# US 10,312,869 B2 · Methods and devices relating to high gain amplifiers

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- Number: US 10,312,869 B2
- Document ID: US10312869B2
- Status: Granted
- Kind: B2
- Application number: 15/630,582
- Filed: 2017-06-22
- Published: 2017-12-28
- Granted: 2019-06-04
- Earliest claimed: 2016-06-24
- Assignees: The Royal Institution for the Advancement of Learning/Mcgill University
- Applicants: The Royal Institution for the Advancement of Learning/Mcgill University
- Inventors: Gordon Roberts; Ming Yang
- Web page: https://patentgrep.com/patent/US10312869B2

## CPC

- H03F 3/04: with semiconductor devices only
- H03F 1/0205: {in transistor amplifiers}
- H03F 1/083: {in transistor amplifiers (H03F1/10 - H03F1/22 take precedence)}
- H03F 3/45183: {Long tailed pairs (H03F3/4521, H03F3/45237 take precedence)}
- H03F 3/45475: {using IC blocks as the active amplifying circuit}
- H03F 2200/117: A coil being coupled in a feedback path of an amplifier stage
- H03F 2200/153: Feedback used to stabilise the amplifier
- H03F 2203/45138: Two or more differential amplifiers in IC-block form are combined, e.g. measuring amplifiers
- H03H 11/0422: {using transconductance amplifiers, e.g. gmC filters}
- H03F: AMPLIFIERS
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)

## Abstract

There is described herein methods and devices for high DC gain closed loop operation amplifiers exploiting cascaded low gain stages and a controller-based compensation circuit for stability.

## Claims

### Claim 1

An amplifier circuit comprising:
a plurality of cascaded circuit elements arranged in a closed-loop topology, the closed-loop topology comprising a plurality of gain stages defined by the cascaded circuit elements; and
a controller provided in the closed-loop topology, the plurality of cascaded circuit elements and the controller together implementing an open-loop transfer function composed of an amplifier function and a remainder function, the gain stages corresponding to the amplifier function and the controller configured to implement the remainder function.

### Claim 2 (depends on 1)

The amplifier circuit of claim 1, wherein the closed-loop topology defines one of an operational transconductance amplifier and an operational amplifier.

### Claim 3 (depends on 2)

The amplifier circuit of claim 2, wherein the plurality of gain stages each comprise at least one undamped integrator.

### Claim 4 (depends on 3)

The amplifier circuit of claim 3, wherein the at least one integrator is a Miller-C integrator.

### Claim 5 (depends on 3)

The amplifier circuit of claim 3, wherein the at least one integrator is a two-input Miller-C integrator.

### Claim 6 (depends on 1)

The amplifier circuit of claim 1, wherein the remainder function is a pole-zero canonical type transfer function.

### Claim 7 (depends on 1)

The amplifier circuit of claim 1, wherein the controller is composed of a plurality of controller elements, wherein the controller elements are interleaved with the cascaded circuit elements in the closed-loop topology.

### Claim 8 (depends on 1)

The amplifier circuit of claim 1, wherein the amplifier circuit is programmable to operate on multiple orders and realize a plurality of closed-loop transfer functions.

### Claim 9 (depends on 1)

The amplifier circuit of claim 1, wherein the amplifier circuit is realized using a canonical state-space formulation.

### Claim 10 (depends on 1)

The amplifier circuit of claim 1, wherein at least one of bandwidth, impedance, and dynamic range is scaled using a scaling factor.

### Claim 11

A method for providing an amplifier circuit, the method comprising:
selecting a closed-loop transfer function for the amplifier circuit, the closed-loop transfer function having a corresponding open-loop transfer function composed of an amplifier function and a remainder function;
determining a closed-loop topology for a plurality of cascaded circuit elements and a controller, the cascaded circuit elements defining a plurality of gain stages that correspond to the amplifier function of the open-loop transfer function; and
configuring the controller to implement the remainder function of the open-loop transfer function.

### Claim 12 (depends on 11)

The method of claim 11, wherein the closed-loop topology defines one of an operational transconductance amplifier and an amplifier.

### Claim 13 (depends on 12)

The method of claim 12, wherein the plurality of gain stages each comprise at least one undamped integrator.

### Claim 14 (depends on 13)

The method of claim 13, wherein the at least one integrator is a Miller-C integrator.

### Claim 15 (depends on 13)

The method of claim 13, wherein the at least one integrator is a two-input Miller-C integrator.

### Claim 16 (depends on 11)

The method of claim 11, wherein the remainder function is a pole-zero canonical type transfer function.

### Claim 17 (depends on 11)

The method of claim 11, wherein the controller is composed of a plurality of controller elements, wherein the controller elements are interleaved with the cascaded circuit elements in the closed-loop topology.

### Claim 18 (depends on 11)

The method of claim 11, further comprising programming the amplifier circuit to operate on multiple orders and to realize a plurality of closed-loop transfer functions.

### Claim 19 (depends on 11)

The method of claim 11, further comprising using a canonical state-space formulation to realize the amplifier circuit.

### Claim 20 (depends on 11)

The method of claim 11, further comprising scaling at least one of bandwidth, impedance, and dynamic range using a scaling factor.