Design Of Low-voltage, Low-Temperature Coefficient, High PSRR Bandgap Voltage Reference

Voltage references, as an important module in the integrated circuits (ICs), havebeen widely used in many applications, from analog circuits to digital-analog mixedsignal Integrated Circuits. Since the bandgap voltage references were invented in1980’s, they have been the most popular solution. With the development of IntegratedCircuits industry and manufactural technique of semiconductor, bandgap voltagereferences are except to have more and higher requirements so as to meet individuals’demands. Such as, low-voltage, low power waste, high power supply reject ratio(PSR), low-temperature coefficient (TC), low-line regulation.This paper mainly designs a bandgap voltage reference with low-power supply,low TC, high PSR. When the specification of a bandgap voltage reference is offered,a thorough research is gotten down to doing. And there is a proper topology whichcan met the specification. In order that the bandgap voltage reference is able to workin low power supply, current mode bandgap voltage reference is selected. A NovelHigher-Order Compensation method is introduced so that the bandgap reference haslow temperature coefficient. There is a measure to be taken to make the bandgapvoltage reference have high power supply reject ration performance. Given the outputof the bandgap reference will suffer from the load in external working environment, abuffer composed of two stage operational amplifier is inserted between the referenceoutput and the external load. At the end, trimming is introduced so as to reduce theprocess error. This paper generates some innovations:1、Calculate and simulate the PSR of the current-mode bandgap voltagereference circuit, and know about how to enhance the PSR. It is remarkable importantto ensure that the output of the operational amplifier inside the bandgap coresimultaneously changes extent and phase against the power supply. If this is to bedone, the current at the output will keep invariable. Then, the out voltage will alsoretain a given output.2、A Novel Higher-Order Compensation method is introduced so that the bandgap reference has a low temperature coefficient. The method reduces thetemperature coefficient in evidence at the express of only a little layout area.3、Given that the bandgap may appear overshoot when supply is power on, asoft-startup circuit is selected.With the Cadence tool, the SMIC0.13um EEPROM technology and devicemodel, the current-mode bandgap voltage reference is simulated. The result provesthat the circuit can work normal at1.1V power supply. The simulated temperaturecoefficient of first-order bandgap voltage reference is21.72ppm/℃within the widetemperature range of-55～125℃. Under higher-order curvature compensation, thetemperature coefficient of bandgap reference can be reduced to2.89ppm/℃, the errorof the output is0.36mV after the higher-order curvature compensation, which theresult is2.7mV before the higher-order curvature compensation. The PSR is70dB atlow frequency and53dB at5MHz. In the transient analysis, there is no overshootwhen the power supply is turned on and turned off. In a word, the bandgap voltagereference meets the design specification. The chip-test results show that most chipshave a good performance.