Chip-to-chip digital transmission circuit delivering power over signal lines

• US 7,348,805 B2
• Filed: 05/02/2006
• Issued: 03/25/2008
• Est. Priority Date: 05/02/2006
• Status: Expired due to Fees

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Gravrok, Roger J., Pease, David L., Csongradi, William J. Jr., Cannon, Todd A., Schlichting, Ryan J.
• Primary Examiner(s): Tan; Vibol
• Assistant Examiner(s): LO, CHRISTOPHER KWOK YEUNG
• Application Number:
  US11/381,135
• Publication Number:
  US 20070257823A1
• Time in Patent Office: 693 Days
• Field of Search: 326/112, 326/115, 326/121, 326/127, 326/82, 326/83, 326/86, 326/26, 326/30, 327/108, 327/109
• US Class Current: 326/86
• CPC Class Codes: H04L 25/02 Details ; arrangements for supplying electrical power along data transmission lines systems for transmitting signals via power distribution lines H04B3/54
• CPC Class Codes: H04L 25/0272 Arrangements for coupling to multiple lines, e.g. for differential transmission

Abstract

A chip-to-chip digital transmission circuit includes a differential driver portion, a pair of differential signal transmission lines connected to the driver portion, and a receiver portion connected to the transmission lines, an output node of which reproduces a digital bit stream originally presented to a driver side input node, wherein the transmission lines carry both transmitted signal information and DC power for the receiver portion. The driver portion is configured to adjust both the transmitted signal magnitude and the DC power delivered to the receiver portion.

Claims

1. A chip-to-chip digital transmission circuit, comprising:

a differential driver portion, comprising a pull up device configured between a voltage supply rail and a pair of driver side load resistors, said driver side load resistors connected to opposing legs of the differential driver portion, a pair of driver pull down devices connected to the opposing legs of the differential driver portion, wherein gate terminals of the pair of driver pull down devices comprise the driver side input node, and a first adjustable current source configured to provide current through a conducting one of the opposing legs of the driver portion;

a pair of differential signal transmission lines connected to the driver portion;

a receiver portion connected to the transmission lines, an output node of which substantially reproduces a digital bit stream originally presented to a driver side input node, wherein the receiver portion further comprises a pair of impedance matching load resistors connected at first ends thereof to a corresponding one of the differential signal transmission lines, said pair of impedance matching load resistors connected to one another at second ends thereof so as to define a common mode voltage node, a pair of common mode voltage load resistors coupled at first ends thereof to the common mode voltage node, and at second ends thereof, to a pair of receiver pull down devices in opposing legs of the receiver portion, the pair of receiver pull down devices having gate terminals capacitively coupled to the differential signal transmission lines, and a second adjustable current source configured to provide current through a conducting one of the opposing legs of the driver portion;

wherein the transmission lines carry both transmitted signal information and DC power for the receiver portion, and wherein the voltage of the common mode voltage node is adjustably controlled by the pull up device of the differential driver portion.

2. The transmission circuit of claim 1, wherein the amount of power consumed by the driver portion in transmitting the bit stream is adjustably controlled such that a portion of the adjustable power is delivered to the receiver.

3. The transmission circuit of claim 1, wherein a differential voltage swing of the transmitted signal information is adjustably controlled by the driver portion.

4. The transmission circuit of claim 1, wherein the voltage of the common mode voltage node is also adjustably controlled by the first adjustable current source of the differential driver portion.

5. The transmission circuit of claim 1, wherein a differential voltage swing of the transmitted signal information is adjustably controlled by the first adjustable current source of the differential driver portion.

6. The transmission circuit of claim 1, wherein the pair of driver pair of pull down devices have a greater strength that the pair of receiver pull down devices.

7. The transmission circuit of claim 1, wherein the first adjustable current source of the differential driver portion provides a larger amount of current than the second adjustable current source of the receiver portion.

8. A bi-directional, chip-to-chip digital transmission circuit, comprising;

a first differential driver portion of a first chip domain;

a pair of differential signal transmission lines connected to the first differential driver portion, the differential signal transmission lines coupling the first chip domain to a second chip domain;

a first receiver portion of the second chip domain, connected to the transmission lines;

a second differential driver portion of the second chip domain, connected to the transmission lines, each of the first and second driver portions further comprising a pull up device configured between a voltage supply rail and a pair of driver side load resistors, said driver side load resistors connected to opposing legs of the differential driver portion, a pair of driver pull down devices connected to the opposing legs of the differential driver portion, wherein gate terminals of the pair of driver pull down devices comprise the driver side input node, and a driver side adjustable current source configured to provide current through a conducting one of the opposing legs of the driver portion; and

a second receiver portion of the first chip domain, connected to the transmission lines, each of the first and second receiver portions further comprising a pair of impedance matching load resistors connected at first ends thereof to a corresponding one of the differential signal transmission lines, said pair of impedance matching load resistors connected to one another at second ends thereof so as to define a common mode voltage node, a pair of common mode voltage load resistors coupled at first ends thereof to the common mode voltage node, and at second ends thereof, to a pair of receiver pull down devices in opposing legs of the receiver portion, the pair of receiver pull down devices having gate terminals capacitively coupled to the differential signal transmission lines, and a receiver side adjustable current source configured to provide current through a conducting one of the opposing legs of the driver portion;

wherein the transmission lines are configured to carry, in both directions, transmitted signal information from one of the chip domains and DC power for the receiver portion of the other of the chip domains, and wherein the voltage of the common mode voltage node is adjustably controlled by the pull up device of the differential driver portion.

9. The bi-directional transmission circuit of claim 8, wherein the amount of power consumed by the first and second driver portions in transmitting a digital bit stream is adjustably controlled.

10. The bi-directional transmission circuit of claim 8, wherein a differential voltage swing of transmitted signal information is adjustably controlled by the first and second driver portions.

11. The bi-directional transmission circuit of claim 8, wherein the voltage of the common mode voltage node is also adjustably controlled by the adjustable current source of the differential driver portion.

12. The bi-directional transmission circuit of claim 8, wherein a differential voltage swing of the transmitted signal information is adjustably controlled by the adjustable current source of the differential driver portion.

13. The bi-directional transmission circuit of claim 8, wherein the pair of driver pair of pull down devices have a greater strength that the pair of receiver pull down devices.

14. The bi-directional transmission circuit of claim 8, wherein the adjustable current source of the differential driver portion provides a larger amount of current than the adjustable current source of the receiver portion.