High-performance Cmos Band Gap Voltage Reference Source And Design

Voltage reference is a vital basic module which is widely adopted in analog circuits(mixed signal circuits). Its temperature stability and antinoise capability influence the precision and performance of the whole system. The main purpose of this research is to use standard CMOS process to design a high performance voltage reference, which can be adopted in a program named microsilicon capacitive accelerometer monolithic measurement circuits.In this paper the present situation and developmental trend of voltage reference studies both at home and abroad will be presented, the performance index of voltage reference will be introduced, and also the principle of bandgap voltage reference will be analyzed. By comparing and analyzing the advantages and disadvantages of three kinds of voltage reference circuits,type of current density ratio compensation,weak inversion type and type of poly gate work function, a cascode structure of type of current density ratio compensation is chosen to form the core of voltage reference circuit designed in this paper. Applying the negative feedback technology, an output buffer and multiply by-2-circuits are designed, which improve the current driving capability. The circuit design of bandgap voltage reference is completed,considering the high order temperature compensation with real resistors. The circuits designed have been simulated, using csmc 0.6um CMOS parameter files. Also, a layout of the whole circuits is designed based on the design rule file. At last, the layout is verified with Cadence verification tools, Dracula. DRC(Design Rule Cherker) and LVS(Layout Versus Schematic) have been done successfully, which improve the feasibility of the layout design. So the whole IC design flow, from the front end to the back end of a circuit design, is completed.The simulation results show that, at room temperature(27℃), the voltage reference designed in this research provides 1.24994v and 2.50048v output voltages, which fulfil the requirements of 1.25v and 2.5v output voltage; at the temperature range of–40℃to 85℃, the temperature coefficient of output voltage 1.24994v is about 17.8ppm/℃. As the process corners vary, the power consumption is 1.94mW at most and 1.13mW at least, under the condition of 5v power supply. In the frequency range of 1Hz to 600MHz, the worst power supply rejection ratio (PSRR) is about–20.7dB. The whole circuit design fulfils the requirements of the program mentioned above.