Reference voltage source for low temperature coefficient with gap

Abstract

The band-gap reference voltage (RV) source with low temperature coefficient (TC) includes PTAT current generation circuit, start circuit of RV, combiner circuit of RV, neutralization circuit of base current, mirror circuit of first current. The band-gap RV source with low TC also includes generation circuit of second order temperature compensation current, which is connected to the mirror circuit of first current, and the combiner circuit of RV. Through square relation between drain-source current and grid-source voltage drop of MOS tube, inputting PTAT current and band-gap RV generates second order compensation current. The second order compensation current is output to the combiner circuit of RV to generate second order compensation voltage to compensate second order TC of RV so as to produce RV with very low TC. The invention overcomes issue of TC on the high side in traditional band-gap RV. Using standard CMOS technique realizes band-gap RV with very low TC.

Description

【Technical field】 [0001] The invention relates to the technical fields of power supply and microelectronics, in particular to a low temperature coefficient bandgap reference voltage source. 【Background technique】 [0002] In the design of analog and analog-digital mixed-signal chips, it is often necessary to generate a reference voltage with a low temperature coefficient inside the chip. This reference voltage can be provided to the inside or outside of the chip as a reference voltage to generate various required voltages. Using a reference voltage chip or other circuits It can be used to complete analog-to-digital conversion, digital-to-analog conversion, various working voltage sources, etc. [0003] Especially in some application fields with high precision requirements and good temperature characteristics, a reference voltage source with extremely low temperature coefficient is often very necessary, even absolutely necessary. [0004] For example, in the application fiel...

AI Technical Summary

Problems solved by technology

[0031] 1. The influence of the offset voltage of the comparison circuit on the selection of the reference voltage

Generally, in the CMOS process, the offset voltage of the comparator will reach 20-50mV. With such a large offset voltage, a relatively high-precision reference voltage is a fatal problem.

[0032] 2. When the voltages of VBG1 and VBG2 are very close, the comparator will not be able to determine which reference voltage to output, which may easily cause misoperation

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