Series-resonance oscillator

Patent metadata

Field	Value
Publication number	US-9755627-B2
Application number	US-201414417040-A
Country	US
Kind code	B2
Filing date	Apr 17, 2014
Priority date	Apr 17, 2014
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

An oscillator circuit comprises a first tank circuit comprising an inductive element and a capacitive element coupled in series between a first voltage rail and a first drive node. A feedback stage is coupled to a first tank output of the first tank circuit and to the first drive node. The feedback stage is arranged to generate, responsive to a first oscillating tank voltage present at the first tank output, a first oscillating drive voltage at the first drive node in-phase with a first oscillating tank current flowing in the inductive element and the capacitive element, thereby causing the oscillator to oscillate in a series resonance mode of the inductive element and the capacitive element.

First claim

The invention claimed is:

1. An oscillator circuit comprising:
a first tank circuit comprising an inductive element and a capacitive element coupled in series between a voltage rail and a first drive node; and
a feedback stage coupled to a first tank output of the first tank circuit and to the first drive node;
wherein the feedback stage is arranged to generate, responsive to a first oscillating tank voltage present at the first tank output, a first oscillating drive voltage at the first drive node in-phase with an oscillating tank current flowing in the inductive element and the capacitive element, thereby causing the oscillator circuit to oscillate in a series resonance mode of the inductive element and the capacitive element.

2. The oscillator circuit as claimed in claim 1 , wherein the feedback stage is arranged to generate the first oscillating drive voltage having a substantially rectangular waveform.

3. The oscillator circuit as claimed in claim 1 , wherein the first tank circuit is arranged to generate, responsive to the first oscillating drive voltage, the first oscillating tank voltage in-phase with the first oscillating drive voltage, and wherein the feedback stage comprises a first driver arranged to generate, responsive to the first oscillating tank voltage, the first oscillating drive voltage in-phase with the first oscillating tank voltage.

4. The oscillator circuit as claimed in claim 1 , wherein
the first tank circuit is arranged to generate, responsive to the first oscillating drive voltage, the first oscillating tank voltage one hundred and eighty degrees out-of-phase with the first oscillating drive voltage, and wherein the feedback stage comprises a first driver arranged to generate, responsive to the first oscillating tank voltage, the first oscillating drive voltage one hundred and eighty degrees out-of-phase with the first oscillating tank voltage by applying signal inversion to the first oscillating tank voltage.

5. The oscillator circuit as claimed in claim 1 , wherein the first tank circuit is arranged to generate, responsive to the first oscillating drive voltage, the first oscillating tank voltage in-phase with the first oscillating drive voltage, and wherein the feedback stage comprises:
a second driver arranged to generate a second oscillating drive voltage by applying signal inversion to the first oscillating tank voltage;
a second tank circuit arranged to generate, responsive to the second oscillating drive voltage, a second oscillating tank voltage in-phase with the second oscillating drive voltage; and
a first driver arranged to generate the first oscillating drive voltage by applying signal inversion to the second oscillating tank voltage.

6. The oscillator circuit as claimed in claim 1 , wherein the first tank circuit is arranged to generate, responsive to the first oscillating drive voltage, the first oscillating tank voltage one hundred and eighty degrees out-of-phase with the first oscillating drive voltage, and wherein the feedback stage comprises:
a second driver arranged to generate a second oscillating drive voltage by applying signal inversion to the first oscillating tank voltage;
a second tank circuit arranged to generate, responsive to the second oscillating drive voltage, a second oscillating tank voltage in-phase with the second oscillating drive voltage; and
a first driver arranged to generate the first oscillating drive voltage in-phase with the second oscillating tank voltage.

7. The oscillator circuit as claimed in claim 1 , wherein the first tank circuit is arranged to generate, responsive to the first oscillating drive voltage, the first oscillating tank voltage one hundred and eighty degrees out-of-phase with the first oscillating drive voltage, and wherein the feedback stage comprises:
a second driver arranged to generate, responsive to the first oscillating tank voltage, a second oscillating drive voltage in-phase with the first oscillating tank voltage;
a second tank circuit arranged to generate, responsive to the second oscillating drive voltage, a second oscillating tank voltage one hundred and eighty degrees out-of-phase with the second oscillating drive voltage; and
a first driver arranged to generate, responsive to the second oscillating tank voltage, the first oscillating drive voltage in-phase with the second oscillating tank voltage.

8. The oscillator circuit as claimed in claim 3 , wherein the first tank circuit comprises a sensor device arranged to generate the first oscillating tank voltage responsive to the first oscillating tank current.

9. The oscillator circuit as claimed in claim 8 , wherein the sensor device comprises one of a resistive element and a transformer coupled in series with the inductive element and the capacitive element between the voltage rail and the first drive node.

10. The oscillator circuit as claimed in claim 8 , wherein the sensor device is magnetically coupled to the inductive element for generating by magnetic induction the first oscillating tank voltage responsive to the first oscillating tank current.

11. The oscillator circuit as claimed in claim 1 , wherein
the first tank circuit is arranged to generate, responsive to the first oscillating drive voltage, the first oscillating tank voltage having a phase lagging by ninety degrees a phase of the first oscillating drive voltage, and wherein the feedback stage comprises a phase shifting stage arranged to generate a first intermediate oscillating voltage by applying a phase lag of ninety degrees to the first oscillating tank voltage and the oscillator circuit further comprises a first driver arranged to generate the first oscillating drive voltage by applying signal inversion to the first intermediate oscillating voltage.

12. The oscillator circuit as claimed in claim 1 , wherein
the first tank circuit is arranged to generate, responsive to the first oscillating drive voltage, the first oscillating tank voltage having a phase leading by ninety degrees a phase of the first oscillating drive voltage, and wherein the feedback stage comprises a phase shifting stage arranged to generate a first intermediate oscillating voltage by applying a phase lag of ninety degrees to the first oscillating tank voltage, further comprising a first driver arranged to generate the first oscillating drive voltage in response to, and in-phase with, the first intermediate oscillating voltage.

13. The oscillator circuit as claimed in claim 1 , wherein the first tank circuit is arranged to generate, responsive to the first oscillating drive voltage, the first oscillating tank voltage having a phase lagging by ninety degrees a phase of the first oscillating drive voltage, and wherein the feedback stage comprises:
a first phase shift circuit arranged to generate a first intermediate oscillating voltage by applying a phase lag of ninety degrees to the first oscillating tank voltage;
a second driver arranged to generate, responsive to the first intermediate oscillating voltage, a second oscillating drive voltage in-phase with the first intermediate oscillating voltage,
a second tank circuit arranged to generate, responsive to the second oscillating drive voltage, a second oscillating tank voltage having a phase lagging by ninety degrees a phase of the second oscillating drive voltage;
a second phase shift circuit arranged to generate a second intermediate oscillating voltage by applying a phase lag of ninety degrees to the second oscillating tank voltage; and
a first driver arranged to generate, responsive to the second intermediate oscillating voltage, the first oscillating drive voltage in-phase with the second intermediate

Assignees

• Ericsson Telefon Ab L M

Inventors

• Andreani Pietro
• Fanori Luca
• Mattsson Thomas

Classifications

• H03B5/12 Primary

  active element in amplifier being semiconductor device (H03B5/14 takes precedence) · CPC title

• H03K5/145 Primary

  by the use of resonant circuits · CPC title

• H03B5/18

  with frequency-determining element comprising distributed inductance and capacitance · CPC title

• H03K3/354

  Astable circuits · CPC title

• H03B5/1228

  the amplifier comprising one or more field effect transistors · CPC title