# US 2026/0100705 A1 · Encoded differential balanced pam-4 driver structure

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

- Number: US 2026/0100705 A1
- Document ID: US20260100705A1
- Status: Published application
- Kind: A1
- Application number: 18/907,257
- Filed: 2024-10-04
- Published: 2026-04-09
- Earliest claimed: 2024-10-04
- Assignees: QUALCOMM Incorporated
- Applicants: QUALCOMM Incorporated
- Inventors: Chung-Ching LIN; Hongmei LIAO; Sethu LAKSHMANAN
- Web page: https://patentgrep.com/patent/US20260100705A1

## CPC

- H03K 19/00361: {in field effect transistor circuits}
- H04L 25/4917: {using multilevel codes}
- H03K 19/0013: {in field effect transistor circuits}
- H03K 19/018528: {with at least one differential stage}
- H04L 25/0278: {Arrangements for impedance matching}
- H04L 25/0272: {Arrangements for coupling to multiple lines, e.g. for differential transmission}
- H04L 25/028: {Arrangements specific to the transmitter end}
- 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)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

A driver circuit has a logic circuit and a driver subcircuit. The driver subcircuit includes pullup transistors coupled between an output of the driver circuit and a first power rail and pulldown transistors coupled between the output of the driver circuit and a second power rail. The logic circuit includes combinational logic and is configured to turn on a predefined number of transistors during each data transmission interval. The duration of the data transmission interval is configured for an associated data communication channel. The transistors that are turned on may be selected during each data transmission interval based on a value of multibit data to be encoded in signaling state of the data communication channel. The logic circuit may be further configured to turn off transistors in the plurality of transistors that are not selected from the plurality of transistors based on the value of multibit data to be encoded.

## Claims

### Claim 1

A driver circuit, comprising:
a plurality of transistors that includes pullup transistors that are coupled between an output of the driver circuit and a first power rail and pulldown transistors that are coupled between the output of the driver circuit and a second power rail; and
a logic circuit configured to:
turn on a predefined number of transistors during each data transmission interval configured for a data communication channel, the transistors that are turned on being selected during the each data transmission interval from the plurality of transistors based on a value of multibit data to be encoded in signaling state of the data communication channel, and
turn off transistors in the plurality of transistors that are not selected from the plurality of transistors based on the value of multibit data to be encoded.

### Claim 2 (depends on 1)

The driver circuit of claim 1, wherein the multibit data is to be encoded using pulse-amplitude modulation.

### Claim 3 (depends on 2)

The driver circuit of claim 2, wherein the logic circuit is configured to turn on three transistors during each data transmission interval, the three transistors including:
three pullup transistors when the multibit data to be encoded has a first value;
two pullup transistors and one pulldown transistors when the multibit data to be encoded has a second value;
one pullup transistors and two pulldown transistors when the multibit data to be encoded has a third value; and
three pulldown transistors when the multibit data to be encoded has a fourth value.

### Claim 4 (depends on 1)

The driver circuit of claim 1, wherein four different signaling states are defined for the data communication channel.

### Claim 5 (depends on 4)

The driver circuit of claim 4, wherein a combination of pullup transistors and pulldown transistors turned on during each data transmission interval produce voltage levels in the data communication channel that correspond to one of the four different signaling states.

### Claim 6 (depends on 1)

The driver circuit of claim 1, wherein each transistor in the plurality of transistors is configured to contribute a same nominal impedance to the output of the driver circuit when turned on.

### Claim 7 (depends on 1)

The driver circuit of claim 1, wherein the plurality of transistors includes differentially controlled transistor pairs.

### Claim 8 (depends on 1)

The driver circuit of claim 1, wherein the pullup transistors and the pulldown transistors comprise N-type metal-oxide-semiconductor transistors.

### Claim 9 (depends on 1)

The driver circuit of claim 1, wherein the multibit data to be encoded comprises a two-bit number.

### Claim 10 (depends on 9)

The driver circuit of claim 9, wherein the two-bit number is received in a serial datastream.

### Claim 11

A method for transmitting data, comprising:
selecting a predefined number of transistors in a driver circuit to be turned on during a data transmission interval based on a value of multibit data to be encoded in signaling state of a data communication channel;
turning on the predefined number of transistors during the data transmission interval, the transistors that are turned on being selected from a plurality of transistors that includes pullup transistors coupled between the data communication channel and a first power rail and pulldown transistors coupled between the data communication channel and a second power rail; and
turning off transistors in the plurality of transistors that are not selected from the plurality of transistors based on the value of multibit data to be encoded.

### Claim 12 (depends on 11)

The method of claim 11, wherein the multibit data is to be encoded using pulse-amplitude modulation.

### Claim 13 (depends on 12)

The method of claim 12, further comprising turning on three transistors during each data transmission interval, the three transistors including:
three pullup transistors when the multibit data to be encoded has a first value;
two pullup transistors and one pulldown transistors when the multibit data to be encoded has a second value;
one pullup transistors and two pulldown transistors when the multibit data to be encoded has a third value; and
three pulldown transistors when the multibit data to be encoded has a fourth value.

### Claim 14 (depends on 11)

The method of claim 11, wherein four different signaling states are defined for the data communication channel.

### Claim 15 (depends on 14)

The method of claim 14, wherein a combination of pullup transistors and pulldown transistors turned on during each data transmission interval produce voltage levels in the data communication channel that correspond to one of the four different signaling states.

### Claim 16 (depends on 11)

The method of claim 11, wherein each transistor in the plurality of transistors is configured to contribute a same nominal impedance to an output of the driver circuit when turned on.

### Claim 17 (depends on 11)

The method of claim 11, further comprising:
using differential control signals control pairs of transistors in the plurality of transistors.

### Claim 18 (depends on 11)

The method of claim 11, wherein the pullup transistors and the pulldown transistors comprise N-type metal-oxide-semiconductor transistors.

### Claim 19 (depends on 11)

The method of claim 11, wherein the multibit data to be encoded comprises a two-bit number.

### Claim 20 (depends on 19)

The method of claim 19, further comprising:
receiving the two-bit number in a serial datastream.