH-Bridge power driver and designed its general structure. The current sensing is acrucial technique in SPIC. Using the typical structure of power devices (SENSEFET),a current sensing circuit based on voltage mirror is designed to realize sensing thecurrent of high-side power transistor as a ratio of 2000:1. Simply connecting aresistor between the sense out pin and ground convert this current to a voltage. Thisvoltage is then suitable for feedback to control the motor's position or velocity.The design of power device and the drive circuit's high and low voltagecompatible technology-the Bipolar-CMOS-DMOS (BCD) process technology-arevery important in SPIC. Hereby, the hex sense power mosfet and the UP-DRAINtechnology are employed. The RDS (ON) of power mosfet is detailedly analyzed andoptimization designed. Based on the BiCMOS technology, after referenced theconventional BCD technology in the world and considered the specialty of the circuit,the drive circuit's high and low voltage compatible technology is designed. Thedesign rules is given, and layout is designed and verified. At last, high-voltagedevices and drive circuits was fabricated in the first time. The measured results showthat the devices parameters are accordance with the design values.