Capacity mismatch calibrating device

Abstract

The invention discloses a capacitor mismatch adjusting device used in the chip and is composed of the capacitor to be adjusted, comparator maladjusted adjusting capacitor, adjusting capacitor and comparator. The capacitor mismatch compensating circuit of the invention adopts the charge on the self-adapting adjusting mismatch adjusting capacitor, increases the speed of the circuit, and eliminates the affect to the capacitor mismatch from the channel charge afflux and the clock feedthrough caused by the on-off of the diode. It is also benefit to increase the precision of the capacitor match.

Description

technical field [0001] The invention relates to a mismatch calibration circuit applicable to successive approximation analog-to-digital converters, pipeline structure analog converters and other mismatch calibration circuits that require precise capacitance matching, in particular to a capacitor mismatch calibration device that can be used in chips. technical background [0002] Under the existing process technology conditions, due to the random fluctuation of the process, the matching accuracy of the capacitor is about 10-11 digits. Therefore, when precise matching of capacitors is required, such as high-speed and high-precision ADCs, DACs, and switched capacitor circuits, etc., must be Capacitors are mismatch calibrated to achieve an exact match. Common capacitance mismatch calibration techniques include charge redistribution, capacitance averaging techniques, and laser correction. Although charge redistribution and capacitance averaging tech...

AI Technical Summary

Problems solved by technology

Although charge redistribution and capacitance averaging techniques can greatly reduce capacitance mismatch, these two capacitance mismatch reduction techniques require additional storage capacitance on the signal transmission path, which reduces the speed of the circuit, and it cannot eliminate Effects of Channel Charge Injection and Clock Feedthrough Caused by Transistor Switching on Capacitance Mismatch

For on-chip capacitor laser trimming, the calibration process is only performed once during chip manufacturing, which requires the circuit to have time and temperature stability, and requires additional calibration procedures, increasing costs

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