Research And Design Of A Dual-Channel High-Side Smart Power Switch Circuit

The high-side smart power switch integrates the high-side power FET,protection circuit,drive circuit,fault diagnostic circuit and control circuit on a single chip.It can work in harsh environments.It integrates functions such as temperature detection and current detection,and it can drive inductive,capactive and resistive loads,such as heater and electric motors.The advantages of high-side smart power switch are easy to drive,high stability,small size and low manufacturing costs,making them widely used in consumer electrics,aerospace and automotive electronics.In recent years,with the development trends of smart and miniaturized electronic equipments,and in the context of the localization of chips in our country,it is of great significance to study the high-side smart power switch.In view of our country's application requirements for high-side smart power switch in the fields of automotive electronics and military electronics,this thesis designs a dualchannel high-side smart power switch,whose channel 1 and channel 2 have a symmetrical structure and can be operated in single channel or dual channel.The high-side switch can work under a wide range of supply voltage from 7 V to 58 V,and the typical operating voltage is 24 V,the single-channel on-resistance is less than 125 m?,the dual-channel on-resistance is less than 63 m?,the operating temperature range is-40 ??150 ?,the maximum turn-on time is 50 ?s,and the maximum turn-off time is 95 ?s.At the same time,it has protection functions such as overvoltage protection,overtemperature protection,current-limiting protection,as well as open load detection and short-circuit detection.This thesis firstly analyzes the working principle of the dual-channel high-side smart power switch,introduces the overall structure and sub-module functions,gives the design goals,and clarifies the design indicators.After that,each sub-module of the chip is designed and analyzed,and the simulation is carried out.The sub-module includes the input stage circuit and the voltage regulators,the drive circuit,the protection circuit and the diagnosis circuit.The voltage regulators include the voltage regulator power supply and the floating ground rail.The drive circuit include an oscillator,a charge pump and a charge pump control circuit.The protection circuit include over voltage protection,overtemperature protection and current limiting protection.The overvoltage protection include VBB-GND overvoltage protection,VBB-OUT overvoltage protection and gate protection The diagnostic circuit include open load detection,short load detection and status feedback circuit.After that,the whole chip is simulated and verified,the key parameters of single-channel and dual-channel are simulated respectively,and the fault detection simulation of the whole chip is carried out,including open load detection,short load detection,inductive load shutdown and overtemperature protection.Combined with the given design indicators,the simulation results are analyzed.At the normal temperature of 25 ?,the chip's single-channel on-resistance is 94 m?,the dual-channel on-resistance is 47 m?,and the turn-on time is 14?s,the turn-off time is 24 ?s,and the function of the fault detection modules are correct.After simulation verification,the results meet the design specifications.Finally,the process platform of the high-side smart power switch is analyzed,the BCD process used in its manufacture is introduced,and the layout is designed.