Low power current re-using transformer-based dual-band voltage controlled oscillator

Patent metadata

Field	Value
Publication number	US-2016373057-A1
Application number	US-201514745033-A
Country	US
Kind code	A1
Filing date	Jun 19, 2015
Priority date	Jun 19, 2015
Publication date	Dec 22, 2016
Grant date	—

Abstract

A dual-band voltage controlled oscillator (VCO) includes: a first oscillator circuit including a first inductor; a second oscillator circuit including a second inductor; a first mode switch configured to electrically connect or disconnect a first output terminal of the first oscillator circuit and a first output terminal of the second oscillator circuit; a second mode switch configured to electrically connect or disconnect a second output terminal of the first oscillator circuit and a second output terminal of the second oscillator circuit; a third mode switch configured to electrically connect or disconnect a first terminal of the first inductor and a first terminal of the second inductor; and a fourth mode switch configured to electrically connect or disconnect a second terminal of the first inductor and a second terminal of the second inductor.

First claim

1 . A dual-band voltage controlled oscillator (VCO), comprising:
a first oscillator circuit comprising a first inductor; a second oscillator circuit comprising a second inductor; a first mode switch configured to electrically connect or disconnect a first output terminal of the first oscillator circuit to a first output terminal of the second oscillator circuit; a second mode switch configured to electrically connect or disconnect a second output terminal of the first oscillator circuit to a second output terminal of the second oscillator circuit; a third mode switch configured to electrically connect or disconnect a first terminal of the first inductor to a first terminal of the second inductor; and a fourth mode switch configured to electrically connect or disconnect a second terminal of the first inductor to a second terminal of the second inductor.

2 . The dual-band VCO of claim 1 , further comprising:
a first coupling capacitor configured to electrically couple the first output terminal of the first oscillator circuit to the first output terminal of the second oscillator circuit; and a second coupling capacitor configured to electrically couple the second output terminal of the first oscillator circuit to the second output terminal of the second oscillator circuit.

3 . The dual-band VCO of claim 2 , wherein the dual-band VCO operates in a low band configuration with the first mode switch and the second mode switch in an open state and the third mode switch and the fourth mode switch in a closed state.

4 . The dual-band VCO of claim 3 , wherein in the open state the first mode switch disconnects the first output terminal of the first oscillator circuit from the first output terminal of the second oscillator circuit and causes the first coupling capacitor to electrically couple the first output terminal of the first oscillator circuit to the first output terminal of the second oscillator circuit; and
wherein in the open state the second mode switch disconnects the second output terminal of the first oscillator circuit from the second output terminal of the second oscillator circuit and causes the second coupling capacitor to electrically couple the second output terminal of the first oscillator circuit to the second output terminal of the second oscillator circuit.

5 . The dual-band VCO of claim 3 , wherein in the closed state the third mode switch connects the first terminal of the first inductor to the first terminal of the second inductor;
wherein in the closed state the fourth mode switch connects the second terminal of the first inductor to the second terminal of the second inductor.

6 . The dual-band VCO of claim 2 , wherein the dual-band VCO operates in a high band configuration with the first mode switch and the second mode switch in a closed state and the third mode switch and the fourth mode switch in an open state.

7 . The dual-band VCO of claim 6 , wherein in the closed state the first mode switch short-circuits the first coupling capacitor and electrically couples the first output terminal of the first oscillator circuit to the first output terminal of the second oscillator circuit; and
wherein in the closed state the second mode switch short-circuits the second coupling capacitor and electrically couples the second output terminal of the first oscillator circuit to the second output terminal of the second oscillator circuit.

8 . The dual-band VCO of claim 6 , wherein in the open state the third mode switch causes an electrical connection between the second terminal of the first inductor and the first terminal of the second inductor;
wherein in the open state the fourth mode switch causes an electrical connection between the first terminal of the first inductor and the second terminal of the second inductor.

9 . The dual-band VCO of claim 1 , wherein the first inductor and the second inductor are configured as a transformer.

10 . The dual-band VCO of claim 9 , wherein the transformer comprises a planar transformer having the second inductor disposed within an area described by the first inductor.

11 . The dual-band VCO of claim 9 , wherein the first inductor and the second inductor have a same inductance value.

12 . The dual-band VCO of claim 9 , wherein the transformer has a coupling coefficient of about 0.2 between the first inductor and the second inductor.

13 . The dual-band VCO of claim 1 , wherein the first mode switch, the second mode switch, the third mode switch, and the fourth mode switch are selected from a group consisting of n-channel metal-oxide semiconductor (NMOS) transistors, p-channel metal-oxide semiconductor (PMOS) transistors, and microelectromechanical switches.

14 . The dual-band VCO of claim 1 , further comprising:
a first amplifier circuit comprising a cross-coupled pair of p-channel metal-oxide semiconductor (PMOS) transistors coupled to the first inductor; and a second amplifier circuit comprising a cross-coupled pair of n-channel metal-oxide semiconductor (NMOS) transistors coupled to the second inductor.

15 . The dual-band VCO of claim 14 , further comprising:
a first degeneration impedance configured to couple the first amplifier circuit to a first power supply; and a second degeneration impedance configured to couple the second amplifier circuit to a second power supply.

16 . A mobile communication device, comprising:
a phase-locked loop (PLL); and a dual-band voltage controlled oscillator (VCO) configured to generate an output signal to the PLL, the dual-band VCO comprising: a first oscillator circuit comprising a first inductor; a second oscillator circuit comprising a second inductor; a first mode switch configured to electrically connect or disconnect a first output terminal of the first oscillator circuit to a first output terminal of the second oscillator circuit; a second mode switch configured to electrically connect or disconnect a second output terminal of the first oscillator circuit to a second output terminal of the second oscillator circuit; a third mode switch configured to electrically connect or disconnect a first terminal of the first inductor to a first terminal of the second inductor; and a fourth mode switch configured to electrically connect or disconnect a second terminal of the first inductor to a second terminal of the second inductor.

17 . The mobile communication device of claim 16 , wherein the dual-band VCO further comprises:
a first coupling capacitor configured to electrically couple the first output terminal of the first oscillator circuit to the first output terminal of the second oscillator circuit; and a second coupling capacitor configured to electrically couple the second output terminal of the first oscillator circuit to the second output terminal of the second oscillator circuit.

18 . The mobile communication device of claim 17 , wherein the dual-band VCO operates in a low band configuration with the first mode switch and the second mode switch in an open state and the third mode switch and the fourth mode switch in a closed state.

19 . The mobile communication device of claim 18 , wherein in the open state the first mode switch disconnects the first output terminal of the first oscillator circuit from the first output terminal of the second oscillator circuit and causes the first coupling capacitor to electrically couple the first output terminal of the first oscillator circuit to the first output terminal of the second oscillator circuit; and
wherein in the open state the second mode switch disc

Assignees

• Qualcomm Inc

Inventors

• Farazian Mohammad
• Moslehi Bajestan Masoud
• Tang Yiwu
• Park Jong Min
• Rong Sujiang

Classifications

• H03B5/1212 Primary

  the amplifier comprising a pair of transistors, wherein an output terminal of each being connected to an input terminal of the other, e.g. a cross coupled pair · CPC title

• H03B5/124 Primary

  the means comprising a voltage dependent capacitance · CPC title

• H03B5/1215

  the current source or degeneration circuit being in common to both transistors of the pair, e.g. a cross-coupled long-tailed pair · CPC title

• H03B5/1256

  the means comprising a variable inductance · CPC title

• H03B5/1296

  the feedback circuit comprising a transformer · CPC title