RC lattice delay
AssigneeAnalog Devices Global
InventorsYunzhi Dong, Victor Kozlov, Wenhua W. Yang, Trevor Clifford Caldwell, Hajime Shibata
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Abstract
An integrated constant time delay circuit utilized in continuous-time (CT) analog-to-digital converters (ADCs) can be implemented with an RC lattice structure to provide, e.g., a passive all-pass lattice filter. Additional poles created by decoupling capacitors can be used to provide a low-pass filtering effect in some embodiments. A Resistor-Capacitor “RC” lattice structure can be an alternative to a constant-resistance Inductor-Capacitor “LC” lattice implementation. ADC architectures benefit from the RC implementation, due to its ease of impedance scaling and smaller area.
Claims20
A continuous time delay line for a residual producing circuit, the continuous time delay line comprising:
- a resistor-capacitor (RC) lattice for delaying a differential analog input pair, the RC lattice having first and second resistive components and first and second capacitive components, the first and second resistive components being cross coupled with respect to the first and second capacitive components;
- wherein the delayed differential analog input pair and a filtered version of the differential analog input pair are used to generate a residual signal, and parameters of the RC lattice correspond to a phase component of a circuit path producing the filtered version of the differential analog input pair.
A residue producing circuit comprising:
- a continuous time delay line to receive an analog input, said continuous time delay line having a resistor-capacitor lattice circuit;
- an analog-to-digital converter for converting the analog input to a digital signal;
- a digital-to-analog converter for generating a reconstructed analog signal based on the digital signal;
- and
- a node for combining the analog input and the reconstructed analog signal to generate a residue signal;
- wherein the continuous time delay line matches a phase component of the analog-to-digital converter and the digital-to-analog converter.
A method for generating a residue signal, the method comprising:
- processing an analog signal by a signal path to generate a filtered analog signal, wherein the processing comprises converting an analog signal into a digital signal, and converting, by a digital-to-analog converter, the digital signal into a filtered analog signal;
- generating a delayed analog signal based on the analog signal by a continuous time delay line having a resistor-capacitor (RC) lattice structure, wherein the continuous time delay line matches a phase component of the signal path;
- and
- producing a residual signal based on the delayed analog signal and the filtered analog signal.
Dependencies are inferred from the claim text.