Frequency synthesizer
AssigneeSilicon Laboratories Inc.
InventorsMustafa H. Koroglu, Sherry X. Wu, Ramin Khoini-Poorfard, Alessandro Piovaccari
Life of this patent
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Abstract
A frequency synthesizer includes a controlled oscillator configured to extend a temperature range and phase noise of the synthesizer without compromising the frequency coverage of the synthesizer. The frequency synthesizer also includes bias generation circuitry that sets a bias current of a charge pump to reduce bandwidth variations of the synthesizer. The frequency synthesizer further includes switching circuitry to dynamically turn a charge pump on and off to reduce effects of current leakage in the charge pump.
Claims20
A frequency synthesizer comprising:
- a phase detector configured to detect a phase difference between a reference signal and a phase output signal;
- a first charge pump configured to supply first amount of charge responsive to the phase difference;
- a second charge pump configured to supply second amount of charge responsive to the phase difference;
- a direct path loop filter configured to generate a first filtered input responsive to the first amount of charge;
- an integrating path loop filter configured to generate a second filtered input responsive to the second amount of charge;
- and
- a controlled oscillator configured to generate the phase output signal by applying a first gain to the first filtered input and applying a second gain to the second filtered input, the second gain greater than the first gain.
A communications device comprising:
- local oscillator generation circuitry including a frequency synthesizer with a charge pump and bias circuitry, the bias circuitry configured to set a bias current signal provided to the charge pump based on a calibrated resistor and a reference bias voltage, the local oscillator generation circuitry configured to generate a mixing signal from a phase output signal generated by the frequency synthesizer;
- communications circuitry configured to generate a digital signal from the analog input signal using the mixing signal;
- and
- processing circuitry configured to generate the communications output signal responsive to the digital signal from the communications circuitry.
A media system comprising:
- a communications device configured to receive an analog input signal and generate a communications output signal, the communications device includes:
- local oscillator generation circuitry including a frequency synthesizer with a charge pump, the frequency synthesizer configured to turn off the charge pump between comparisons of a phase reference signal and a phase output signal, the local oscillator generation circuitry configured to generate a mixing signal from the phase output signal;
- communications circuitry configured to generate a digital signal from the analog input signal using the mixing signal;
- and
- processing circuitry configured to generate the communications output signal responsive to the digital signal from the communications circuitry;
- a processing unit configured to generate a media signal in response to the communications output signal from the communications device.
Dependencies are inferred from the claim text.