Method and device for phase detection

Abstract

A phase detection system is used in particular in a Delay-Locked Loop (DLL) to generate, as a function of phase differences of different signals (1, 2, 3), at least one control signal for changing the phase delay of phase delay elements (8, 9) in order to obtain a defined phase delay between the signals (1, 2, 3). For this purpose, an up signal for increasing the phase delay and a down signal for reducing the phase delay are advantageously generated, both of which signals act on a charge pump (21) the output signal of which can be used to control the phase delay elements (8, 9). To be able to control even very small phase differences, the up signal and the down signal are generated in such a way that in the steady oscillating state they simultaneously adopt their active switching state for a certain duration during each period. To obtain good control performance of the phase delay of the two phase delay elements (8, 9), in particular even at high frequencies, the up signal and the down signal are generated according to the invention in such a way that in the steady oscillating state, i.e. when the phase delay of both phase delay elements (8, 9) corresponds to the reference phase delay, they each adopt their active switching state for at least one-quarter of the period duration of an input signal (1). The up signal and the down signal are preferably generated by a circuit arrangement of logic gates (10-19, 22-32).

Dependencies are inferred from the claim text.