US 6,441,668 B1 · Digital device with internal differential signal generator

Abstract

A device includes a first input pin, a second input pin, a differential signal generator, and a differential receiver. The first input pin is adapted to receive a first signal. The second input pin is adapted to receive a second signal. The differential signal generator is coupled to the first and second input pins and adapted to receive an enable signal. The differential signal generator is adapted to isolate the second input pin and generate an internal signal based on an inversion of the first signal in response to the enable signal being asserted. The differential receiver has a first input terminal and a second input terminal. The differential receiver is adapted to receive the first signal at the first input terminal and one of the second signal and the internal signal at the second input terminal and generate a differential output signal. A method for generating a differential signal is provided. A first input signal is received at a first input pin of a device. An enable signal is received. A second input pin of the device is isolated based on the enable signal. An internal signal is generated based on an inversion of the first signal. The differential signal is generated based on the first signal and the internal signal.

Claims31

Dependent claims

A device, comprising:

a first input pin adapted to receive a first differential component of a signal;
a second input pin adapted to receive a second differential component of the signal;
a differential signal generator coupled to the first and second input pins and adapted to receive an enable signal, wherein the differential signal generator includes logic adapted to isolate the second input pin and generate an internal differential signal component based on an inversion of the first differential component of the signal in response to the enable signal being asserted;
and
a differential receiver having a first input terminal and a second input terminal and being adapted to receive the first differential component of the signal at the first input terminal and one of the second differential component of the signal and the internal differential signal component at the second input terminal and generate an output signal having a high logic level responsive to a voltage at the first input terminal being greater than a voltage at the second input terminal and a low logic level responsive to the voltage at the first input terminal being less than the voltage at the second input terminal.

2 more elements

A device, comprising:

a first input pin adapted to receive a first signal;
a second input pin adapted to receive a second signal;
a differential receiver having a first input terminal and a second input terminal;
and
a differential signal generator coupled to the first and second input pins and adapted to receive an enable signal, wherein the differential signal generator is adapted to isolate the second input pin and generate an internal signal based on an inversion of the first signal in response to the enable signal being asserted, the differential signal generator comprising:
a first inverter coupled to the first input pin, the internal signal comprising the output of the first inverter;
a first pass gate coupled to the first inverter and the second input terminal of the differential receiver, the first pass gate having a first enable input coupled to receive the enable signal and being adapted to pass the internal signal to the second input terminal in response to the enable signal being asserted;
a second pass gate coupled to the second input pin and the second input terminal of the differential receiver, the second pass gate having a second enable input coupled to receive the enable signal and being adapted to isolate the second input pin from the second input terminal in response to the enable signal being deasserted;
a third pass gate coupled between the first input pin and the first input terminal of the differential receiver, the third pass gate having a third enable input coupled to a voltage source;
a fourth pass gate coupled to the first input pin, the fourth pass gate having a fourth enable input coupled to ground;
and
a second inverter coupled between the second input terminal of the differential receiver and the fourth pass gate,
wherein the differential receiver is further adapted to receive the first signal at the first input terminal and one of the second signal and the internal signal at the second input terminal and generate an output signal having a high logic level responsive to a voltage at the first input terminal being greater than a voltage at the second input terminal and a low logic level responsive to the voltage at the first input terminal being less than the voltage at the second input terminal.

10 more elements

A system, comprising:

