# US 2014/0197897 A1 · Precision oscillator with temperature compensation

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2014/0197897 A1
- Document ID: US20140197897A1
- Status: Published application
- Kind: A1
- Application number: 14/218,256
- Filed: 2014-03-18
- Published: 2014-07-17
- Earliest claimed: 2011-01-19
- Assignees: Marvell World Trade Ltd.
- Applicants: Marvell World Trade Ltd.
- Inventors: Dennis SINITSKY; Tao SHUI
- Web page: https://patentgrep.com/patent/US20140197897A1

## CPC

- H03K 3/02: Generators characterised by the type of circuit or by the means used for producing pulses (H03K3/64 - H03K3/84 take precedence)
- H03K 3/011: Modifications of generator to compensate for variations in physical values, e.g. voltage, temperature {(to maintain energy constant H03K3/015)}
- H03K 3/0231: Astable circuits {(H03K3/0315 takes precedence)}
- H03K 4/502: the capacitor being charged from a constant-current source
- H03L 1/00: Stabilisation of generator output against variations of physical values, e.g. power supply
- H03L 1/02: against variations of temperature only
- 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)
- H03L: AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES (generation of oscillations H03B)

## Abstract

New and highly stable oscillators are disclosed. Such an oscillator may include a first capacitor electrically connected to a first charging switch and a first discharging switch, a second capacitor electrically connected to a second charging switch and a second discharging switch, a first chopping circuit having a first input electrically connected to the first capacitor and a second input electrically connected to a reference voltage, a second chopping circuit having a first input electrically connected to the second capacitor and a second input electrically connected to the reference voltage, a first comparator having a first input electrically connected to a first and second output of the first chopping circuit, a second comparator having a first input electrically connected to a first and second output of the second chopping circuit, and control circuitry having a first input electrically coupled to an output of the first comparator and a second input electrically connected to an output of the second comparator.

## Claims

### Claim 1

A method of controlling an oscillator, comprising:
comparing a first voltage and a reference voltage in a first comparator to determine a first input offset voltage;
comparing a second voltage with the reference voltage in a second comparator to determine a second input offset voltage;
compensating for a difference between the first input offset voltage of the first comparator and second input offset voltage of the second comparator by connecting a first input of the first comparator to the first voltage and a second input of the first comparator to the reference voltage when a control signal is at a first state, and connecting the first input of the first comparator to the reference voltage and the second input of the first comparator to the first voltage when the control signal is in a second state; and
controlling an oscillation of the oscillator based on the compensated differences in the respective first and second input offset voltages.

### Claim 2 (depends on 1)

A method of claim 1, comprising:
compensating for a difference between the first input offset voltage of the first comparator and second input offset voltage of the second comparator by connecting a first input of the second comparator to the first voltage and a second input of the second comparator to the reference voltage when a second control signal is at the first state, and connecting the first input of the second comparator to the reference voltage and the second input of the second comparator to the first voltage when the second control signal is in the second state.

### Claim 3 (depends on 1)

A method of claim 1, comprising:
creating the control signal based on output signals from the first and second comparators.

### Claim 4 (depends on 2)

A method of claim 2, comprising:
creating the second control signal based on output signals from the first and second comparators.

### Claim 5

An oscillator, comprising:
a capacitor circuit;
a first circuit having a first input electrically connected to the capacitor circuit and a second input electrically connected to a reference voltage, the first circuit including a switching network that connects its first input to its first output and its second input to its second output when a control signal is at a first state, and connects its first input to its second output and its second input to its first output when the control signal is at a second state;
a second circuit having a first input electrically connected to the capacitor circuit and a second input electrically connected to the reference voltage;
a first comparator having a first input and second input electrically connected to the first output and second output of the first circuit; and
a second comparator having a first input and second input electrically connected to a first output and second output of the second circuit.

### Claim 6 (depends on 5)

The oscillator of claim 5, wherein the second circuit further comprises a switching network that:
connects its first input to its first output and its second input to its second output when a second control signal is at a first state; and
connects its first input to its second output and its second input to its first output when the second control signal is at the second state.

### Claim 7 (depends on 6)

The oscillator of claim 6, wherein the control circuitry comprises:
one or more logic gates receiving output signals from the two comparators; and
a latch receiving output signals from the one or more logic gates.

### Claim 8 (depends on 7)

The oscillator of claim 7, wherein the control circuitry further comprises:
a first flip-flop electrically connected to a positive output of the latch and configured to create the control signal that controls the first circuit; and
a second flip-flop electrically connected to a negative output of the latch and configured to create the second control signal that controls the second circuit.

### Claim 9 (depends on 8)

The oscillator of claim 8, wherein the one or more logic gates includes:
a first exclusive-or (XOR) gate having inputs electrically connected to an output of the first comparator and the control signal; and
a second XOR gate electrically having inputs electrically connected to an output of the second comparator and the second control signal.

### Claim 10 (depends on 9)

The oscillator of claim 9, wherein a positive output of the latch controls a second charging switch and a first discharging switch, and a negative output of the latch controls a first charging switch and a second discharging switch.

### Claim 11 (depends on 7)

The oscillator of claim 7, wherein a positive output of the latch controls a second charging switch and a first discharging switch, and a negative output of the latch controls a first charging switch and a second discharging switch.

### Claim 12 (depends on 5)

The oscillator of claim 5, wherein the capacitor circuit has an impedance substantially lower than input impedances of the first and second comparators.

### Claim 13

An oscillator, comprising:
a first comparator and a second comparator;
compensation circuitry electrically connected to the first comparator and the second comparator, the compensation circuitry configured to compensate for a difference in respective input offset voltages of the first comparator and the second comparator, the compensation circuitry including a plurality of choppers receiving respective control signals, the choppers connecting a first input to a first output and a second input to a second output when the control signal is at a first state, and connecting the first input to the second output and the second input to the first output when the control signal is in a second state; and
a circuit configured to control oscillation of the oscillator that is coupled to the first comparator and the second comparator.

### Claim 14 (depends on 13)

The oscillator of claim 13, wherein circuit is also configured to control the compensation circuitry.

### Claim 15 (depends on 14)

The oscillator of claim 14, wherein the compensation circuitry is also coupled to capacitive circuitry and a plurality of switches.

### Claim 16 (depends on 15)

The oscillator of claim 15, wherein the circuit is also coupled to the plurality of switches.