Design Of A Bandgap Reference Voltage Source

Voltage reference and current reference is present in analog circuits.Temperature changes,the effects of different process parameters on the reference voltage and the supply is small.Stability of the circuit is directly controlled by them,not only the quality of the fundamental elements of the reference source performance electronic design,and it is backed by an electronic device,leave it electronic product will not be stable and accurate work.Therefore very important thing is to design a more accurate very stable band-gap reference voltage source,which is of great significance for the development of the whole industry.The purpose of this bandgap reference voltage source is designed to have a high load capacity,can improve the load capacity of the entire circuit,and can provide a stable output voltage.The circuit design has three main components: The first is the start-up circuit,which is mainly composed of self-biasing circuit,and its main role is to start the circuit when the circuit quickly enter the work state,which means it is a start mechanism when the circuit is turned on,the bias start-up circuit can be automatically shut down to avoid power consumption.Followed by the bandgap circuit,use the PTAT current generating a reference voltage,the first use of positive temperature coefficient PTAT current through the resistor generates a voltage positive temperature coefficient,and then adding the bipolar collective pipe,then obtain the reference temperature-independent zone gap voltage.Finally,the output circuit that a voltage proportional circuit and a driver circuit of a single follower.The first half is a voltage scaling circuit,the main function of this circuit is to determine the proper voltage,the circuit is in phase with the input circuit,it is possible to obtain different desired reference voltage value by the voltage output circuit than the column.The second half of the entire circuit is a voltage follower to drive the tube voltage follower circuit is large pipe,it can output more current,thereby increasing the load capacity of the bandgap reference circuit.This circuit can be both different required voltage reference value,but also can improve the load capacity of the entire circuit.This is also the place where the highlight of the entire circuit,generally bandgap reference voltage circuit do not have this feature added in this design this circuit,so that the function of the entire circuit is more powerful,the utilization higher.After the basic structure of the circuit design is complete,it is necessary to use cadence circuit performance simulation software,test circuits,verify the circuit meets the design requirements.We transient circuit,open-loop characteristics,closed loop characteristics,temperature drift coefficient,PSRR,CMRR,on-time performance and other parameters of the simulation,the simulation results show that the phase margin of the open loop state is 56.66 dB,common mode rejection ratio of 57.5dB,the power supply rejection ratio of 35 dB or more,within a temperature range of-40 ~ 85 ?,drift coefficient bandgap reference voltage source is about 12.7 ppm/?,input noise is 0.000414122 dB,transient simulation output waveform is no obvious distortion,resulting simulation results consistent with the design requirements.