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US 2008/0074159 A1Published application
Delay Circuit
AssigneeQimonda AG
InventorsPatrick Heyne, Per Johansson
Life of this patent
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Abstract
A delay circuit includes a delay device, to which an input signal is supplied. A first phase-shifted signal can be generated by the delay device, which is delayed by a first delay time with respect to the input signal, and a second phase-shifted signal can be generated, which is delayed by a second delay time with respect to the input signal. The delay device is configured such that the first and second phase-shifted signal can be generated in inverted fashion with respect to one another at an output terminal of the delay device after a delay of the input signal by a delay time.
Claims18
A delay circuit, comprising:
- a controllable delay device configured to generate first and second signals that are phase-shifted with respect to an input signal of the delay device;
- a feedback circuit configured to generate a feedback signal that is phase-shifted with respect to one of the first or second phase-shifted signals selectively supplied to the feedback circuit;
- a first phase comparison device configured to perform a phase comparison of the input signal of the delay device and the feedback signal;
- and
- a control circuit configured to set first and second delay times by which the controllable delay device respectively delays the first and second phase-shifted signals, the first and second delay times depending on the phase comparison performed by the first phase comparison device;
- wherein the controllable delay device is configured to generate the first and second phase-shifted signals in inverted fashion with respect to one another at respective first and second output terminals of the controllable delay device after a delay of the input signal by a delay time.
3 more elements
A method of operating a delay circuit, the method comprising:
- applying an input signal with a first frequency to an input terminal of a controllable delay device of the delay circuit;
- generating a first signal that is phase-shifted with respect to the input signal by delaying the input signal in the controllable delay device by a first delay time;
- and
- generating a second signal that is phase-shifted with respect to the input signal by delaying the input signal in the controllable delay device by a second delay time, wherein a level of the first phase-shifted signal generated via the controllable delay device is outputted in inverted fashion with respect to a level of the second phase-shifted signal;
- generating a feedback signal via a feedback circuit in response to receiving the first phase-shifted signal, wherein the feedback signal is delayed by a further delay time with respect to the first phase-shifted signal;
- comparing a phase of the input signal with a phase of the feedback signal;
- varying the first delay time until a phase difference between the feedback signal and the first phase-shifted signal corresponds to an integral multiple of a period duration of the input signal or until the first phase-shifted signal is delayed by a delay time with respect to the input signal;
- generating the feedback signal via the feedback circuit in response to receiving the second phase-shifted signal;
- comparing a phase of the input signal with a phase of the feedback signal;
- varying the second delay time until a phase difference between the feedback signal and the second phase-shifted signal corresponds to an integral multiple of a period duration of the input signal or until the second phase-shifted signal is delayed by a delay time with respect to the input signal;
- and
- selectively feeding the first or second phase-shifted signal to an output terminal of the delay circuit, wherein the first phase-shifted signal is supplied to the output terminal if the first delay time is less than the second delay time and the second phase-shifted signal is supplied to the output terminal of the delay circuit if the second delay time is less than the first delay time.
9 more elements
Dependencies are inferred from the claim text.