Magnetically pumped voltage controlled oscillator

Patent metadata

Field	Value
Publication number	US-2020212843-A1
Application number	US-201916681771-A
Country	US
Kind code	A1
Filing date	Nov 12, 2019
Priority date	Jan 2, 2019
Publication date	Jul 2, 2020
Grant date	—

Abstract

A voltage controlled oscillator includes a first inductor, a second inductor, a first metal oxide semiconductor (MOS) transistor, a second MOS transistor, and an inductor-capacitor (LC) tank circuit. A first end of the first inductor and a first end of the second inductor are coupled to a first power rail. A drain node of the first MOS transistor is coupled to a second end of the first inductor. A drain node of the second MOS transistor is coupled to a second end of the second inductor. Source nodes of the first MOS transistor and the second MOS transistor are coupled to a second power rail. The LC tank circuit is coupled to gate nodes of the first MOS transistor and the second MOS transistor, wherein energy is magnetically pumped into the LC tank circuit through the first inductor and the second inductor.

First claim

What is claimed is:

1 . A voltage controlled oscillator comprising:
a first inductor, having a first end and a second end, wherein the first end of the first inductor is coupled to a first power rail; a second inductor, having a first end and a second end, wherein the first end of the second inductor is coupled to the first power rail; a first metal oxide semiconductor (MOS) transistor, having a gate node, a drain node, and a source node, wherein the drain node of the first MOS transistor is coupled to the second end of the first inductor, and the source node of the first MOS transistor is coupled to a second power rail; a second MOS transistor, having a gate node, a drain node, and a source node, wherein the drain node of the second MOS transistor is coupled to the second end of the second inductor, and the source node of the second MOS transistor is coupled to the second power rail; and an inductor-capacitor (LC) tank circuit, coupled to the gate node of the first MOS transistor and the gate node of the second MOS transistor, wherein energy is magnetically pumped into the LC tank circuit through the first inductor and the second inductor, such that there is no direct connection between the LC tank circuit and the drain node of the first MOS transistor and there is no direct connection between the LC tank circuit and the drain node of the second MOS transistor.

2 . The voltage controlled oscillator of claim 1 , wherein each of the first MOS transistor and the second MOS transistor is an N-channel metal oxide semiconductor (NMOS) transistor, and a reference voltage delivered by the first power rail is higher than a reference voltage delivered by the second power rail.

3 . The voltage controlled oscillator of claim 1 , wherein each of the first MOS transistor and the second MOS transistor is a P-channel metal oxide semiconductor (PMOS) transistor, and a reference voltage delivered by the first power rail is lower than a reference voltage delivered by the second power rail.

4 . The voltage controlled oscillator of claim 1 , wherein the LC tank circuit comprises:
a capacitor, wherein a first end of the capacitor is coupled to the gate node of the second MOS transistor, and a second end of the capacitor is coupled to the gate node of the first MOS transistor; a third inductor, magnetically coupled to the first inductor, wherein a first end of the third inductor is coupled to a bias voltage, and a second end of the third inductor is coupled to the first end of the capacitor; and a fourth inductor, magnetically coupled to the second inductor, wherein a first end of the fourth inductor is coupled to the bias voltage, and a second end of the fourth inductor is coupled to the second end of the capacitor.

5 . The voltage controlled oscillator of claim 4 , wherein a resonant frequency of the LC tank circuit is independent of inductance values of the first inductor and the second inductor.

6 . The voltage controlled oscillator of claim 4 , wherein a resonant frequency of the LC tank circuit is independent of a coupling coefficient between the first inductor and the third inductor and a coupling coefficient between the second inductor and the fourth inductor.

7 . The voltage controlled oscillator of claim 4 , wherein the third inductor and the fourth inductor have a same inductance value, mutual induction between the first inductor and the third inductor and mutual induction between the second inductor and the fourth inductor have a same mutual inductance value, and a ratio of a voltage swing at the gate node of each of the first MOS transistor and the second MOS transistor to a voltage swing at the drain node of each of the first MOS transistor and the second MOS transistor is equal to a ratio of said same inductance value to said same mutual inductance value.

