Design Of SiC Bipolar Transistor Linear Regulator

Since the beginning of the 21st century,some new extreme application environments have appeared,and some extreme environments have high requirements for temperature,making it difficult for traditional silicon-based integrated circuits to meet the requirements of these environments.As the third-generation wide-bandgap semiconductor material,SiC has a relatively large band gap and better thermal conductivity,which makes more and more researches pay attention to the use of SiC materials to make integrated circuits to meet the needs of high-temperature environments.The high-temperature SiC BJT integrated circuit design also faces challenges such as temperature compensation and process technology of each sub-circuit module.Therefore,in order to solve this problem,this paper uses software simulation to design the SiC BJT linear regulator.The temperature characteristics of SiC integrated resistors made of different thin film layers are studied,analyzed the temperature dependence of each sub-module circuit in the SiC linear regulator,and based on the analysis of the temperature characteristics of the sub-module,the design of the linear regulator is completed.Finally,the process technology of SiC integrated circuit is researched,and the layout design of SiC BJT linear regulator is completed.The main research content and results are as follows:1.The temperature characteristics of SiC integrated resistors are studied.The temperature characteristics of integrated resistors made of different thin film layers were studied,the results show that the sheet resistance of the resistor made with the n-type highly doped collector layer increases with the increase of temperature;the sheet resistance of the integrated resistor made of the p-type base layer decreases with the increase of temperature,and changes greatly in the entire temperature range of 300K-773K.2.The temperature characteristics of the current mirror circuit,the error amplifier circuit,the buffer stage circuit and the feedback resistor network are studied.The simulation results show that the fluctuation variance of the output current of the proportional current mirror circuit in the entire temperature range of 300K-77K is as small as 0.01;the Darlington structure of the error amplifier module can greatly increase the current amplification gain,and can reduce the impact of the drop in the amplification factor of a single SiC NPN transistor due to temperature rise;the buffer stage circuit is implemented with an emitter follower structure,which can meet the requirements of low output impedance and high bandwidth;The proportional form of the feedback network resistance can also effectively reduce the influence of temperature changes on the sheet resistance.Using the above modules can effectively improve the temperature stability of the circuit.3.This paper designs a SiC linear voltage regulator which can work stably in a wide temperature range of 300K-773K,and simulates it in a wide temperature range of 300K-773K.The simulation results show that the output voltage of the SiC linear regulator can reach 15V and the load current can reach up to 150mA.The variation of the output voltage is less than 2%in the whole temperature range of 300K-773K.The linear adjustment varies from 33 to 46(mV/V)over the entire temperature range and the load adjustment varies from 1 to 3%over the entire temperature range.4.A manufacturing process of SiC bipolar linear regulator is proposed,then the layout of a single SiC BJT and SiC integrated resistor was designed,and completed the layout design of the SiC BJT linear regulator.