Quadrature phase relaxation oscillator

Patent metadata

Field	Value
Publication number	US-9257974-B1
Application number	US-201414582916-A
Country	US
Kind code	B1
Filing date	Dec 24, 2014
Priority date	Sep 24, 2014
Publication date	Feb 9, 2016
Grant date	Feb 9, 2016

Abstract

A low voltage quadrature phase wideband relaxation oscillator. An ultra-wideband tuning range from Mega to Giga Hz order is also realized by tuning the I/Q coupling factor, zeros and poles. Preferably, a novel synchronous quadrature injection lock is proposed to validate low noise performance.

First claim

What is claimed is:

1. A quadrature phase relaxation oscillator comprising:
a first relaxation oscillator comprising a first output end and a second output end configured for respectively providing a first output signal and a second output signal, wherein the phase difference between the second output signal and the first output signal is 180 degrees;
a second relaxation oscillator comprising a third output end and a fourth output end configured for respectively providing a third output signal and a fourth output signal, wherein the phase difference between the fourth output signal and the third output signal is 180 degrees and the phase difference between the fourth output signal and the first output signal is more than 180 degrees;
a first current source circuit, electrically connected to the first output end, controlled by the fourth output signal, and selectively providing a first current to the first output end for synthesizing the first output signal;
a second current source circuit, electrically connected to the second output end, controlled by the third output signal, and selectively providing a second current to the second output end for synthesizing the second output signal;
a third current source circuit, electrically connected to the third output end, controlled by the first output signal, and selectively providing a third current to the third output end for synthesizing the third output signal; and
a fourth current source circuit, electrically connected to the fourth output end, controlled by the second output signal, and selectively providing a fourth current to the fourth output end for synthesizing the fourth output signal.

2. The quadrature phase relaxation oscillator according to claim 1 , wherein the first relaxation oscillator comprises a first oscillator current source and a second oscillator current source respectively corresponding to the first output end and the second output end, and
the second relaxation oscillator comprises a third oscillator current source and a fourth oscillator current source respectively corresponding to the third output end and the fourth output end;
wherein the currents provided by the first oscillator current source, the second oscillator current source, the third oscillator current source, and the fourth oscillator current source are respectively different from the currents provided by the first current source circuit, the second current source circuit, the third current source circuit, and the fourth current source circuit.

3. The quadrature phase relaxation oscillator according to claim 1 , wherein the first current source circuit comprises a first transistor having a drain electrode electrically connected to the first output end, a gate electrode electrically connected to the fourth output end, and a source electrode electrically connected to a first current source;
the second current source circuit comprises a second transistor having a drain electrode electrically connected to the second output end, a gate electrode electrically connected to the third output end, and a source electrode electrically connected to a second current source;
the third current source circuit comprises a third transistor having a drain electrode electrically connected to the third output end, a gate electrode electrically connected to the first output end, and a source electrode electrically connected to a third current source; and
the fourth current source circuit comprises a fourth transistor having a drain electrode electrically connected to the fourth output end, a gate electrode electrically connected to the second output end, and a source electrode electrically connected to a fourth current source.

4. The quadrature phase relaxation oscillator according to claim 3 , wherein the first current source circuit, the second current source circuit, the third current source circuit, and the fourth current source circuit share a common source electrode current source.

5. The quadrature phase relaxation oscillator according to claim 3 , wherein the first transistor, the second transistor, the third transistor, and the fourth transistor comprise the NMOS of the same electrical characteristics.

6. The quadrature phase relaxation oscillator according to claim 1 , further comprising:
a first switch, electrically connected between the first output end and the third output end, and electrically conducting or isolating between the first output end and the third output end selectively, and
a second switch, electrically connected between the second output end and the fourth output end, and electrically conducting or isolating between the second output end and the fourth output end selectively;
wherein the first switch or the second switch are electrically conducting and injection locked to an oscillating signal of a low degree of phase noise, when the first output signal and third output signal have the same voltage level or when the second output signal and fourth output signal have the same voltage level.

7. The quadrature phase relaxation oscillator according to claim 1 , wherein the first relaxation oscillator comprises:
a first resistor, having one end connected to a high voltage supply;
a first oscillator transistor, having a drain electrode connected to the other end of the first resistor, and having a gate electrode connected to the second output end, wherein the node between the first resistor and the drain electrode of the first oscillator transistor is configured as the first output end;
a first oscillator current source, having one end connected to a source electrode of the first oscillator transistor, and having the other end connected to the ground;
a second resistor, having one end connected to a high voltage supply;
a second oscillator transistor, having a drain electrode connected to the other end of the second resistor, and having a gate electrode connected to the first output end, wherein the node between the second resistor and the drain electrode of the second oscillator transistor is configured as the second output end;
a second oscillator current source, having one end connected to a source electrode of the second oscillator transistor, and having the other end connected to the ground; and
a first capacitor, having one end connected to the source electrode of the first oscillator transistor, and having the other end connected to the source electrode of the second oscillator transistor; and

wherein the second relaxation oscillator comprises:
a third resistor, having one end connected to a high voltage supply;
a third oscillator transistor, having a drain electrode connected to the other end of the third resistor, and having a gate electrode connected to the fourth output end, wherein the node between the third resistor and the drain electrode of the third oscillator transistor is configured as the third output end;
a third oscillator current source, having one end connected to a source electrode of the third oscillator transistor, and having the other end connected to the ground;
a fourth resistor, having one end connected to a high voltage supply;
a fourth oscillator transistor, having a drain electrode connected to the other end of the fourth resistor, and having a gate electrode connected to the third output end, wherein the node between the fourth resistor and the drain electrode of the fourth oscillator transistor is configured as the fourth output end;
a fourth oscillator current source, having one end connected to a source electrode of the fourth oscillator transistor, and having the other end connected to the ground; and
a second capacitor, having one end connected to the source electrode of the third oscillator transistor, and having the other end connected to the source electrode of the fourth

Assignees

• Univ Nat Chiao Tung

Inventors

• Chen Wei-Zen
• Hong Zheng-Hao
• Liu Yao-Chia

Classifications

• H03K3/0231 Primary

  Astable circuits {(H03K3/0315 takes precedence)} · CPC title

• H03K4/52 Primary

  using two semiconductor devices so coupled that the input of each one is derived from the output of the other, e.g. multivibrator · CPC title

• H03B27/00 Primary

  Generation of oscillations providing a plurality of outputs of the same frequency but differing in phase, other than merely two anti-phase outputs · CPC title

• H03K3/354

  Astable circuits · CPC title