Frequency multiplier and method for frequency multiplying

Patent metadata

Field	Value
Publication number	US-11005485-B2
Application number	US-201916447599-A
Country	US
Kind code	B2
Filing date	Jun 20, 2019
Priority date	Jun 21, 2018
Publication date	May 11, 2021
Grant date	May 11, 2021

Abstract

A frequency multiplier comprises a phase generator configured to receive an oscillation signal and to provide at phase generator outputs versions of the oscillation signal, which are phase-shifted with respect to each other. An injection-locked ring oscillator comprises a plurality of stages, wherein each of the phase generator outputs is coupled to a different stage of the plurality of stages for multi-point injection. A combiner combines output signals of the plurality of stages of the injection-locked ring oscillator into a signal having a frequency which is a multiple of a frequency of the oscillation signal.

First claim

The invention claimed is:

1. A frequency multiplier comprising:
a phase generator configured to:
receive an oscillation signal, and
provide, at phase generator outputs, versions of the oscillation signal, which are phase-shifted with respect to each other;

an injection-locked ring oscillator comprising a plurality of stages,
wherein each of the phase generator outputs is directly connected to a different stage of the plurality of stages of the injection-locked ring oscillator for multi-point injection; and

a combiner configured to combine output signals of the plurality of stages of the injection-locked ring oscillator into an output signal having a frequency which is a multiple of a frequency of the oscillation signal.

2. The frequency multiplier of claim 1 , wherein the phase generator comprises N phase generator outputs,
wherein the versions of the oscillation signal are phase-shifted by a phase shift of 360°/N with respect to each other,
wherein the injection-locked ring oscillator comprises N stages,
wherein the frequency of the output signal is N times the frequency of the oscillation signal, and
wherein N is an integer number equal to or larger than two.

3. The frequency multiplier of claim 1 , wherein the phase generator comprises a poly-phase filter.

4. The frequency multiplier of claim 1 , wherein the combiner is an edge combiner configured to combine edges of the output signals of the plurality of stages of the injection-locked ring oscillator into the output signal.

5. The frequency multiplier of claim 4 , wherein the edge combiner comprises a set of transistors,
wherein each of the output signals of the plurality of stages of the injection-locked ring oscillator is provided to a control terminal of a respective transistor of the set of transistors, and
wherein first terminals of the set of transistors are coupled to a common voltage source and second terminals of the set of transistors are coupled to a reference potential.

6. The frequency multiplier of claim 1 , wherein each stage of the plurality of stages of the injection-locked ring oscillator comprises an injection transistor configured to inject an injection current into a respective stage, and each of the phase generator outputs is coupled to a control terminal of a respective injection transistor.

7. The frequency multiplier of claim 1 , wherein the oscillation signal is a differential signal, the phase generator is a differential phase generator, the phase generator outputs are differential phase generator outputs, the injection-locked ring oscillator is a differential injection-locked ring oscillator, and the combiner is a differential combiner.

8. The frequency multiplier of claim 7 , wherein:
each stage of the plurality of stages of the differential injection-locked ring oscillator comprises a first injection transistor, a second injection transistor, a first inverter transistor, a second inverter transistor, and a load,
a first terminal of the first inverter transistor and a first terminal the first injection transistor are connected to a first terminal of a differential output of a respective stage,
a first terminal of the second inverter transistor and a first terminal of the second injection transistor are connected to a second terminal of the differential output of the respective stage,
a second terminal of the first inverter transistor and a second terminal of the second inverter transistor are connected to a reference potential via a first current limiter,
a second terminal of the first injection transistor and a second terminal of the second injection transistor are connected to the reference potential via a second current limiter,
the load is connected between a voltage source and the first terminals of the first inverter transistor and the second inverter transistor,
a control terminal of the first inverter transistor is connected to a first terminal of a differential output of another stage of the differential injection-locked ring oscillator,
a control terminal of the second inverter transistor is connected to a second terminal of the differential output of the other stage of the differential injection-locked ring oscillator, and
a control terminal of the first injection transistor and a control terminal of the second injection transistor are connected to one differential output of the differential phase generator.

9. The frequency multiplier of claim 8 , wherein:
the load comprises a first load transistor and a second load transistor,
a first terminal of the first load transistor is connected to the first terminal of the first inverter transistor,
a first terminal of the second load transistor is connected to the first terminal of the second inverter transistor,
a second terminal of the first load transistor and a second terminal of the second load transistor are connected to the voltage source,
a control terminal of the first load transistor is connected to the first terminal of the second load transistor, and
a control terminal of the second load transistor is connected to the first terminal of the first load transistor.

10. A signal generator comprising:
an oscillator configured to generate an oscillation signal; and
a frequency multiplier comprising:
a phase generator configured to:
receive the oscillation signal, and
provide, at phase generator outputs, versions of the oscillation signal, which are phase-shifted with respect to each other;

an injection-locked ring oscillator comprising a plurality of stages,
wherein each of the phase generator outputs is directly connected to a different stage of the plurality of stages of the injection-locked ring oscillator for multi-point injection; and

a combiner configured to combine output signals of the plurality of stages of the injection-locked ring oscillator into an output signal having a frequency which is a multiple of a frequency of the oscillation signal.

11. The signal generator of claim 10 , wherein the oscillator is a voltage controlled oscillator configured to generate the oscillation signal with a variable oscillation frequency.

12. The signal generator of claim 10 , wherein:
each stage of the plurality of stages of the injection-locked ring oscillator comprises a first injection transistor, a second injection transistor, a first inverter transistor, a second inverter transistor, and a load,
a first terminal of the first inverter transistor and a first terminal of the first injection transistor are connected to a first terminal of an output of a respective stage,
a first terminal of the second inverter transistor and a first terminal of the second injection transistor are connected to a second terminal of the output of the respective stage,
a second terminal of the first inverter transistor and a second terminal of the second inverter transistor are connected to a reference potential via a first current limiter,
a second terminal of the first injection transistor and a second terminal of the second injection transistor are connected to the reference potential via a second current limiter,
the load is connected between a voltage source and the first terminals of the first inverter transistor and the second inverter transistor,
a control terminal of the first inverter transistor is connected to a first terminal of an output of another stage of the injection-locked ring oscillator,
a control terminal of the second inverter transistor is connected to a second terminal of the output of the other stage of the injection-locked ring oscillator, and
a control terminal of the first injection transistor and a control terminal of the second injection transistor are connected to o

Assignees

• Infineon Technologies Ag

Inventors

• Bassi Mateo
• Padovan Fabio

Classifications

• H03B19/14 Primary

  by means of a semiconductor device · CPC title

• H03K5/00006

  Changing the frequency (modulating pulses H03K7/00; frequency dividers H03K21/00 - H03K29/00; additive or subtractive mixing of two pulse rates into one G06F7/605; pulse rate dividers G06F7/68) · CPC title

• H03K3/0315

  Ring oscillators · CPC title

• H03L7/24

  using a reference signal directly applied to the generator · CPC title

• H03L7/0996 Primary

  Selecting a signal among the plurality of phase-shifted signals produced by the ring oscillator · CPC title