Oscillator regulation
AssigneeNordic Semiconductor ASA
InventorsHarald GARVIK, Erlend STRANDVIK
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Abstract
Provided is a method for controlling the bias current, IPIERCE, of an oscillator. The method includes acquiring or determining a digital representation encoding a bias current. The method also includes carrying out an algorithm to update the digital representation if the oscillation amplitude is measured, by one or more peak detectors, to be outside of upper and lower thresholds. Also provided is an apparatus arranged to control the bias current of an oscillator using this method, the apparatus including one or more peak detectors and a current digital to analogue converter.
Claims25
A method for controlling the bias current of an oscillator, the method comprising:
- a) acquiring a digital representation encoding a bias current;
- b) monitoring an oscillation amplitude of the oscillator at a node using one or more peak detectors;
- c) using the peak detector(s) to carry out a comparison of the oscillation amplitude at the node with an upper amplitude threshold and a lower amplitude threshold,
- d) if the comparison determines that said oscillation amplitude is greater than said upper amplitude threshold, updating said digital representation to encode a reduced bias current and storing said updated digital representation;
- e) if the comparison determines that said oscillation amplitude is lower than said lower amplitude threshold updating said digital representation to encode an increased bias current and storing said updated digital representation;
- and
- f) repeating steps b) to e) using said updated digital representation as said digital representation.
A method for controlling a bias current of an oscillator having an oscillation amplitude, the method comprising:
- carrying out an initial search algorithm, to determine a digital representation encoding a bias current for providing an oscillation amplitude between an upper threshold and a lower threshold;
- applying a bias current to said oscillator using a digitally controlled current generated based on said determined digital representation;
- and
- subsequent to the initial search algorithm, carrying out an amplitude regulation algorithm to update the digital representation if the oscillation amplitude is measured, by one or more peak detectors, to be outside of said upper and lower thresholds, the amplitude regulation algorithm being different to the initial search algorithm.
An apparatus arranged to control the bias current of an oscillator, the apparatus comprising:
- one or more peak detectors;
- and
- a current digital to analogue converter;
- wherein the apparatus is arranged to:
- a) acquire a digital representation, for the current digital to analogue converter to receive, said digital representation encoding a bias current for supplying to the oscillator;
- b) monitor an oscillation amplitude of the oscillator at a node using the one or more peak detectors;
- and
- c) use the peak detector(s) to carry out a comparison of the oscillation amplitude at the node with an upper amplitude threshold and a lower amplitude threshold, wherein:
- d) if the comparison determines that said oscillation amplitude is greater than said upper amplitude threshold, update said digital representation to encode a reduced bias current and store said updated digital representation;
- e) if the comparison determines that said oscillation amplitude is lower than said lower amplitude threshold, update said digital representation to encode an increased bias current and store updated digital representation;
- and wherein
- f) repeat steps b) to e) using said updated digital representation as said digital representation.
Dependencies are inferred from the claim text.