Universal serial bus repeater with improved remote wake capability

Patent metadata

Field	Value
Publication number	US-11803497-B2
Application number	US-202217709812-A
Country	US
Kind code	B2
Filing date	Mar 31, 2022
Priority date	Aug 25, 2021
Publication date	Oct 31, 2023
Grant date	Oct 31, 2023

Abstract

Various configurations of high-speed data communication devices, e.g., repeaters, interfacing between a host and a peripheral, and methods of operating the same, are provided to improve the Remote Wake sequence. Repeaters include circuitry to detect the start of Resume signaling or the end of Resume, following initiation of Remote Wake. In an example, pull-up resistors coupled to upstream differential signal lines and a detection circuit with a current source are controlled to detect the start of Resume signaling. In another example, the upstream-side pull-resistors and an enable signal to an upstream-side transmitter are controlled to detect the end of Resume.

First claim

What is claimed is:

1. A method of operating a repeater in communicating between a first device and a second device through the repeater, the method comprising:
driving data in a first direction from the second device to the first device, including driving to a logic high state a first signal line, of a pair of signal lines between the first device and a first-device-side transceiver of the repeater, and not driving a second signal line of the pair of signal lines;
disabling a resistive element coupled between a power supply voltage and a second signal line of the pair of signal lines;
enabling a detection circuit of the first-device-side transceiver including applying current to the second signal line;
driving, by the first device, the first signal line to a logic high state and the second signal line to a logic low state;
detecting a changed signal level on the second signal line using the detection circuit; and
changing data flow from the first direction to a second direction from the first device to the second device, in response to the detecting.

2. The method of claim 1 , wherein the current applied is in a range of approximately 60 μA to approximately 80 μA.

3. The method of claim 1 , wherein the amount of current applied to the second signal line is set such that the first device detects a logic low state on the second line prior to the first device driving the first signal line to a logic high state and the second signal line to a logic low state.

4. The method of claim 1 , wherein the driving of data in the first direction from the second device to the first device is part of Remote Wake signaling by the second device.

5. The method of claim 4 , wherein the driving, by the first device, the first signal line to a high logic state and the second signal line to a low logic state is part of Resume signaling by the first device; and the detecting of a changed signal level on the second signal line includes detecting the start of the Resume signaling by the first device.

6. A method of operating a repeater in communicating between a first device and a second device through the repeater, the method comprising:
driving data in a first direction from the second device to the first device;
driving a first signal line of a pair of signal lines between the first device and a first-device-side transceiver of the repeater to a logic low state, and driving a second signal line of the pair of signal lines to a logic high state;
disabling a first pull-up resistive element coupled between a power supply voltage and the first signal line and enabling a second pull-up resistive element coupled between the power supply voltage and the second signal line;
changing data flow from the first direction to a second direction from the first device to the second device;
detecting a single-ended zero (SE0) state; and
enabling the first pull-up resistive element and disabling the second pull-up resistive element.

7. The method of claim 6 , wherein driving of the data in the first direction is part of Remote Wake signaling by the second device.

8. The method of claim 6 , wherein the disabling of the first pull-up resistive element and the enabling of the second pull-up resistive element generates a modified K state on the pair of signal lines.

9. The method of claim 8 , wherein, in the modified K state, the second signal line has a lower voltage than in a driven K state.

10. A repeater comprising:
a transceiver including a detection circuit, the detection circuit comprising:
a first current source;
a first comparator having first and second inputs and an output, the first input coupled to a first signal line of a pair of signal lines and to the first current source, the second input configured to receive a reference signal, and the output configured to output a first detection signal;
a second current source; and
a second comparator having first and second inputs and an output, the first input coupled to a second signal line of the pair of signal lines and to the second current source, the second input configured to receive the reference signal, and the output configured to output a second detection signal.

11. The repeater of claim 10 , further comprising:
a first pull-up resistive element selectively couplable to the first signal line; and
a second pull-up resistive element selectively couplable to the second signal line.

12. The repeater of claim 11 , further comprising:
a first switch disposed between the first pull-up resistive element and the first signal line; and
a second switch disposed between the second pull-up resistive element and the second signal line.

13. The repeater of claim 10 , wherein the repeater is a Universal Serial Bus (USB) repeater, and the transceiver is a USB controller.

14. A repeater comprising:
a first assembly including a first pull-up resistor and a first switch, the first assembly coupled to a first signal line of a pair of signal lines, the first switch moveable between an open position in which the first pull-up resistor is disconnected from the first signal line and a closed position in which the first pull-up resistor is connected to the first signal line;
a second assembly including a second pull-up resistor and a second switch, the second assembly coupled to a second signal line of the pair of signal lines, the second switch moveable between an open position in which the second pull-up resistor is disconnected from the second signal line and a closed position in which the second pull-up resistor is connected to the second signal line; and
a transmitter coupled to the first and second signal lines and further including an enable input configured to receive an enable signal based on the positions of the first and second switches.

15. The repeater of claim 14 , wherein, when the first switch is in the closed position, the first pull-up resistor is coupled between the first signal line and a power supply voltage.

16. The repeater of claim 14 , wherein, when the second switch is in the closed position, the second pull-up resistor is coupled between the second signal line and a power supply voltage.

17. The repeater of claim 14 , wherein the first and second switches are configured to be operated to generate a modified K state.

18. The repeater of claim 14 , wherein the repeater is a Universal Serial Bus (USB) repeater.

19. A method of operating a Universal Serial Bus (USB) repeater in communicating between a first device (host) and a second device (peripheral) through the USB repeater, the method comprising:
driving Remote Wake signaling by the second device including driving a K state to exit from a sleep or suspend state;
detecting, using circuitry of the USB repeater, when the first device starts driving Resume signaling; and
changing data flow from a first direction from the second device to the first device to a second direction from the first device to the second device, in response to the detecting.

20. The method of claim 19 , wherein the driving of Resume signaling including driving a K state by the first device.

21. The method of claim 19 , wherein the circuitry comprises at least one comparator and at least one current source.

22. The method of claim 19 , wherein the circuitry comprises a pair of switch-enabled pull-up resistors.

Assignees

• Texas Instruments Inc

Inventors

• Wentroble Mark E
• Vining Suzanne M
• Hariharan Rakesh
• Kamath Anant
• Puttappa Prajwala

Classifications

• G06F13/382 Primary

  using universal interface adapter · CPC title

• G06F9/4413

  Plug-and-play [PnP] · CPC title

• G06F13/4282

  on a serial bus, e.g. I2C bus, SPI bus (on daisy chain buses G06F13/4247) · CPC title

• G06F2213/0042

  Universal serial bus [USB] · CPC title