USB-to-VGA converter

• US 20040117538A1
• Filed: 12/11/2002
• Published: 06/17/2004
• Est. Priority Date: 12/11/2002
• Status: Active Grant

• Current Assignee: Kaijet Technology International Ltd., Inc.
• Original Assignee: Magic Control Technology Corporation
• Inventors: Liu, Pei-Chung
• Granted Patent: US 7,203,788 B2
• Time in Patent Office: Days
• US Class Current: 710/315
• CPC Class Codes: G06F 3/14 Digital output to display device ; Cooperation and interconnection of the display device with other functional units
• CPC Class Codes: G09G 5/006 Details of the interface to the display terminal specific for a display terminal using a CRT G09G1/167; using a flat panel G09G3/2096; circuits for interfacing with colour displays G09G5/04

Abstract

A USB-to-VGA converter includes a USB controller connectable to a USB port of a computer for receiving USB based display signals from the computer, a VGA controller connectable to a display device for conveying VGA signals to the display device and a bridge connected between the USB controller and the VGA controller. The bridge receives a bus control command from the USB controller and issues a first-in-first-out control signal to the USB controller to receive the USB based display signals from the USB controller in a first-in-first-out manner. The bridge circuit converts the USB based display signals into corresponding VGA signals and forwarding the VGA signals to the VGA controller, which in turn applies the VGA signals to the display device. No display interface card is required inside the host computer for generation of the VGA signals.

Claims

1. A USB-to-VGA converter comprising:

a USB controller adapted to connect to a USB port of a computer for receiving USB based display signals from the computer, the USB controller issuing a bus control command;

a VGA controller adapted to connect to a display device for conveying VGA signals to the display device; and

a bridge connected between the USB controller and the VGA controller, the bridge receiving the bus control command and issuing a first-in-first-out control signal to the USB controller to receive the USB based display signals from the USB controller in a first-in-first-out manner, the bridge circuit converting the USB based display signals into corresponding VGA signals and forwarding the VGA signals to the VGA controller which in turn applies the VGA signals to the display device.

2. The USB-to-VGA converter as claimed in claim 1, wherein the USB controller comprises a USB socket.

3. The USB-to-VGA converter as claimed in claim 1, wherein the VGA controller comprises a VGA plug.

4. The USB-to-VGA converter as claimed in claim 1, wherein the converter is encased in an adaptor which comprises a USB socket for connection with the USB port of the computer.

5. The USB-to-VGA converter as claimed in claim 4, wherein the adaptor further comprises a VGA plug for connection with the display device.

6. The USB-to-VGA converter as claimed in claim 1, wherein the USB controller, the bridge circuit and the VGA controller are integrated with a display control circuit built inside the display device.

7. The USB-to-VGA converter as claimed in claim 6, wherein the USB controller comprises a USB socket for connection with the USB port of the computer.

8. The USB-to-VGA converter as claimed in claim 6, wherein the VGA controller is directly connected to the display control circuit of the display device.

9. The USB-to-VGA converter as claimed in claim 1, wherein the bridge circuit comprising:

a firmware interface connected to the USB controller for receiving the bus control signal from the USB controller and issuing a DMA control signal, a firmware control signal and control command data;

a first-in-first-out controller connected to the USB controller for issuing the first-in-first-out control signal to the USB controller to receive the USB based display signals from the USB controller in a first-in-first-out manner; and

a display interface conversion device connected to the firmware interface, the first-in-first-out controller and the VGA controller for receiving the DMA control signal, the firmware control signal and the control command data from the firmware interface and being controlled by the first-in-first-out control signal from the first-in-first-out controller to receive the USB based display signals from the USB controller in a first-in-first-out manner, the display interface conversion device converting the USB based display signals into the corresponding VGA signals and forwarding the VGA signals to the VGA controller.

10. The USB-to-VGA converter as claimed in claim 9, wherein the bus control signal from the USB controller to the firmware interface comprises a PIO bus control signal.

11. The USB-to-VGA converter as claimed in claim 9, wherein the firmware interface is connected to the display interface conversion device by a control bus and a data bus.

12. The USB-to-VGA converter as claimed in claim 9, wherein the firmware interface is connected to the display interface conversion device by a DMA address control line, a DMA length control line, a DMA trigger control line, a firmware trigger control line and a data bus.

13. The USB-to-VGA converter as claimed in claim 9, wherein the first-in-first-out controller is connected to the USB controller by a control line and a data bus.

14. The USB-to-VGA converter as claimed in claim 9, wherein the first-in-first-out controller is connected to the display interface conversion device by a control line and a data bus.

15. The USB-to-VGA converter as claimed in claim 9, wherein the VGA signals comprise PCI type VGA display signals.

16. The USB-to-VGA converter as claimed in claim 9, wherein the firmware interface, the first-in-first-out controller and the display interface conversion device are integrated in a single chip integrated circuit.

17. The USB-to-VGA converter as claimed in claim 16, wherein the integrated circuit comprises a field programmable gate array integrated circuit.

18. The USB-to-VGA converter as claimed in claim 16, wherein the integrated circuit comprises an ASIC integrated circuit.