Stmicroelectronics S.r.l.

Alessandro D'Aquila

Giuseppe Gramegna

Benedetto Marco Marletta

Antonio Magazzu

Antonio Magazz'

B Marco Marletta

A method and a circuit for minimizing glitches in phase-locked loops is presented. The circuit includes an input terminal connected to an input of a phase detector; a series of a charge pump generator, a filter and a voltage controlled oscillator connected downstream of the phase detector; and a frequency divider feedback connected between an output of the voltage controlled oscillator and a second input of the phase detector. The circuit provides for the inclusion of a compensation circuit connected between the charge pump generator and the filter to absorb an amount of the charge passed therethrough. This compensation circuit includes a storage element connected in series to two switches. The first switch is coupled to and controlled by an output of the charge pump and the second switch is coupled to and controlled by an output of a phase detector.

Method and circuit for minimizing glitches in phase-locked loops

A high-precision biasing circuit is provided for a CMOS cascode stage with inductive load and degeneration. The cascode stage includes at least two MOS transistors serially connected between a first voltage reference and a second voltage reference. The biasing circuit includes at least a first MOS replica transistor and a second MOS replica transistor, and two current generators for biasing the first and second MOS replica transistors. A circuit block detects a voltage value on a terminal of the second replica MOS transistor and applies a voltage to a gate terminal of the first replica transistor. Two circuit block implementations include a voltage amplifier and a folded cascode amplifier closed in a shunt feedback. Both implementations allow the threshold voltages of the cascode stage transistors to be tracked, as well as their Early and body effects.

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Palermo, Italy

Alessandro D'Aquila