# US 2013/0278337 A1 · Differential signal correction circuit

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

- Number: US 2013/0278337 A1
- Document ID: US20130278337A1
- Status: Published application
- Kind: A1
- Application number: 13/790,338
- Filed: 2013-03-08
- Published: 2013-10-24
- Earliest claimed: 2012-04-23
- Assignees: National Taiwan University
- Applicants: National Taiwan University
- Inventors: Shuo-Chun Chou; Hsi-Han Chiang; Chorng-Kuang Wang; Shen-Iuan Liu
- Web page: https://patentgrep.com/patent/US20130278337A1

## CPC

- H03F 1/3282: {Acting on the phase and the amplitude of the input signal}
- H03F 1/3211: {in differential amplifiers}
- H03F 3/19: with semiconductor devices only
- H03F 2200/372: Noise reduction and elimination in amplifier
- H03F 2203/45318: the AAC comprising a cross coupling circuit, e.g. two extra transistors cross coupled
- H03F 2203/45352: the AAC comprising a combination of a plurality of transistors, e.g. Darlington coupled transistors
- H03H 11/32: Networks for transforming balanced signals into unbalanced signals and vice versa, e.g. baluns
- H03F: AMPLIFIERS
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)

## Abstract

A differential signal correction circuit is disclosed. The differential signal correction circuit may comprise a first single-ended-to-differential converter and a second single-ended-to-differential converter. Each one of the two converters may comprise an input port and two output ports. The converters may be configured to perform a first phase correction for a pair of differential signals and output a first output signal and a second output signal. The first output signal is fed back to the first converter through one of the output ports of the first converter, and the second output signal is fed back to the second converter through one of the output ports of the second converter so as to perform phase correction and amplitude correction for the first output signal and the second output signal.

## Claims

### Claim 1

A differential signal correction circuit, comprising:
a first single-ended-to-differential converter having a first input port, a first output port and a second output port, wherein the first output port is coupled with a first output node, the second output port is coupled with a second output node, the first input port is configured to receive a first input signal, the first single-ended-to-differential converter is configured to convert the first input signal into a first current signal and a second current signal, the first current signal is outputted from the first output port, and the second current signal is outputted from the second output port;
a second single-ended-to-differential converter having a second input port, a third output port and a fourth output port, wherein the third output port is coupled with the first output node, the fourth output port is coupled with the second output node, the second input port is configured to receive a second input signal, the second input signal and the first input signal are differential signal pair, the second single-ended-to-differential converter is configured to convert the second input signal into a third current signal and a fourth current signal, the third current signal is outputted from the third output port, and fourth current signal is outputted from the fourth output port;
a first load coupled between the first output node and a first power source, wherein the first load is configured to convert a first output current signal collected from the first current signal and the third current signal at the first output node into a first output voltage signal, and the first output voltage signal is fed back to the first single-ended-to-differential converter for phase and gain correction; and
a second load coupled between the second output node and a second power source, wherein the second load is configured to convert a second output current signal collected from the second current signal and the fourth current signal at the second output node into a second output voltage signal, and the second output voltage signal is fed back to the second single-ended-to-differential converter for phase and gain correction.

### Claim 2 (depends on 1)

The circuit according to claim 1, wherein the first single-ended-to-differential converter includes a first amplifier and a second amplifier, the first amplifier is coupled between the first input port and the first output port, and the second amplifier is coupled between the first output port and the second output port.

### Claim 3 (depends on 2)

The circuit according to claim 2, wherein the second single-ended-to-differential converter includes a third amplifier and a fourth amplifier, the third amplifier is coupled between the third output port and the fourth output port, and the fourth amplifier is coupled between the second input port and the fourth output port.

### Claim 4 (depends on 3)

The circuit according to claim 3, wherein the first amplifier, the second amplifier, the third amplifier and the fourth are devices with three terminals.

### Claim 5 (depends on 4)

The circuit according to claim 4, wherein the first amplifier, the second amplifier, the third amplifier and the fourth are SiGe transistors, hetero-junction bipolar transistors, metal-oxide semiconductor field-effect transistors or bipolar junction transistors.

### Claim 6 (depends on 4)

The circuit according to claim 4, wherein the first amplifier is a first transistor, the second amplifier is a second transistor, a gate of the first transistor and a source of the second transistor are coupled with the first input port, a drain of the first transistor and a gate of the second transistor are coupled with the first output port, a drain of the second transistor is coupled with the second output port, and a source of the first transistor is grounded.

