Analysis Of Temperature Characteristics And Design Of CMOS Bandgap Reference Voltage Source

The reference voltage source is an important unit in the integrated circuit and it is widely used in A/D, D/A, the power management integrated circuit and other circuits. Temperature characteristics are treated as the key factors affecting the performance of the reference voltage source, The the output voltage of the reference voltage source is changed by the change of temperature and the system performance of the system circuit will be influenced. With the development of technology, more and more attention is given to CMOS bandgap reference voltage source. Therefore, the research on the temperature characteristics of CMOS bandgap reference voltage source circuit has theoretical significance and engineering application value.The basic theory of reference voltage source and the basic principles of the typical CMOS bandgap reference voltage source is analyzed, based on the temperature characteristics expression of the typical CMOS bandgap reference voltage source output voltage, the relationship between the output voltage and temperatur is researched, the output voltage is mainly affected by higher-order terms.The program of a reference voltage source to compensate for higher-order terms is proposed based on the temperature characteristic expression of VBE. Accordingly, The compensation circuit of the CMOS bandgap voltage is designed. The output voltage temperature characteristic expression of the improved circuit is deduced by researching the compensation circuit. Combined with 0.35?m CMOS process model file, the device parameters of the typical CMOS bandgap reference voltage source circuit and the improved CMOS bandgap reference voltage source circuit is designed according to the VBE temperature characteristics and temperature coefficient curve.The simulation of CMOS bandgap reference voltage source circuit based on CMOS process model is made by using Spectre simulation tools to verify the feasibility of the designed circuit. The simulation results: in the temperature range of-40? ~ + 125?, the output voltage temperature coefficient of the improved CMOS bandgap reference is 0.298ppm/?. The output voltage temperature coefficient of the improved CMOS bandgap reference is obviously increased. The correctness of theoretical analysis and the feasibility of the designed circuit were verified.