National Semiconductor Corporation

Larry W DeClue

Tuong Hai Hoang

James Chow

Kenny Wen

Tony S Lo

Luis Sergio Boluna

A low voltage differential signaling (&ldquo;LVDS&rdquo;) line driver includes a pre-emphasis circuit to increase the drive capability of the LVDS line driver. A current source provides a first drive current to a current steering circuit. The pre-emphasis circuit includes a second current source, a current sourcing circuit coupled to the second current source and the current steering circuit and a current sinking circuit coupled to the second current source and the current steering circuit. In this way, first and second drive currents are provided to during the switching of the signal states of an input signal, so that more drive current is supplied to the output of the LVDS line driver circuit. Thus, the time it takes for the current steering circuit to switch the drive current between the first and second directions is decreased.

Low voltage differential signaling driver with pre-emphasis circuit

A circuit for protecting an interface cable driver and the circuitry attached to the driver from electrical overstress damage, such as that which may arise from an electrostatic discharge. The protection circuit includes a sensing element, typically a field oxide transistor, which is used to sense when an EOS transient raises the input/output voltage above the normal operating range. The sensing element is configured to change logic state when the transient reaches a predetermined threshold level. The change in state is used as a feedback path to turn on the interface driver transistor connected to ground and turn off the interface driver transistor connected to the power supply. The interface driver transistor connected to ground then acts to shunt away the transient, preventing damage to the driver and internal circuitry.

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Saratoga, CA, United States of America

Larry W DeClue