Delta sigma modulator with output controlled feedback current
AssigneeNXP B.V.
InventorJan Daniël van der Klooster
Life of this patent
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Abstract
A delta sigma modulator includes a comparator circuit with an output that provides a digital signal which is indicative of a voltage of an a signal received at its input terminal. The modulator includes a continuous-time path from the modular input terminal to an input terminal of a comparator of the comparator circuit. The modulator includes a first feedback loop connected to a first integrating node of the path that provides a first comparator circuit output controlled feedback current and a second a second feedback loop that provides a second comparator circuit output controlled feedback current to a second integrating node of the path that is connected to the input terminal of the comparator and connected to a capacitor.
Claims20
A delta sigma modulator circuit, comprising:
- a circuit input terminal, configured to receive a first input signal;
- a comparator circuit including a comparator, the comparator including a first input terminal coupled to the circuit input terminal by a continuous-time path, the comparator circuit including an output to provide a digital signal indicative of a voltage of the first input signal;
- a first integrating node in the continuous-time path;
- a first feedback loop connected to the first integrating node and configured to provide a first feedback current to the first integrating node, the first feedback current is characterized as being controlled by the output of the comparator circuit;
- a second integrating node in the continuous-time path and connected to the first input terminal of the comparator;
- a capacitor including a first electrode connected to the second integrating node;
- a second feedback loop connected to the second integrating node, the second feedback loop configured to provide a second feedback current to the second integrating node, the second feedback current is characterized as being controlled by the output of the comparator circuit.
A method of operating a passive delta sigma modulator, the method comprising:
- providing an input signal to a circuit input terminal of a passive delta sigma modulator circuit, the circuit input terminal is coupled in a continuous-time path to an input terminal of a comparator of a comparator circuit of the passive delta sigma modulator circuit;
- providing a first feedback current by a first feedback loop to a first integrating node of the continuous-time path, the first feedback current is characterized as being controlled by an output of the comparator circuit;
- providing a second feedback current by a second feedback loop to a second integrating node of the continuous-time path, the second feedback current is characterized as being controlled by the output of the comparator circuit, the second integrating node is connected to the input terminal of the comparator and to an electrode of a capacitor;
- providing at the output of the comparator circuit, a digital signal indicative of a voltage of the input signal.
Dependencies are inferred from the claim text.