Design Of Low-power Bandgap Reference With Adjustable Output

The bandgap reference is an important module in integrated circuits,and has applications in various digital-analog hybrid circuits.The research of the bandgap reference has always been the focus of circuit design.For the traditional bandgap reference voltage source,the power supply voltage requirements are relatively high.As the scale of integrated circuits increases,the feature size and integration are developing rapidly,and the heat dissipation problem of the chip becomes not negligible.For different chips,the required supply voltage is different,and the performance requirements for the bandgap reference become higher and higherThe first chapter of this paper introduces the research background of the bandgap benchmark and the research status at home and abroad.The second chapter introduces the working principle of the traditional reference voltage source,focuses on the analysis of the bandgap reference circuit,derives its output voltage,and lists a bandgap reference circuit with adjustable output.The output voltage can be adjusted by changing the value of the load resistance.Chapter 3 details the design of the bandgap reference voltage source with adjustable output.Using MOS transistors in the sub-threshold region instead of bipolar transistors,a circuit that uses the negative temperature characteristics of the gate-source voltage of the MOS transistor to generate a negative temperature coefficient voltage and uses the difference between the gate-source voltages of two MOS transistors to generate a positive temperature coefficient is proposed,and the temperature coefficient and output voltage of the circuit are calculated in detail.The output voltage of the two is summed through the circuit series,and the temperature coefficient is adjusted by adjusting the size of the MOS tube in the two circuits,so as to obtain a output voltage independent of temperature.Then the equivalent resistance of the MOS tube working in the variable resistance area is converted into current,and the output load equivalent resistance is changed by the external control signal to control the closing of the switch to achieve the purpose of adjusting the size of the reference voltage.The circuit outputs two output voltage values of 0.76 V and 0.38 V through the output adjustment circuit.Chapter 4simulates the performance parameters of the circuit and draws the layout of the circuit,and conducts post-simulation to it.The circuit designed in this paper is based on the tsmc 180 nm process design,the circuit uses MOS tube,does not use resistors and bipolar transistors.Simulation under virtuoso,the simulation results show that the output adjustable bandgap reference designed in this paper can output a reference voltage of 760 m V when the power supply is 1.2V,and the output voltage value can be changed through the output adjustment circuit.In the temperature range of-20? to 80?,TC is 41.5ppm/?,PSRR is-63 d B at low frequency,output noise is 4.52(?) when the frequency is 100 Hz,and the power consumption is only 52.8n W.The circuit layout is designed according to the layout design rules,and its performance parameters are post-simulated and compared with the corresponding pre-simulation results.The key performance parameters meet the basic requirements of a low-power bandgap reference voltage source.