8 . The voltage controlled oscillator of claim 4 , wherein a voltage swing at the gate node of each of the first MOS transistor and the second MOS transistor is larger than a voltage swing at the drain node of each of the first MOS transistor and the second MOS transistor.

9 . The voltage controlled oscillator of claim 8 , wherein the voltage swing at the gate node and the voltage swing at the gate node are configured to prevent any of the first MOS transistor and the second MOS transistor from entering a triode region.

10 . A voltage controlled oscillator comprising:
a first inductor, having a first end and a second end; a second inductor, having a first end and a second end, wherein the first end of the second inductor is coupled to the first end of the first inductor; a first P-channel metal oxide semiconductor (PMOS) transistor, having a gate node, a drain node, and a source node, wherein the drain node of the first PMOS transistor is coupled to the second end of the first inductor, and the source node of the first MOS transistor is coupled to a first power rail; a second PMOS transistor, having a gate node, a drain node, and a source node, wherein the drain node of the second PMOS transistor is coupled to the second end of the second inductor, and the source node of the second PMOS transistor is coupled to the first power rail; a first N-channel metal oxide semiconductor (NMOS) transistor, having a gate node, a drain node, and a source node, wherein the drain node of the first NMOS transistor is coupled to the second end of the first inductor, and the source node of the first MOS transistor is coupled to a second power rail; a second NMOS transistor, having a gate node, a drain node, and a source node, wherein the drain node of the second NMOS transistor is coupled to the second end of the second inductor, and the source node of the second NMOS transistor is coupled to the second power rail; and an inductor-capacitor (LC) tank circuit, coupled to the gate node of the first PMOS transistor, the gate node of the second PMOS transistor, the gate node of the first NMOS transistor, and the gate node of the second NMOS transistor, wherein energy is magnetically pumped into the LC tank circuit through the first inductor and the second inductor, such that there is no direct connection between the LC tank circuit and the drain node of each of the first PMOS transistor and the first NMOS transistor and there is no direct connection between the LC tank circuit and the drain node of each of the second PMOS transistor and the second NMOS transistor.

11 . The voltage controlled oscillator of claim 10 , wherein the LC tank circuit comprises:
a capacitor, wherein a first end of the capacitor is coupled to the gate node of the second PMOS transistor and the gate node of the second NMOS transistor, and a second end of the capacitor is coupled to the gate node of the first PMOS transistor and the gate node of the first NMOS transistor; a third inductor, magnetically coupled to the first inductor, wherein a first end of the third inductor is coupled to a first bias voltage, and a second end of the third inductor is coupled to the first end of the capacitor; and a fourth inductor, magnetically coupled to the second inductor, wherein a first end of the fourth inductor is coupled to the first bias voltage, and a second end of the fourth inductor is coupled to the second end of the capacitor.

12 . The voltage controlled oscillator of claim 11 , wherein the first end of the first inductor and the first end of the second inductor are coupled to the first bias voltage.

13 . The voltage controlled oscillator of claim 11 , wherein the first end of the first inductor and the first end of the second inductor are coupled to a second bias voltage, and a setting of the first bias voltage is independent of a

Assignees

• Mediatek Inc

Inventors

• Hsueh Yu-Li
• Huang Po-Chun
• Lin Ang-Sheng
• Chiu Wei-Hao

Classifications

• H03L7/099

  concerning mainly the controlled oscillator of the loop · CPC title

• H03B5/1231

  the amplifier comprising one or more bipolar transistors · CPC title

• H03B5/1228 Primary

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

• H03B5/1218

  the generator being of the balanced type · CPC title

• H03B5/1296

  the feedback circuit comprising a transformer · CPC title