Novel dynamic comparer capable of correcting offset voltage

Abstract

The invention discloses a novel dynamic comparer capable of correcting the offset voltage. The novel dynamic comparer comprises a preamplifier, a latch and an offset correcting circuit, wherein the preamplifier comprises a first MOS (Metal Oxide Semiconductor) transistor as a bias current source, a second MOS transistor and a third MOS transistor which are taken as differential input geminate transistors, a fourth MOS transistor and a fifth MOS transistor which are taken as load transistors as well as a sixth MOS transistor and a seventh MOS transistor which are respectively a PMOS (P-channel Metal Oxide Semiconductor) transistor respectively; a grid electrode of the sixth MOS transistor is connected with bias voltage, a source electrode of the sixth MOS transistor is connected with a drain electrode of the fourth MOS transistor, and a drain electrode of the sixth MOS transistor and a drain electrode of the second MOS transistor are connected to a first output node of the preamplifier; and a grid electrode of the seventh MOS transistor is connected with the control signal output end of the offset correcting circuit, a source electrode of the seventh MOS transistor is connected with a drain electrode of the fifth MOS transistor, and a drain electrode of the seventh MOS transistor and a drain electrode of the third MOS transistor are connected to a second output node of the preamplifier. The preamplifier of the comparer disclosed by the invention has the advantages of higher gain and higher speed; and the inserted MOS transistors are lower in load effect.

Description

technical field [0001] The invention belongs to the field of analog circuit design, in particular to a new dynamic comparator for correcting offset voltage. Background technique [0002] The dynamic comparator based on the latch has the characteristics of zero static power consumption, fast comparison speed and small area, and can be applied to integrated circuit systems requiring low power consumption and small size. However, the offset voltage of the dynamic comparator is generally high, which limits the minimum voltage that the comparator can resolve. [0003] To reduce the offset voltage of the dynamic comparator, one can use as figure 1 Comparator with offset correction circuit shown. The circuit includes 3 parts such as pre-amplifier, latch and offset correction circuit. [0004] The main circuit of the pre-amplifier includes the bias current source MN0, the differential input pair transistors MN1 and MN2, and the load transistors MP3 and MP4. The input voltages Vi...

AI Technical Summary

Problems solved by technology

A disadvantage of this offset correction method is that the additional capacitance of the MN5 and MN6 tubes will bring a load effect to the output node of the pre-amplifier

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