High-accuracy reference current source

Abstract

The invention relates to an integrated circuit technology, in particular to a low-temperature-coefficient high-accuracy reference current source. The high-accuracy reference current source is characterized by comprising a first current generation circuit, a second current generation circuit and a reference current output circuit. The first current generation circuit and the second current generation circuit are connected with the reference current output circuit. The first current generation circuit generates current in direct proportion to sigma T0.5, wherein sigma is a constant. The second current generation circuit generates a proportional to absolute temperature (PTAT) current source, and the output end of a reference current output circuit is the output end Iref of the high-accuracy reference current source. The high-accuracy reference current source has the advantages of being high in accuracy, low in temperature coefficient and suitable for reference current sources.

Description

Technical field [0001] The invention relates to integrated circuit technology, in particular to a reference current source with low temperature coefficient and high precision. Background technique [0002] In the field of integrated circuits, current reference is a very important circuit. The stability of the reference source determines the performance of the circuit to a large extent. In an extreme temperature environment, a large deviation of the reference source may directly cause the chip to work abnormally. As the scale of integrated circuits continues to expand, the performance requirements of the chip are also increased, which requires higher and higher current accuracy provided by the current reference source. [0003] An important indicator to measure a reference current source is the temperature coefficient TC, which reflects the reference current source in the entire operating temperature range [T MIN , T MAX ] The maximum value of the reference current I MAX And min...

AI Technical Summary

Problems solved by technology

[0004] Traditional benchmarking approaches such as figure 1 As shown, including PMOSI tubes M1 and M2, operational amplifiers, resistors R1 and R2, transistors Q1 and Q2, a bandgap reference voltage source Vref is generated. The principle of Vref generation is: ΔVbe with positive temperature coefficient and ΔVbe with negative temperature coefficient The Vbe is added according to a certain ratio to eliminate the first-order term of the temperature coefficient. However, due to the nonlinearity of the BJT collector current, the traditional bandgap reference only performs first-order compensation and ignores the higher-order term, which leads to a higher temperature coefficient.

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