US 11,936,339 B2
Voltage controlled oscillator with series resonant circuit
Alessandro Franceschin, Silea (IT); Andrea Mazzanti, Formigine (IT); and Andrea Pallotta, Rho (IT)
Assigned to STMicroelectronics S.r.l., Agrate Brianza (IT)
Filed by STMicroelectronics S.r.l., Agrate Brianza (IT)
Filed on Aug. 24, 2022, as Appl. No. 17/894,548.
Claims priority of application No. 102021000023000 (IT), filed on Sep. 6, 2021.
Prior Publication US 2023/0081414 A1, Mar. 16, 2023
Int. Cl. H03B 5/12 (2006.01)
CPC H03B 5/1231 (2013.01) [H03B 5/1215 (2013.01); H03B 5/1228 (2013.01); H03B 5/124 (2013.01)] 22 Claims
OG exemplary drawing
 
1. A voltage controlled oscillator, comprising:
a series resonant circuit having a resonance frequency;
wherein the series resonant circuit has a series resistance;
a load having a load resistance; and
an active voltage driving device having an output negative resistance in an operative voltage range at the resonance frequency that is dependent on the load resistance, said active voltage driving device coupled to the series resonant circuit and configured to provide a driving voltage;
wherein the active voltage driving device comprises a cross-coupled differential pair having voltage supply terminals outputting said driving voltage; and
wherein the series resonant circuit is coupled between the voltage supply terminals of the cross-coupled differential pair; and
wherein, at the resonance frequency, an absolute value of the output negative resistance of the active voltage driving device is greater than the series resistance of the series resonant circuit;
wherein the cross-coupled differential pair has current supply terminals and the load is coupled to the active voltage driving device at the current supply terminals; and
a first saturator diode and a second saturator diode coupled in anti-parallel configuration between the current supply terminals of the active voltage driving device.