Band-gap reference voltage source circuit

Abstract

The invention provides a band-gap reference voltage source circuit. The band-gap reference voltage source circuit comprises an operation amplifier, a third resistor, a first node, a second node, a sampling switch, a first capacitor, a filter, a switch combination circuit, N bipolar transistors, a second resistor, a first MOS transistor and a second MOS transistor. The first input end of the operation amplifier is connected with the second middle node, the second input end of the operation amplifier is connected with the first node through the third resistor, and the output end of the operationamplifier is grounded after passing through the sampling switch and the first capacitor in sequence. The first connecting ends of all the bipolar transistors are connected with the switch combinationcircuit, the second connecting ends of all the bipolar transistors are connected with the control ends of the bipolar transistors themselves and are grounded, and the switch combination circuit makesthe first connecting ends of all the bipolar transistors selectively connected with the first node or the second node. Compared with the prior art, the band-gap reference voltage source circuit can further improve the precision of output reference voltage.

Description

【Technical field】 [0001] The invention relates to the technical field of electronic circuits, in particular to a bandgap reference voltage source circuit. 【Background technique】 [0002] Bandgap reference voltage sources are widely used in various analog circuits. In practical applications, high-precision bandgap reference voltage sources are favored. Please refer to figure 1 As shown, it is a schematic circuit diagram of a bandgap reference voltage source in the prior art, which includes resistors R1, R2, R3, bipolar transistors PNP transistors Q1, Q2, and an operational amplifier OP. Generally, the emitter area of ​​Q1 is designed to be larger than that of Q2, for example, its ratio is K:1. In order to achieve a better matching effect in actual design, Q1 is generally designed as K PNP transistors in parallel with Q2. In one example K=4. Generally, the resistance values ​​of resistors R1 and R2 are designed to be the same, and are designed to be M times the resistance ...

AI Technical Summary

Problems solved by technology

[0003] Although Q1 is designed as K transistors in parallel with Q2, there is a mismatch between each transistor in Q1 and Q2, that is, when mass production, there will be differences between chips, and these differences will cause inaccurate VBG, And this difference will vary due to package stress effects

Even at the wafer or chip stage, VBG is adjusted accurately through trimming technology, but after packaging, due to the influence of packaging stress, there are deviations between chips

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