High-precision band-gap reference circuit

Abstract

The invention relates to the technical field of analog integrated circuits, in particular to a high-precision and low-power band-gap reference circuit which comprises a self-start circuit and a band-gap reference core circuit. The high-precision and low-power band-gap reference circuit has the advantages that the self-start circuit is used for preventing the band-gap reference core circuit from being unable to be normally started due to the fact that the band-gap reference core circuit is in a degenerate state when powered on; the linearity of PTAT (proportional-to-absolute temperature) currents in the band-gap reference core circuit can be improved owing to resistance matching and loop designs, offset voltages of clamping operational amplifiers can be reduced, and the output precision can be improved; power consumption can be reduced owing to optimal designs of the operational amplifiers. The invention is particularly applicable to band-gap reference circuits.

Description

technical field [0001] The invention belongs to the technical field of analog integrated circuits, in particular to a bandgap reference circuit with high precision and low power consumption. Background technique [0002] Bandgap reference circuits are one of the most common and important integrated circuit modules in analog integrated circuit design. Its function is to generate a stable voltage source as a reference voltage and supply it to other modules as a reference voltage. The requirements for the reference voltage in the integrated circuit are that the output precision is high, and the output voltage does not change with conditions such as temperature and process. It can be seen that how to ensure that the output voltage value of the bandgap reference circuit has high precision, constant size, and small characteristics with temperature changes is the key to the design of the bandgap reference circuit. [0003] The basic principle of the bandgap reference circuit is to...

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Problems solved by technology

[0004] Due to its superior performance, the bandgap reference voltage source is widely used in many circuit systems, but due to the traditional bandgap reference circuit structure such as figure 1 As shown, the PTAT current generated by the PTAT current generating circuit generates a voltage with a positive temperature coefficient on the resistor RA2, and a voltage with a negative temperature coefficient on the npn tube QN3. BE The voltage is superimposed to produce a voltage with zero temperature coefficient, which needs to satisfy the I MPA1 = I MPA2 = I MPA3 The condition that the collector currents of QN1 and QN2 are equal, but in fact these two conditions will be affected by external factors and cannot be satisfied, so this traditional structure cannot eliminate the error caused by the base current of the triode, which makes the generated PTAT There is a nonlinear error in the current, which affects the output accuracy, so that the temperature characteristics of the bandgap reference voltage source cannot achieve very good results

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