Circuit and method for trimming band-gap reference

Abstract

The invention relates to a circuit for trimming a band-gap reference. The circuit comprises a plurality of first trimming resistors, a plurality of first laser fuse wires, a plurality of third trimming resistors and a plurality of third laser fuse wires. The invention further comprises a method for trimming the band-gap reference. The circuit and method for trimming the band-gap reference are adopted, it is ensured that the absolute value output consistency of a reference voltage is improved, the cost of a potentiometer when a customer produces and the cost of manual calibration are saved, andat the same time, the production efficiency is improved; the absolute value of the reference voltage can be regulated either positively or negatively, at the same time, the temperature coefficient ofthe reference voltage can be adjusted bidirectionally; the problem is solved that the discreteness of the digital multimeter chip itself is invalid due to the reference voltage influenced by the process, and the yield rate is improved; the size and the cost of the chip are almost unaffected, and the circuit and method for trimming the band-gap reference has a wide application range.

Description

technical field [0001] The invention relates to the technical field of digital multimeters, in particular to the technical field of bandgap reference trimming, in particular to a circuit and method for trimming a bandgap reference. Background technique [0002] In the field of digital multimeters, dedicated ASIC chips will integrate a bandgap reference module to provide a reference for the digital multimeter. Therefore, the absolute value of the reference voltage and temperature drift are relatively high. The fluctuation of these two parameters will affect the digital multimeter. measurement accuracy. However, in the actual tape-out process of the chip, the reference voltage will be affected by non-ideal factors such as the tape-out process, and there will be poor consistency. Generally, the fluctuation is within ±100mV of the central value, and the ASIC chip will be judged as a defective products. In addition, in order to ensure the accuracy of each complete machine, the ...

AI Technical Summary

Problems solved by technology

[0007] 1) The reference voltage output of the existing digital multimeter is discrete, and the peripheral needs to be adjusted manually with a potentiometer, which results in high BOM and labor costs and low production efficiency; the resistance value of the potentiometer is prone to change after a long period of use, affecting the measurement accuracy

[0008] 2) The temperature drift of the reference voltage of the existing digital multimeter will affect the measurement accuracy of the whole machine

[0009] 3) If the dispersion of the reference voltage of the existing digital multimeter is too large and exceeds the adjustable range of the potentiometer, the chip will be judged as a defective product

Images