Current trimming circuit for bandgap reference

Abstract

The invention discloses a current trimming circuit for band-gap reference, relates to the technical field of integrated circuits. The current trimming circuit is connected in parallel with a source electrode and a drain electrode of a current mirror MOSFET, and comprises a plurality of groups of parallel branches, each group of branches has the same structure and comprises a switch and an MOSFET tube, a first end of the switch is connected with the source electrode of the MOSFET tube, the first ends of the switches are connected in sequence, the second ends of the switches are connected in sequence, the drains of the MOSFETs are connected in sequence, bias voltage the same as that of the grid of the current mirror MOSFET is connected to the grid of the MOSFET, the source of the current mirror MOSFET is connected with a power supply, the drains of the current mirror MOSFET are grounded through resistors, and the switches are used for adjusting trimming current of branches and further adjusting output voltage of the resistors. The area of the chip is greatly reduced by trimming the MOSFET, the trimming without frequency limitation is realized by adopting switch trimming, and the trimming numerical value is increased or decreased as required.

Description

technical field [0001] The invention relates to the technical field of integrated circuits, in particular to a current trimming circuit for a bandgap reference. Background technique [0002] The bandgap reference circuit can output a reference voltage that does not change with the power supply voltage and temperature. The sensitivity of the output reference voltage to temperature changes is an important technical parameter of the bandgap reference circuit, namely the temperature coefficient. [0003] A rationally designed bandgap reference circuit has good temperature coefficient and linearity in theory. However, due to the numerous process steps in the integrated circuit manufacturing process, errors will inevitably occur in each device used in the circuit. The accumulation of these process errors will eventually lead to the output voltage value, temperature coefficient and other parameters not meeting the design requirements. [0004] To solve this problem, trimming cir...

AI Technical Summary

Problems solved by technology

[0005] like figure 1 As shown, the traditional trimming circuit usually trims the resistors, which takes up a lot of chip area

And the traditional trimming circuit often uses fuse trimming, which makes the trimming process irreversible and can only be trimmed once

After a trimming is completed, when the output voltage parameters are unstable due to changes in the working environment and long-term use, the fuse trimming circuit cannot correct the output voltage of the circuit again

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