A Control Circuit Design Of A Full-bridge Power Driver

The development of smart power integrated circuits(SPIC)has greatly changed people's lives.As a typical SPIC,the full-bridge power driver controls the motor through external input signals to realize functions such as speed regulation,steering and braking.It is widely used in motor drive systems such as office,automation,industry and medical.This thesis designs a full-bridge power driver for motor drive,including the functions of UVP,OTP,OCP and current detection.The control circuit module in the driver becomes the main content of the thesis.The power supply range is 15V?60V,the temperature range is-40??125?,and the continuous output current up to 3A.Firstly,the author introduces the structure of the power device LDMOS in the output stage of the driver,and the relationship between the withstand voltage,on-resistance,threshold voltage and structural parameters is analyzed.After that,discusses the isolation method of high with low voltage devices in the circuit.In addition,analyzes the overall structure,working principle and two control modes of the full-bridge power driver: Signal Magnitude and Locked Anti Phase.And then,the functions and indicators of each circuit module are introduced.Finally,the chip's reference source,comparator,logic control,oscillator,over-temperature protection and overall circuit are designed and simulated.Using the PDK provided by the manufacturer,the author draws the layout of some module circuits.The design of the thesis is based on 0.35 BCD process,using the EDA tool Cadence Spectre simulator to simulate and verify the reference source,comparator,logic control,oscillator and over-temperature protection circuit modules.After that,combining with the given design indicators,co-simulate the overall circuit of the chip and verify the results.The reference source circuit adopts zener diode technology,which can realize a wide range of power output,it has good temperature characteristics in the range of-40??125?,a 12 V undervoltage lockout threshold;the comparator hysteresis is 0.45 V,its conversion rate is 1.177V/ns;the logic control circuit can realize the logic signal output of the motor state table;the oscillator output frequency is 302 KHz,with small temperature and process deviation;The over-temperature protection alarm and shutdown temperature thresholds are 146.4°C and 167.4°C,respectively,the hysteresis is 12.6°C.After the sub-module is verified,the overall simulation of the driver is carried out,and the logic signal output of the two control modes is verified,and the output current in both control modes reaches 3A.In SM mode,the output signal of the charge pump and the bootstrap voltage both reach 54 V,and the gate-source voltage of the high-side switch tube reaches 8V.The designed full-bridge power driver can achieve the preset target.