# US 2019/0173474 A1 · Ring oscillator circuit with frequency stabilization

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- Number: US 2019/0173474 A1
- Document ID: US20190173474A1
- Status: Published application
- Kind: A1
- Application number: 15/832,502
- Filed: 2017-12-05
- Published: 2019-06-06
- Earliest claimed: 2017-12-05
- Assignees: BAE Systems Information and Electronic Systems Integration Inc.
- Applicants: Bae Systems Information and Electronic Systems Integration Inc.
- Inventors: KENNETH R. KNOWLES; DANIEL PIRKL
- Web page: https://patentgrep.com/patent/US20190173474A1

## CPC

- H03L 7/00: Automatic control of frequency or phase; Synchronisation
- H03K 3/011: Modifications of generator to compensate for variations in physical values, e.g. voltage, temperature {(to maintain energy constant H03K3/015)}
- H03K 3/0315: {Ring oscillators}
- H03L 1/022: {by indirect stabilisation, i.e. by generating an electrical correction signal which is a function of the temperature (H03L1/021 takes precedence)}
- H03L 7/0995: {the oscillator comprising a ring oscillator}
- H03L: AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES (generation of oscillations H03B)
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)

## Abstract

A ring oscillator circuit is disclosed. The ring oscillator in one embodiment includes an odd number of inverters connected in a loop fashion, a current mirror having a drain of a first transistor connected to the inverters, and a self-biased inverter connected to a drain of a second transistor of the current mirror.

## Claims

### Claim 1

A ring oscillator comprising:
a plurality of inverters connected in a loop fashion;
a current mirror having a drain of a first transistor connected to said plurality of inverters; and
a self-biased inverter connected to a drain of a second transistor of said current mirror.

### Claim 2 (depends on 1)

The ring oscillator of claim 1, wherein said drain of said first transistor of said current mirror is connected to sources of transistors within said plurality of inverters.

### Claim 3 (depends on 1)

The ring oscillator of claim 1, wherein sizes of said first and second transistors of said current mirror are selected to regulate a drain current of said first transistor to be approximately equal to a drain current of said second transistor.

### Claim 4 (depends on 1)

The ring oscillator of claim 1, wherein said first transistor of said current mirror is diode-connected.

### Claim 5 (depends on 1)

The ring oscillator of claim 1, wherein an output of said self-biased inverter is connected to an input of said self-biased inverter.

### Claim 6 (depends on 1)

The ring oscillator of claim 1, wherein a drain of a transistor within said self-biased inverter is connected to said drain of said second transistor of said current mirror.

### Claim 7 (depends on 1)

The ring oscillator of claim 1, wherein dimensions of transistors within said self-biased inverter is scaled to change the magnitude of current to said transistors within said self-biased inverter relative to current to said first transistor of said current mirror.

### Claim 8 (depends on 1)

The ring oscillator of claim 1, wherein said self-biased inverter includes a plurality of inverters connected in parallel.

### Claim 9 (depends on 1)

The ring oscillator of claim 1, wherein said transistors have channel length of less than 45 nm.