Direct-current offset automatic calibration circuit for high-speed and high-bandwidth comparator

Abstract

The invention belongs to the field of direct-current voltage offset calibration, and particularly relates to a direct-current offset automatic calibration circuit for a high-speed and high-bandwidth comparator, which comprises a first short-circuit switch, a second short-circuit switch, a comparator, a calibration logic circuit and a grid voltage generation circuit, the first short-circuit switch is connected with the positive electrode of the comparator; the second short-circuit switch is connected with the negative electrode of the comparator; the output end of the comparator is connected with the input end of the calibration logic circuit; the output end of the calibration logic circuit is connected with the input end of the grid voltage generation circuit, and the output end of the grid voltage generation circuit is connected to the comparator to form a direct current imbalance automatic calibration circuit; and a pair of MOS (Metal Oxide Semiconductor) transistors are connected in parallel to an input differential pair of the regenerative latch as voltage-controlled active resistors, and the gate end voltages of the MOS transistors are changed, so that the direct-current offset calibration of the comparator is realized.

Description

technical field [0001] The invention belongs to the field of DC voltage offset calibration, in particular to a DC offset automatic calibration circuit for a high-speed and high-bandwidth comparator. Background technique [0002] The dynamic comparator has the advantages of fast response speed and low power consumption, but because it is generally a pseudo-differential structure, it is more sensitive to device mismatch and has a larger DC offset. Therefore, there is generally a pre-amplifier in front of the dynamic comparator to suppress the DC The offset also has the function of isolating the kickback noise. A pre-amplifier with higher gain can effectively control the DC offset of the dynamic comparator to a very low level, but in the case where the additional phase shift of the comparator is required, it is necessary to achieve high gain while achieving low phase shift, the pre-amplifier The power consumption will be relatively high, and it is not suitable for applications...

AI Technical Summary

Problems solved by technology

This method needs to add considerable parasitic capacitance at the output of the preamplifier, thereby reducing the bandwidth of the preamplifier and affecting the phase shift characteristics of the preamplifier

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