Bi-directional single-ended transmission systems

Patent metadata

Field	Value
Publication number	US-11528155-B2
Application number	US-202117235392-A
Country	US
Kind code	B2
Filing date	Apr 20, 2021
Priority date	Aug 3, 2020
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

Abstract

Systems for bi-directional single-ended transmission are described. For example, a system may include a receiver with a first differential input terminal and a second differential input terminal, wherein the first differential input terminal is coupled to a first node and the second differential input terminal is coupled to a second node; a transmitter with an output terminal coupled to a third node; a first inductor connected between the first node and the third node; a second inductor connected between the second node and the third node; and a shunt resistor connected between the third node and a ground node. Some implementations include a first inductor with an inductance within twenty percent of 1 microhenry and a capacitance less than a tenth of a picofarad is included in a filter coupling a power supply to transmission line. The first inductor may connect to the transmission line.

First claim

What is claimed is:

1. A system comprising:
a power-over-coax direct current injector;
a coaxial connector;
a first inductor with an inductance within twenty percent of 1 microhenry and a capacitance less than a tenth of a picofarad;
a second inductor with an inductance within twenty percent of 2.2 microhenry and a capacitance less than a half of a picofarad; and
a third inductor with an inductance within twenty percent of 4.7 microhenry and a capacitance less than 2 picofarads, wherein the first inductor, the second inductor and the third inductor are connected in series between the power-over-coax direct current injector and a conductor of the coaxial connector, with the conductor of the coaxial connector connected to the first inductor and the power-over-coax direct current injector connected to the third inductor, wherein the first inductor, the second inductor, and the third inductor in series collectively have an impedance greater than one kiloohm in a frequency range from twenty megahertz to one gigahertz.

2. The system of claim 1 , comprising:
a transmission line connected to the first inductor, wherein the transmission line includes the conductor of the coaxial connector.

3. The system of claim 2 , wherein the transmission line includes a conductor of a coaxial cable.

4. The system of claim 2 , wherein the transmission line includes a conductive trace on a circuit board that connects the first inductor to the conductor of the coaxial connector.

5. The system of claim 1 , comprising:
a circuit board, wherein terminals of the first inductor, the second inductor, and the third inductor are mounted to the circuit board by soldering of the terminals to respective pads on a first layer of the circuit board, and wherein a first pad for the first inductor is connected to the conductor of the coaxial connector, a second pad for the first inductor is connected to a first pad for the second inductor, a second pad for the second inductor is connected to a first pad for the third inductor, and a second pad for the third inductor is connected to the power-over-coax direct current injector.

6. The system of claim 1 , comprising:
a circuit board, wherein the first inductor, the second inductor, and the third inductor are mounted on a first layer of the circuit board; and
a ground plane on a second layer of the circuit board, wherein the ground plane has a ground void under the first inductor, the second inductor, and the third inductor.

7. A system comprising:
a transmission line;
a first inductor with an inductance within twenty percent of 1 microhenry and a capacitance less than a tenth of a picofarad, wherein the first inductor is connected to the transmission line;
a second inductor, wherein the second inductor is connected in series with the first inductor;
a third inductor, wherein the third inductor is connected in series with the second inductor; and
a power source connected to the third inductor, wherein the first inductor, the second inductor, and the third inductor in series collectively have an impedance greater than one kiloohm in a frequency range from twenty megahertz to one gigahertz.

8. The system of claim 7 , wherein the transmission line includes a conductor of a coaxial cable.

9. The system of claim 7 , wherein the transmission line includes a conductive trace on a circuit board that connects the first inductor to a conductor of a coaxial connector.

10. The system of claim 7 , wherein the transmission line includes a conductor of an ethernet cable.

11. The system of claim 7 , wherein the second inductor has an inductance within twenty percent of 2.2 microhenry and a capacitance less than a half of a picofarad.

12. The system of claim 7 , wherein the third inductor has an inductance within twenty percent of 4.7 microhenry and a capacitance less than 2 picofarads.

13. The system of claim 7 , wherein the power source includes a power-over-coax direct current injector.

14. The system of claim 7 , comprising:
a circuit board, wherein the first inductor, the second inductor, and the third inductor are mounted on a first layer of the circuit board; and
a ground plane on a second layer of the circuit board, wherein the ground plane has a ground void under the first inductor, the second inductor, and the third inductor.

15. A system comprising:
a coaxial cable including an inner conductor and an outer conductor;
a first receiver with a first differential input terminal and a second differential input terminal, wherein the first differential input terminal is coupled to a first node, which is coupled to the inner conductor, and the second differential input terminal is coupled to a second node;
a first transmitter with a first differential output terminal and a second differential output terminal, wherein the first differential output terminal is coupled to a third node, which is coupled to the inner conductor, and the second differential output terminal is coupled to a fourth node;
a second transmitter with an output terminal coupled to a fifth node;
a first inductor connected between the first node and the fifth node;
a second inductor connected between the second node and the fifth node;
a first resistor connected between the fifth node and a ground node;
a second receiver with an input terminal coupled to a sixth node;
a third inductor and a second resistor connected in series between the third node and the sixth node; and
three inductors connected in series between the inner conductor and a power-over-coax direct current injector.

16. The system of claim 15 , wherein the three inductors connected in series comprise:
a fourth inductor with an inductance within twenty percent of 1 microhenry and a capacitance less than a tenth of a picofarad.

17. The system of claim 16 , wherein the first transmitter and the first receiver are configured to transfer CoaXPress high-speed downlink signals and the second transmitter and the second receiver are configured to transmit CoaXPress low-speed uplink signals.

18. The system of claim 16 , wherein three inductors connected in series collectively have an impedance greater than one kiloohm in a frequency range from twenty megahertz to one gigahertz.

19. The system of claim 16 , comprising:
a circuit board, wherein the three inductors connected in series are mounted on a first layer of the circuit board; and
a ground plane on a second layer of the circuit board, wherein the ground plane has a ground void under the three inductors connected in series.

Assignees

• Apple Inc

Inventors

• Kim Heegon
• Rajagopal Abhilash
• Bouadjel Samir

Classifications

• H04L12/10 Primary

  Current supply arrangements · CPC title

• H04L12/40045

  Details regarding the feeding of energy to the node from the bus · CPC title