Symmetric charge pump replica bias detector

Abstract

A charge pump replica bias detector is disclosed which provides a charge pump with a greater working output voltage range or larger output compliance. A larger working range will provide a charge pump with more symmetric source and sink currents than prior designs with a reduction of the multiple frequency sideband levels that occur in a voltage controlled oscillator of a phase-locked loop synthesizer. Further improvements are the prevention of disturbances of the loop filter voltage level due to unwanted leakage currents in a charge pump that are dependent on the value of loop filter voltage. Finally, by providing improved output voltage compliance and limiting loop filter voltage disturbances there are improvements in the reduction in reference frequency feed-through, charge sharing and noise transient coupling and phase noise in the phase-locked loop. Possible applications include but are not limited to charge pump phase-locked loop designs for single chip CMOS multi-band and multi-standard radio frequency transceiver integrated circuits.

Description

[0001]THIS APPLICATION IS BASED ON THE PROVISIONAL APPLICATION No. 60 / 487,614 FILED ON Jul. 17, 2003 and application Ser. No. 10 / 809,033 FILED ON Jul. 13, 2004REFERENCES[0002][1] Chih-Ming Hung and Kenneth K. O, “A Fully integrated 1.5V 5.5 GHz CMOS Phase-Locked Loop”, IEEE JSSC, Vol. 37, No. 4, April 2002.[0003][2] William Wilson, Un-Ku Moon, Kadaba R. Lakshmikumar and Liang Dai “A Self-Calibrating Frequency Synthesizer”, IEEE JSSC, Vol. 35, No. 10, October 2000.BACKGROUND[0004]1. Technical Field of Invention[0005]The present invention relates to a replica bias detector and circuit design used in a high efficiency symmetric CMOS charge pump architecture that can be used in phase-locked loop (PLL) frequency synthesizers. The PLL application examples include but are not limited to radio frequency receivers and transmitters for all wireless communication standards including cellular 2.5G / 3G / 4G wireless communications, optical fiber communications, network communications and storage sy...

AI Technical Summary

Problems solved by technology

However, this type of design suffers from larger internal dynamic voltage swings that increase the reference frequency feed through from the switching elements to the filter load.

However, since the internal circuit nodes settle to their own internal turn-on and turn-off voltages, this leads to potentially long and asymmetric turn-off decays.

In addition, switching transients are still not optimally reduced in these designs.

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