a signal generator adapted to provide at least a first signal;
a device coupled to the signal generator, the device comprising:
a first input pin adapted to receive the first signal;
a second input pin;
a differential receiver having a first input terminal and a second input terminal;
and
a differential signal generator coupled to the first and second input pins and adapted to receive an enable signal, wherein the differential signal generator is adapted to isolate the second input pin and generate an internal signal based on an inversion of the first signal in response to the enable signal being asserted, the differential signal generator comprising:
a first inverter coupled to the first input pin, the internal signal comprising the output of the first inverter;
a first pass gate coupled to the first inverter and the second input terminal of the differential receiver, the first pass gate having a first enable input coupled to receive the enable signal and being adapted to pass the internal signal to the second input terminal in response to the enable signal being asserted;
and
a second pass gate coupled to the second input pin and the second input terminal of the differential receiver, the second pass gate having a second enable input coupled to receive the enable signal and being adapted to isolate the second input pin from the second input terminal in response to the enable signal being deasserted;
a third pass gate coupled between the first input pin and the first input terminal of the differential receiver, the third pass gate having a third enable input coupled to a voltage source;
a fourth pass gate coupled to the first input pin, the fourth pass gate having a fourth enable input coupled to ground;
and
a second inverter coupled between the second input terminal of the differential receiver and the fourth pass gate;
wherein the differential receiver is further adapted to receive the first signal at the first input terminal and the internal signal at the second input terminal and generate a differential output signal.

13 more elements

A testing system, comprising:

a signal generator adapted to provide a plurality of test signals including at least a first differential component of a signal;
a device coupled to the signal generator, the device comprising:
a plurality of external pins, at least a subset of the external pins being coupled to the signal generator to receive at least a subset of the test signals, the plurality of external pins including:
a first input pin adapted to receive the first differential component of the signal;
and
a second input pin;
a differential signal generator coupled to the first and second input pins and adapted to receive an enable signal, wherein the differential signal generator includes logic adapted to isolate the second input pin and generate an internal differential signal component based on an inversion of the first differential component of the signal in response to the enable signal being asserted;
and
a differential receiver having a first input terminal and a second input terminal and being adapted to receive the first differential component of the signal at the first input terminal and the internal differential signal component at the second input terminal mid generate an output signal having a high logic level responsive to a voltage at the first input terminal being greater than a voltage at the second input terminal and a low logic level responsive to the voltage at the first input terminal being less than the voltage at the second input terminal.

6 more elements

A testing system, comprising:

a signal generator adapted to provide a plurality of test signals including at least a first signal;
a device coupled to the signal generator, the device comprising:
a plurality of external pins, at least a subset of the external pins being coupled to the signal generator to receive at least a subset of the test signals, the plurality of external pins including:
a first input pin adapted to receive the first signal;
and
a second input pin;
a differential receiver having a first input terminal and a second input terminal;
and
a differential signal generator coupled to the first and second input pins and adapted to receive all enable signal, wherein the differential signal generator is adapted to isolate the second input pin and generate an internal signal based on an inversion of the first signal in response to the enable signal being asserted, the differential signal generator comprising:
a first inverter coupled to the first input pin, the internal signal comprising the output of the first inverter;
a first pass gate coupled to the first inverter and the second input terminal of the differential receiver, the first pass gate having a first enable input coupled to receive the enable signal and being adapted to pass the internal signal to the second input terminal in response to the enable signal being asserted;
and
a second pass gate coupled to the second input pin and the second input terminal of the differential receiver, the second pass gate having a second enable input coupled to receive the enable signal and being adapted to isolate the second input pin from the second input terminal in response to the enable signal being deasserted
a third pass gate coupled between the first input pin and the first input terminal of the differential receiver, the third pass gate having a third enable input coupled to a voltage source;
a fourth pass gate coupled to the first input pin, the fourth pass gate having a fourth enable input coupled to ground;
and
a second inverter coupled between the second input terminal of the differential receiver and the fourth pass gate,
wherein the differential receiver is further adapted to receive the first signal at the first input terminal and the internal signal at the second input terminal and generate an output signal having a high logic level responsive to a voltage at the first input terminal being greater than a voltage at the second input terminal and a low logic level responsive to the voltage at the first input terminal being less than the voltage at the second input terminal.

15 more elements

Dependencies are inferred from the claim text.

Digital device with internal differential signal generator

Life of this patent

Digital device with internal differential signal generator

Life of this patent

Abstract

Claims31