Band-gap reference voltage circuit

Abstract

The invention discloses a band-gap reference voltage circuit. A current source is additionally arranged, a reference voltage output end and a power source end are arranged, density of current flowing through a second triode is n times of the density of current flowing through a first triode in a micro current source unit, a power supply end of a difference amplifier unit is connected with the power source end, a collector of a third triode is connected with the power source end through the current source, an emitting electrode of the third triode is connected with an input end of the micro current source unit, the collector of the third triode is connected with an output end of the difference amplifier, and a connecting point and a base electrode of the third triode are both connected to a reference standard output end. As an implementation mode of the micro current source unit, resistance value of a third resistor is n times of that of a second resistor, and the first triode is symmetrically matched with the second triode. The band-gap reference voltage circuit is high in accuracy, low in power source noise, small in temperature coefficient, low in power, capable of directly generating reference voltage over 1.25V, needless of being connected with a peripheral resistor for working and suitable for generating reference voltage inside a chip.

Description

technical field [0001] The invention relates to a bandgap reference voltage circuit. Background technique [0002] The so-called reference voltage refers to a DC voltage that has nothing to do with the power supply and process and has definite temperature characteristics. In integrated circuits, the design of reference voltage is an indispensable and important part, and the design of reference generation in CMOS technology is widely recognized as "bandgap" reference voltage. A reference voltage independent of power supply, process, and temperature is essential in many designs to provide an accurate judgment standard or bias voltage for the chip. To generate a zero temperature coefficient voltage, one needs to add a positive temperature coefficient and a negative temperature coefficient voltage in the proper ratio. Among the various device parameters of the semiconductor process, since the characteristics of the bipolar transistor have the best repeatability, the base-emitt...

AI Technical Summary

Problems solved by technology

Inside the chip if according to Figure 4 Make connections, and use the internal power supply of the chip to supply power to TL431. In order to make the voltage input relatively small and provide enough current, the value of resistor R3 is relatively small; but if the input becomes larger, there must be a large current through resistor R3, for example, input=5V, Vref=2.5V, take R3=10K, then the current through R3 is (5V-2.5V) / 10k=250uA; if the input rises to 20V, then the current through R3 is (20V-2.5V) / 10K=1750uA, then the power consumption of TL431 is very large or even unusable. At the same time, the power supply rejection ratio is very small through the resistor R3, that is, the change signal of the power input is easily transmitted to TL431, causing its output reference voltage to change accordingly. , therefore, TL431 is not suitable for generating the internal reference voltage of the chip

Images