### Claim 7 (depends on 6)

The circuit according to claim 6, wherein the third amplifier is a third transistor, the fourth amplifier is a fourth transistor, a gate of the fourth transistor and a source of the third transistor are coupled with the second input port, a drain of the fourth transistor and a gate of the third transistor are coupled with the fourth output port, a drain of the third transistor is coupled with the third output port, and a source of the third transistor is grounded.

### Claim 8 (depends on 7)

The circuit according to claim 7, wherein an amplification of the first transistor and an amplification of the fourth transistor are equal to a first amplification, an amplification of the second transistor and an amplification of the third transistor are equal to a second amplification, a resistance of the first load is equal to a resistance of the second load, and the second amplification is less than or equal to a sum of the first amplification and a reciprocal of the resistance.

### Claim 9 (depends on 3)

The circuit according to claim 3, wherein the first single-ended-to-differential converter further includes a third load, and the third load is coupled between the first input port and the second amplifier.

### Claim 10 (depends on 9)

The circuit according to claim 9, wherein the second single-ended-to-differential converter further includes a fourth load, and the fourth load is coupled between the second input port and the third amplifier.

### Claim 11 (depends on 10)

The circuit according to claim 10, wherein the third load and the fourth load are active devices or passive devices.

### Claim 12 (depends on 11)

The circuit according to claim 11, wherein the third load and the fourth load are transistors, resistors, capacitors, inductances or transmission lines.

### Claim 13 (depends on 1)

The circuit according to claim 1, wherein the first load and the second load are active devices or passive devices.

### Claim 14 (depends on 13)

The circuit according to claim 13, wherein the first load and the second load are transistors, resistors, capacitors, inductances, or transmission lines.

### Claim 15

A differential signal correction circuit, comprising:
a first transistor, wherein a gate of the first transistor is configured to receive a first input signal, and a source of the first transistor is grounded;
a second transistor, wherein a source of the second transistor is coupled with the gate of the first transistor, and a gate of the second transistor is coupled with a drain of the first transistor;
a third transistor, wherein a source of the third transistor is configured to receive a second input signal, the first input signal and the second input signal are differential signal pair, a drain of the third transistor is coupled with the drain of the first transistor, and a gate of the third transistor is coupled with a drain of the second transistor;
a fourth transistor, wherein a gate of the fourth transistor is coupled with the source of the third transistor, a drain of the fourth transistor is coupled with the gate of the third transistor, and a source of the fourth transistor is grounded;
a first load coupled between the drain of the first transistor and a first power source; and
a second load coupled between the drain of the fourth transistor and a second power source;
wherein the first input signal and the second input signal are phase corrected by the first transistor, the second transistor, the third transistor and the fourth transistor, a first output current signal is collected from a coupled node of the drain of the first transistor and the gate of the second transistor, a second output current signal is collected from a coupled node of the gate of the third transistor and the drain of the fourth transistor, the first output current signal is converted into a first output voltage signal by the first load, the second output current signal is converted into a second output voltage signal by the second load, the first output voltage signal is fed back to the first transistor and the second transistor via the coupled node of the drain of the first transistor and the gate of the second transistor, the second output voltage signal is fed back to the third transistor and the fourth transistor via the coupled node of the gate of the third transistor and the drain of the fourth transistor for gain and secondary phase correction.

### Claim 16 (depends on 15)

The circuit according to claim 15, wherein an amplification of the first transistor and an amplification of the fourth transistor are equal to a first amplification, an amplification of the second transistor and an amplification of the third transistor are equal to a second amplification, a resistance of the first load is equal to a resistance of the second load, and the second amplification is less than or equal to a sum of the first amplification and a reciprocal of the resistance.

### Claim 17 (depends on 16)

The circuit according to claim 16, wherein the first load and the second load are active devices or passive devices.

### Claim 18 (depends on 17)

The circuit according to claim 17, wherein the first load and the second load are transistors, resistors, capacitors, inductances or transmission lines.

### Claim 19 (depends on 16)

The circuit according to claim 16, further comprising a third load coupled between the gate of the first transistor and the source of the second transistor.

### Claim 20 (depends on 19)

The circuit according to claim 19, further comprising a fourth load coupled between the gate of the fourth transistor and the source of the third transistor.

### Claim 21 (depends on 20)

The circuit according to claim 20, wherein the third load and the fourth load are active devices or passive devices.

### Claim 22 (depends on 21)

The circuit according to claim 21, wherein the third load and the fourth load are transistors, resistors, capacitors, inductances or transmission lines.