Low voltage swing pad driver and receiver

• US 20050036562A1
• Filed: 08/25/2004
• Published: 02/17/2005
• Est. Priority Date: 01/24/2002
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Sumant Ranganathan, Tom W. Kwan
• Inventors: Ranganathan, Sumant, Kwan, Tom W.
• Granted Patent: US 7,305,045 B2
• Time in Patent Office: Days
• US Class Current: 375/257
• CPC Class Codes: H04L 27/0002 analog front ends; means for connecting modulators, demodulators or transceivers to a transmission line duplex arrangements H04L5/143

Abstract

Low voltage swing pad driver and receiver. A transmitter portion and a receiver portion are implemented within various devices that communicate using low voltage swing pads communicatively coupled via a trace. The transmitter portion of one device generates a current signal that is pushed/pulled to a low voltage swing pad and is then passed across the trace to another low voltage swing pad. The transmitter portion includes a current driver that outputs the current signal to the low voltage swing pads, and the receiver portion includes a trans-impedance amplifier that transforms the received current signal into a voltage signal. The low voltage swing pad driver and receiver generates a relatively low voltage swing when compared to CMOS full-scale voltage swings thereby significantly reducing the possibility of introducing any noise and/or distortion of data that is communicated via the interface.

Claims

1. A semiconductor system employing low swing pads, the system comprising:

an integrated asynchronous digital subscriber line semiconductor chip; and

wherein the integrated asynchronous digital subscriber line semiconductor chip includes an analog front-end portion;

the analog front-end portion includes a transmitter portion, the transmitter portion being communicatively coupled to a transmitter pad; and

the transmitter portion includes a voltage to current converter that is operable to convert a voltage signal to a current signal and to push/pull the current signal to the transmitter pad.

2. The system of claim 1, wherein:

the current signal generated by the voltage to current converter of the transmitter includes a voltage swing less than approximately plus or minus 100 milli-Volts.

3. The system of claim 1, wherein:

the integrated asynchronous digital subscriber line semiconductor chip further includes a scrambler and a digital level converter;

the scrambler receives a digital input signal and then generates a scrambled digital input signal; and

the digital level converter converts a level of the scrambled digital input signal and provides the level converted scrambled digital input signal to the transmitter portion.

4. The system of claim 3, wherein:

a voltage level of the scrambled digital input signal is approximately 1.8 Volts; and

a voltage level of the level converted scrambled digital input signal that is provided to the transmitter portion is approximately 3.3 Volts.

5. The system of claim 1, wherein:

the transmitter pad communicatively couples to another device via a trace.

6. A semiconductor system employing low swing pads, the system comprising:

an integrated asynchronous digital subscriber line semiconductor chip; and

wherein the integrated asynchronous digital subscriber line semiconductor chip includes an analog front-end portion;

the analog front-end portion includes a receiver portion, the receiver portion being communicatively coupled to a receiver pad; and

the receiver portion includes a current to voltage converter that is operable to receive a current signal at the receiver pad and to transform the received current signal to a voltage signal.

7. The system of claim 6, wherein:

the current signal received by the current to voltage converter of the receiver portion includes a voltage swing less than approximately plus or minus 100 milli-Volts.

8. The system of claim 6, wherein:

the receiver portion includes a digital level converter that is operable to convert the voltage signal from a first level to a second level; and

the first level has a voltage of approximately 3.3 Volts and the second level has a voltage of approximately 1.8 Volts.

9. The system of claim 6, wherein:

the receiver portion includes a trans-impedance amplifier that is operable to receive the current signal and to transform the received current signal to the voltage signal; and

the voltage signal has a magnitude that is approximately 3.3 Volts.

10. The system of claim 6, wherein:

the integrated asynchronous digital subscriber line semiconductor chip further includes a de-scrambler and a digital level converter;

the receiver portion provides the digital signal to the digital level converter;

the digital level converter receives the digital signal and changes a level of the digital signal; and

the de-scrambler receives the voltage level changed digital signal and then generates a de-scrambled digital output signal.

11. A semiconductor system employing at least one low swing pad, the system comprising:

a transmitter portion;

a low swing transmitter pad that is communicatively coupled to the transmitter portion; and

the transmitter portion includes a voltage to current converter that is operable to convert a voltage signal to a current signal and to push/pull the current signal to the low swing transmitter pad.

12. The system of claim 11, wherein:

the current signal generated by the voltage to current converter of the transmitter portion includes a voltage swing less than approximately plus or minus 100 milli-Volts.

13. The system of claim 11, wherein:

the semiconductor system further includes a scrambler and a digital level converter;

the scrambler receives a digital input signal and then generates a scrambled digital input signal; and

the digital level converter converts a level of the scrambled digital input signal and provides the level converted scrambled digital input signal to the transmitter portion.

14. The system of claim 11, wherein:

the transmitter portion further includes a plurality of switches;

the controlling of the plurality of switches controls the pushing and pulling of the current signal to the low swing transmitter pad.

15. The system of claim 11, wherein:

the low swing transmitter pad is communicatively coupled to a low swing receiver pad via a trace.

16. A semiconductor system employing at least one low swing pad, the system comprising:

a receiver portion;

a low swing receiver pad that is communicatively coupled to the receiver portion; and

the receiver portion includes a current to voltage converter that is operable to convert a current signal to a voltage signal and to push/pull the current signal to the low swing receiver pad.

17. The system of claim 16, wherein:

the current signal received by the current to voltage converter of the receiver portion includes a voltage swing less than approximately plus or minus 100 milli-Volts.

18. The system of claim 16, wherein:

the receiver portion includes a digital level converter that is operable to convert the voltage signal from a first level to a second level; and

the first level has a voltage of approximately 3.3 Volts and the second level has a voltage of approximately 1.8 Volts.

19. The system of claim 16, wherein:

the receiver portion includes a trans-impedance amplifier that is operable to receive the current signal and to transform the received current signal to the voltage signal; and

the voltage signal has a magnitude that is approximately 3.3 Volts.

20. The system of claim 16, wherein:

the low swing receiver pad is communicatively coupled to a low swing transmitter pad via a trace.