Patent ID: 6066977
Filing Date: 2000-05-23
Classification: H03K

Abstract:
A circuit for providing programmable voltage output levels in a logic device, the circuit comprising:a pull-up device for driving an output pad with either a first voltage output level or a second voltage output level;a charge pump generating a pumped voltage;a first clamp regulator coupled to the charge pump and the pull-up device, the first clamp regulator receiving a first reference signal, the first clamp regulator generating in response to the first reference signal a first voltage from which the first voltage output level is derived;a second clamp regulator coupled to the pull-up device, the second clamp regulator receiving a second reference signal, the second clamp regulator generating in response to the second reference signal a second voltage from which the second voltage output level is derived; anda passgate multiplexer coupled to each of the first clamp regulator, the second clamp regulator, and the pull-up device, the passgate multiplexer receiving at least one output voltage select signal, the passgate multiplexer causing the pull-up device to drive the output pad with either the first voltage output level or the second voltage output level in response to the at least one output voltage select signal.