The present description relates to a comparator (2) comprising a ring of gates (110A, 110B, 110A′, 110B′, 106, 108) in series, wherein: each gate implements an inverting function between a first input (100) and an output (102) of the gate; at least one (110A′, 110B′) gate is controllable and is associated with another gate; each controllable gate (110A′, 110B′) comprises a control input (116) coupled with the output (102) of said associated gate, and prevents switching of its output (102) to a high state if its control input (116) is in the high state, and to a low state otherwise; and the control input (116) of each controllable gate (110A′, 110B′) receives the output (102) of said associated gate if an even number of gates separates these two gates, and receives the complement of said output if not.