Patent ID: 7463065
Filing Date: 2008-12-09
Classification: H03K

Abstract:
1. A processor comprising a multiplicity of voltage level shifters, each voltage level shifter comprising: a single-rail input connected to a voltage VDDL of a low-voltage domain; and a voltage-transition circuit connected to the single-rail input, the voltage-transition circuit being configured to convert a voltage of the low-voltage domain received via the single-rail input to a voltage VDDH of a high-voltage domain, wherein the voltage-transition circuit includes an input-falling-transition circuit comprising: wherein the voltage-transition circuit includes an input-rising-transition circuit comprising: wherein the reference voltage is a voltage different from VDDH to permit operation in a voltage regime in which wherein both VDDH and VDDL have a nominal value no greater than about one volt such that the difference between VDDH and VDDL has a comparable magnitude to threshold voltages of said first n-type transistor and said second n-type transistor, the threshold voltage and size of said first n-type transistor being selected to permit the first n-type transistor to turn on in response to a falling voltage and turn off in response to a rising voltage and the size of the second n-type transistor being selected to permit the second n-type transistor to pull the voltage of the output contact point from VDDH to a ground voltage (GND); wherein the threshold voltage of the first n-type transistor is greater than the difference between the reference voltage and VDDL so that the first transistor will turn off in response to a rising voltage, the second transistor has a threshold voltage less than the difference between VDDL and GND so that the second transistor will turn on in response to a rising voltage; wherein the first n-type transistor has a threshold voltage that is less than the difference between VDDL and GND so that the first transistor will turn on in response to a falling voltage and the first transistor is sized to have the strength to pull the voltage of the contact point from VDDH to GND; the second n-type transistor being sized to have the strength to pull the voltage of the output contact point from VDDH to GND; and wherein the n-type transistor of each voltage level shifter is sized such that a change in a voltage of the single-rail input from a ground voltage to a VDDL voltage of the low-voltage domain triggers a voltage of the output contact point to change from a VDDH voltage of the high-voltage domain to the ground voltage.