LOW-VOLTAGE DIFFERENTIAL SIGNAL DRIVER FOR HIGH-SPEED DIGITAL TRANSMISSION

• US 20070279094A1
• Filed: 05/31/2006
• Published: 12/06/2007
• Est. Priority Date: 05/31/2006
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Jiang, Jian Hong
• Granted Patent: US 7,576,567 B2
• Time in Patent Office: Days
• US Class Current: 326/83
• CPC Class Codes: H03K 19/018528 with at least one differential stage
• CPC Class Codes: H03K 19/094 using field-effect transistors

Abstract

A low-voltage differential signal driver for high-speed digital transmission includes a first converter operable to receive a signal in a first type and convert the signal into a second type, and a cascode current mirror coupled to the first converter. The cascode current mirror provides an impedance level that increases a differential output voltage.

Claims

1. A low-voltage differential signal driver for high-speed digital transmission, comprising:

a first converter operable to receive a signal in a first type and convert the signal into a second type; and

a cascode current mirror coupled to the first converter, the cascode current mirror provides an impedance level that increases a differential output voltage.

2. The driver of claim 1, wherein the cascode current mirror comprises a second converter operable to receive a signal in the second type and convert the signal into the first type.

3. The driver of claim 2, wherein the signal in the first type is a digital signal, the signal in the second type is an analog signal, and the second converter is an analog-to-digital converter.

4. The driver of claim 1, wherein the signal in the first type is a digital signal, the signal in the second type is an analog signal, and the first converter is a digital-to-analog converter.

5. The driver of claim 1, wherein the cascode current mirror comprises a plurality of n-channel metal-oxide semiconductor field effect transistors.

6. The driver of claim 1, wherein the first converter comprises a plurality of p-channel metal-oxide semiconductor field effect transistors.

7. The driver of claim 1, wherein the differential output voltage is greater than 400 mV.

8. The driver of claim 1, wherein the first converter and the cascode current mirror are operable to drive signals at an Ethernet switch.

9. A method for driving a low-voltage differential signal for high-speed digital transmission, comprising:

receiving a signal in a first type;

converting the signal into a second type; and

providing a signal path through a low-voltage differential signal driver, wherein the signal continues through a cascode current mirror, the cascode current mirror providing an impedance level that increases a differential output voltage.

10. The method of claim 9, further comprising:

receiving a signal in the second type; and

converting the signal to the first type.

11. The method of claim 9, wherein the signal in the first type is a digital signal, and the signal in the second type is an analog signal.

12. The method of claim 9, wherein the differential output voltage is greater than 400 mV.

13. The method of claim 9, wherein providing a signal path comprises driving the signal at an Ethernet switch.

14. A system for driving a low-voltage differential signal for high-speed digital transmission, comprising:

means for receiving a signal in a first type;

means for converting the signal into a second type; and

means for providing a signal path through a low-voltage differential signal driver, wherein the signal continues through a cascode current mirror, the cascode current mirror providing an impedance level that increases a differential output voltage.

15. The system of claim 14, further comprising:

means for receiving a signal in the second type; and

means for converting the signal to the first type.

16. The system of claim 14, wherein the signal in the first type is a digital signal, and the signal in the second type is an analog signal.

17. The system of claim 14, wherein the differential output voltage is greater than 400 mV.

18. The system of claim 14, further comprising means for driving the signal at an Ethernet switch.