Gould Inc.

Kelvin K Hsueh

Brian R Kauffmann

Gerardus F Riebeek

In a high-voltage output buffer, a self-adjusting bias generator is provided which is capable of automatically adjusting the applied bias voltages in the output buffer so as to enhance the output buffer performance. Under normal or high supply voltage conditions, the bias generator provides a first set of bias voltages to the series-connected transistors in the output buffer. Under low supply voltage conditions, the bias generator provides a second set of bias voltages to the various series-connected transistors.

CMOS self-adjusting bias generator for high voltage drivers

A highly stable high-voltage output buffer is provided which may be manufactured using standard CMOS technology. As part of the invention, the effects of voltage drift at one or more of the nodes formed between series connected P or N-channel MOSFET devices are generally reduced or eliminated. The present invention includes compensation circuitry which reduces the effects of parasitic coupling within the MOSFET devices, and which serves to compensate for any voltage drift which may occur at the nodes between series connected devices. In addition, the present invention provides a method and apparatus for increasing the current sourcing capability of a CMOS high-voltage output buffer, even under low supply V.sub.vf conditions, without necessarily increasing the size of the output device. Furthermore, the present invention provides a method and apparatus for reducing the effects of coupling along a shared bias line between a plurality of high-voltage output buffers in accordance with the present invention.

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Pocatello, ID, United States of America

Kelvin K Hsueh