Patent ID: 11962440
Assignee: QUALCOMM INCORPORATED
Field: Digital communication (Electrical engineering)
Classification: CPC H  G | IPC G  H

Claim 19:
20. A method of operating a comparator, the comparator including a first inverter, a second inverter cross-coupled with the first inverter, a first drive transistor coupled to the first inverter, and a second drive transistor coupled to the second inverter, wherein a gate of the second drive transistor is coupled to a first node, and a gate of the first drive transistor is coupled to a second node, further wherein the comparator further includes a first offset transistor coupled to the second node, and a second offset transistor coupled to the first node, the method comprising:
if a previous bit value is one,
comparing an input voltage with a first compare voltage using a first input circuit, the first compare voltage including a first offset-cancellation component, and
generating a first voltage on the first node and a second voltage on the second node based on the comparison of the input voltage with the first compare voltage;

if the previous bit value is zero,
comparing the input voltage with a second compare voltage using a second input circuit, the second compare signal including a second offset-cancellation component, wherein the first offset-cancellation component and the second offset-cancellation component contribute to cancellation of an offset voltage of the comparator, and
generating the first voltage on the first node and the second voltage on the second node based on the comparison of the input voltage with the second compare voltage;
using a first digital-to-analog converter (DAC) to generate a first offset-cancellation voltage;
inputting the first offset-cancellation voltage to a gate of the first offset transistor;
using a second digital-to-analog converter (DAC) to generate a second offset-cancellation voltage; and
inputting the second offset-cancelation voltage to a gate of the second offset transistor, wherein the first offset-cancellation voltage and the second offset-cancellation voltage contribute to the cancellation of the offset voltage of the comparator.