Patent ID: 8493096

Claim:
A method for performing a tri-state comparison of two input signals in a window comparator circuit, wherein the method consists in a first phase: to store the voltage of a first input signal on a first capacitor, and a ground voltage on a second capacitor; to store an offset voltage on a third capacitor, and the voltage of a second input signal on a fourth capacitor; to compare in a comparator the first input voltage, which is adapted by a first factor, with the second input voltage, which is adapted by a second factor, added to the offset voltage, which is adapted by a third factor, to provide a first output signal, and wherein the method consists in a second phase: to store the voltage of the first input signal on the first capacitor, and the offset voltage on the second capacitor; to store the ground voltage on the third capacitor, and the voltage of the second input signal on the fourth capacitor; to compare in the comparator the first input voltage, which is adapted by the first factor, added to the offset voltage, which is adapted by a fourth factor, with the second input voltage, which is adapted by the second factor, to provide a second output signal, and to control the state of the first and second output signals to determine if the comparison of the first and second input signals is in a low state or in a high state if the first and second output signals have a same low or high output level, or in an intermediate state if the first and second output signals have a different output level.