Low temperature drift band-gap reference voltage source based on VBE linearization

Abstract

The invention discloses a low temperature drift band-gap reference voltage source based on VBE linearization. Circuits comprise a PTAT current generation circuit, a high-order compensation band-gap reference circuit, a first starting circuit and a second starting circuit. The reference circuit builds a nonlinear term through the difference between two VBEs with different collector current temperature characteristics, then is overlaid with the VBEs to counteract the nonlinear term, and achieves the high-order compensation effect. The collector current of the zero temperature characteristic is formed by overlaying the two VBEs, subtracting voltage of one VBE and adding on the negative temperature coefficient current generated at two ends of a resistor R3 and the positive temperature coefficient current of delta VBE generated on a resistor R1, the temperature characteristic is not affected by output voltage precision, and the high-order compensation precision is ensured. Compared with a traditional VBE linearization method, the circuits adopt the voltage-mode output VREF, influence of current mirror mismatching and output resistor temperature characteristics on compensation precision is avoided, and therefore the reference voltage of the high precision and zero temperature coefficient is obtained, and the problems of low conversion precision and the like are solved.

Description

technical field [0001] The invention relates to the technical field of analog circuits, in particular to a low-temperature drift bandgap reference voltage source based on VBE linearization. Background technique [0002] The bandgap reference source is the most widely used reference source in modern large-scale integrated circuits, and is widely used in data conversion systems, power management systems, and memory systems. The basic principle is to use a voltage with a negative temperature coefficient (usually VBE, which refers to the voltage difference between the base B and the emitter E of the transistor) and a voltage with a positive temperature coefficient (usually △VBE, which refers to the difference between the two VBE difference) are superimposed so that their positive and negative temperature coefficients cancel each other out, thereby achieving a low temperature coefficient voltage. [0003] With the improvement of system accuracy requirements, the temperature coef...

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Problems solved by technology

Exponential temperature compensation uses the law that the current gain β of the triode changes exponentially with the temperature to compensate the reference voltage. The disadvantage is that the range of β variation in practice limits the compensation effect. In addition, the power supply voltage requirement is relatively high, generally at 5V; The VBE linearization method uses the nonlinear voltage component generated by the superposition of two VBEs with different collector current temperature characteristics to offset the nonlinear term in the VBE. The disadvantage is that the circuit has high requirements for the accuracy of the resistance ratio, and the output resistance of the output branch Temperature coefficient, etc. will affect the accuracy of high-order compensation; piecewise linear compensation divides the entire temperature range into several segments, and in each small segment, the offset of the reference voltage with temperature will be greatly reduced. The more segments are divided, the offset The smaller the amount, the voltage accuracy in the entire temperature range can be effectively improved. The disadvantage is that the structure of the compensation circuit is complex, which increases the area and power consumption of the chip; the resistance method of different materials uses two kinds of resistance with different temperature coefficients as the secondary temperature Compensation, its disadvantage is that it is greatly affected by the process, and an additional layer of resistive mask also increases the design cost

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