A circuit includes a plurality of series-coupled delay buffers and a plurality of logic gates. Each logic gate includes first and second inputs. The first input of each logic gate is coupled to a corresponding one of the delay buffers. The circuit also includes a plurality of flip-flops. Each flip-flop includes a data input and a data output. The data input is coupled to an output of a corresponding one of the logic gates and the data output is coupled to the second input of one of the corresponding logic gates.