Patent ID: 6470060
Filing Date: 2002-10-22
Classification: G11C,H03D,H03K,H03L

Abstract:
A phase detector for providing a control signal according to the phase relationship between a first and second clock signal, the phase detector comprising:a first phase detector circuit having first and second input terminals coupled to receive the first and second clock signals, respectively, and an output terminal, the first phase detector circuit producing a first select signal having a duty cycle according to the phase relationship between a first clock edge of the respective clock signals; a second phase detector circuit having first and second input terminals coupled to receive the first and second clock signals, respectively, and an output terminal, the second phase detector circuit producing a second select signal having a duty cycle according to the phase relationship between a second clock edge of the respective clock signals; and a charge pump having first and second input terminals coupled to the output terminals of the first and second phase detector, the charge pump producing a non-varying control signal responsive to a first combination of logic levels of the first and second select signals, an increasing control signal responsive to a second combination of logic levels of the first and second select signals, and a decreasing control signal responsive to a third combination of logic levels of the first and second select signals.