Patent ID: 11962315
Assignee: TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A phase-locked loop, comprising a voltage controlled oscillator, wherein the voltage controlled oscillator comprises:
an inductor and a capacitor, connected in parallel; and
connected in parallel therewith, a negative resistance structure, wherein a first terminal of the negative resistance structure is connected to respective first terminals of the inductor and the capacitor, wherein a second terminal of the negative resistance structure is connected to respective second terminals of the inductor and the capacitor, wherein the negative resistance structure exhibits a tunable capacitance, wherein a frequency of an output of the voltage controlled oscillator can be tuned by a control input signal, and wherein said control input signal is generated in the phase-locked loop;
wherein the negative resistance structure comprises first and second transistors, and wherein each of the first and second transistors has a respective transistor conduction path between first and second terminals thereof and has a control terminal;
wherein there is a first conduction path between the first terminal of the first transistor and the control terminal of the second transistor, wherein there is a second conduction path between the control terminal of the first transistor and the first terminal of the second transistor, and wherein the control terminal of at least one of the first and second transistors is biased by the control input signal; and
wherein a parasitic capacitance of said at least one of the first and second transistors can be tuned by the control input signal, in order to tune the frequency of the output of the voltage controlled oscillator, and the frequency of oscillation of the phase-locked loop.