Low power single-rail-input voltage level shifter
First Claim
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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;
a first p-type transistor; and
a first n-type transistor having a drain connected to a drain of the first p-type transistor at a contact point, the first n-type transistor having a source connected to the single-rail input, the first n-type transistor having a gate connected to a reference voltage (VREF), the first p-type transistor having a source connected to the VDDH voltage of the high-voltage domain; and
wherein the voltage-transition circuit includes an input-rising-transition circuit comprising;
a second n-type transistor having a gate connected to the single-rail input, the second n-type transistor having a source connected to a ground voltage, the second n-type transistor having a drain connected to an output contact point, the output contact point being connected to a gate of the first p-type transistor of an input-falling-transition circuit; and
a second p-type transistor having a drain connected to the output contact point, the second p-type transistor having a gate connected to the contact point of the input-falling-transition circuit;
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.
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Abstract
An apparatus includes a single-rail input connected to a low-voltage domain and a voltage-transition circuit connected to the single-rail input. The voltage-transition circuit is configured to convert a voltage of the low-voltage domain received via the single-rail input to a voltage of the high-voltage domain.
12 Citations
8 Claims
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1. A processor comprising a multiplicity of voltage level shifters, each voltage level shifter comprising:
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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; a first p-type transistor; and a first n-type transistor having a drain connected to a drain of the first p-type transistor at a contact point, the first n-type transistor having a source connected to the single-rail input, the first n-type transistor having a gate connected to a reference voltage (VREF), the first p-type transistor having a source connected to the VDDH voltage of the high-voltage domain; and wherein the voltage-transition circuit includes an input-rising-transition circuit comprising; a second n-type transistor having a gate connected to the single-rail input, the second n-type transistor having a source connected to a ground voltage, the second n-type transistor having a drain connected to an output contact point, the output contact point being connected to a gate of the first p-type transistor of an input-falling-transition circuit; and a second p-type transistor having a drain connected to the output contact point, the second p-type transistor having a gate connected to the contact point of the input-falling-transition circuit; 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. - View Dependent Claims (2, 3)
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4. A processor comprising a multiplicity of voltage level shifters, each voltage level shifter comprising:
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a single-rail input connected to a low 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; a first p-type transistor; and a first n-type transistor having a drain connected to a drain of the first p-type transistor at a contact point, the first n-type transistor having a source connected to the single-rail input, the first n-type transistor having a gate connected to a reference voltage (VREF), the first p-type transistor having a source connected to the VDDH voltage of the high-voltage domain; and wherein the voltage-transition circuit includes an input-rising-transition circuit comprising; a second n-type transistor having a gate connected to the single-rail input, the second n-type transistor having a source connected to a ground voltage, the second n-type transistor having a drain connected to an output contact point, the output contact point being connected to a gate of the first p-type transistor of an input-falling-transition circuit; and a second p-type transistor having a drain connected to the output contact point, the second p-type transistor having a gate connected to the contact point of the input-falling-transition circuit; the input-falling-transition circuit triggers a voltage of the output node to change from a VDDH voltage of a high-voltage domain to a ground voltage in response to a voltage of the single-rail-input node changing from a VDDL voltage of a low-voltage domain to the ground voltage, the input-rising-transition circuit triggers a voltage of the output node to change from the ground voltage to the VDDH voltage in response to the voltage of the single-rail-input node changing from the ground voltage to the VDDL voltage; and wherein the reference voltage is a voltage different from VDDH to permit operation in a voltage regime in which 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. - View Dependent Claims (5, 6, 7, 8)
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Specification