Based Pwm Control H-bridge Power Driver Design

In this thesis, the design of an H-Bridge Power Driver based on PWM controlis demonstrated, which used for DC or stepper motor driver. As one of typical SmartPower IC(SPIC), this device is built using a multi-technology process named BCDwhich combines bipolar and CMOS control circuitry with DMOS power devices onthe same monolithic chip. With on-resistance of 0.3? per switch,this device candeliver up to 2A continuous output current, and operate at supply voltages up to 35V.The emergence of SPIC shows a great significance to the increase of reliability, thedecrease of cost, weight and volume, and to the realization of miniaturization,intelligence in motor, industry and communication field.In this paper, the total design is firstly implemented from the viewpoint ofsystem to determine the functional modules needed and the connection betweendifferent ones. Secondly, based on the electrical characteristic requirement, design andanalysis of charge pump circuit, bootstrap circuit, thermal protection circuit, currentsensing circuit and velocity feedback application circuit are accomplished. Amongthem, the mathematic induction analysis of charge pump rise time, differentialanalysis of bootstrap rise time and bistable thermal protection circuit are theinnovative ideas in this thesis. Finally, using EDA software, the simulations of totaland sub-circuits on the basis of existed models are carried out to verify the wholedesign process.The mathematic induction is used to determine the rise time of charge pump, andthus the minimum internal charge pump capacitor is given. The differential analysis isemployed to minimize the rise time of bootstrap circuit. Namely, a few differentialequations are given firstly to describe the positive feedback rising process, secondly,rise time can be given by solving the differential equations, finally, the analysis ofmonotonicity based on second-order derivative is carried out to determine theminimum external bootstrap capacitor, and thus the shortest rise time can be obtained.A bistable thermal protection circuit is proposed in this dissertation, the positivefeedback is introduced by means of bistable state to realize the hysteresis, therefore, aconsiderable improvement in the transition speed is obtained. The proposed thermalprotection circuit generates warning and shutoff signals in 145℃and 170℃,respectively, and the transition speed can be controlled less than 2℃, and a hysteresisof 10℃can be obtained.