Voltage level shifter
First Claim
1. A voltage level shifter, comprising:
- an input node and an output node;
an input circuit with an input inverter coupled to the input node, wherein the input circuit has a pull-down transistor with a gate electrode coupled to a first node of the input inverter and a first pull-up control transistor with a gate electrode coupled to an opposite second node of the input inverter, and wherein source electrodes of the pull-down transistor and the first pull-up control transistor are coupled to a low voltage reference;
a transient path connectivity limiter with a pull-down transient connectivity limiter transistor and a pull-up transient connectivity limiter transistor, wherein the pull-down transient connectivity limiter transistor has a gate electrode coupled through a first capacitor to the first node of the input inverter and a source electrode of the pull-down transient connectivity limiter transistor is coupled to a drain electrode of the pull-down transistor, and wherein the pull-up transient connectivity limiter transistor has a gate electrode coupled through a second capacitor to the second node of the input inverter and a source electrode of the pull-up transient connectivity limiter transistor is coupled to a drain electrode of the first pull-up control transistor, wherein the transient path connectivity limiter further includes a rapid response pull-down gate control transistor having a source electrode coupled to the gate electrode of the pull-down transient connectivity limiter transistor, a drain electrode coupled to a primary voltage supply node and a gate electrode coupled to a secondary voltage supply node, wherein in operation the primary voltage supply node is at a higher voltage than the secondary voltage supply node; and
an output circuit having a pull-up transistor with source and drain electrodes coupled between the primary voltage supply node and a drain electrode of the pull-down transient connectivity limiter transistor, wherein the drain electrode of the pull-up transistor is coupled to the output node and a gate electrode of the pull-up transistor is coupled to a drain electrode of the pull-up transient connectivity limiter transistor, and wherein the output circuit further includes a second pull-up control transistor having source and drain electrodes coupled between the primary voltage supply and the drain electrode of the pull-up transient connectivity limiter transistor and a gate electrode of the second pull-up control transistor is coupled to the drain electrode of the pull-down transient connectivity limiter transistor.
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Abstract
A voltage level shifter has an input circuit with an inverter coupled to an input node, a pull-down control transistor with a gate coupled to a first node of the inverter, and a pull-up control transistor with a gate coupled to a second node of the inverter. Sources of the pull-down and pull-up control transistors are coupled to a low voltage reference. A transient connectivity limiter (TCL) has pull-down and pull-up transistors. Two control inputs are coupled to respective first and second nodes of the inverter and path inputs are coupled to respective drains of the pull-down and pull-up control transistors. An output circuit has inputs coupled to pull-up and pull-down nodes of the TCL. During a voltage level transition at the input node, the TCL connects the pull-up node to the low voltage reference through the TCL pull-up transistor transitioning from a saturation to a sub-threshold region of operation.
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Citations
17 Claims
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1. A voltage level shifter, comprising:
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an input node and an output node; an input circuit with an input inverter coupled to the input node, wherein the input circuit has a pull-down transistor with a gate electrode coupled to a first node of the input inverter and a first pull-up control transistor with a gate electrode coupled to an opposite second node of the input inverter, and wherein source electrodes of the pull-down transistor and the first pull-up control transistor are coupled to a low voltage reference; a transient path connectivity limiter with a pull-down transient connectivity limiter transistor and a pull-up transient connectivity limiter transistor, wherein the pull-down transient connectivity limiter transistor has a gate electrode coupled through a first capacitor to the first node of the input inverter and a source electrode of the pull-down transient connectivity limiter transistor is coupled to a drain electrode of the pull-down transistor, and wherein the pull-up transient connectivity limiter transistor has a gate electrode coupled through a second capacitor to the second node of the input inverter and a source electrode of the pull-up transient connectivity limiter transistor is coupled to a drain electrode of the first pull-up control transistor, wherein the transient path connectivity limiter further includes a rapid response pull-down gate control transistor having a source electrode coupled to the gate electrode of the pull-down transient connectivity limiter transistor, a drain electrode coupled to a primary voltage supply node and a gate electrode coupled to a secondary voltage supply node, wherein in operation the primary voltage supply node is at a higher voltage than the secondary voltage supply node; and an output circuit having a pull-up transistor with source and drain electrodes coupled between the primary voltage supply node and a drain electrode of the pull-down transient connectivity limiter transistor, wherein the drain electrode of the pull-up transistor is coupled to the output node and a gate electrode of the pull-up transistor is coupled to a drain electrode of the pull-up transient connectivity limiter transistor, and wherein the output circuit further includes a second pull-up control transistor having source and drain electrodes coupled between the primary voltage supply and the drain electrode of the pull-up transient connectivity limiter transistor and a gate electrode of the second pull-up control transistor is coupled to the drain electrode of the pull-down transient connectivity limiter transistor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A voltage level shifter, comprising:
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an input node and an output node; an input circuit with an input inverter coupled to the input node, the input circuit including a pull-down transistor with a gate electrode coupled to a first node of the input inverter and a first pull-up control transistor with a gate electrode coupled to an opposite second node of the input inverter, and wherein source electrodes of the pull-down transistor and the first pull-up control transistor are coupled to a low voltage reference node; a transient path connectivity limiter including a pull-down transient connectivity limiter (TCL) transistor having a gate electrode coupled through a first capacitor to the first node of the input inverter and a source electrode coupled to a drain electrode of the pull-down transistor, a pull-up TCL transistor having a gate electrode coupled through a second capacitor to the second node of the input inverter and a source electrode coupled to a drain electrode of the first pull-up control transistor, two control inputs coupled to the first and second nodes of the input inverter respectively, path input nodes coupled to respective drain electrodes of the pull-down transistor and the first pull-up control transistor, and a rapid response pull-down gate control transistor having a source electrode coupled to the gate electrode of the pull-down TCL transistor, a drain electrode coupled to a primary voltage supply node and a gate electrode coupled to a secondary voltage supply node, wherein in operation the primary voltage supply node is at a higher voltage than the secondary voltage supply node; and an output circuit having a pull-up transistor with source and drain electrodes coupled between the primary voltage supply node and a pull-down node of the transient path connectivity limiter, wherein the drain electrode of the pull-up transistor is coupled to the output node and a gate electrode of the pull-up transistor is coupled to a pull-up control node of the transient path connectivity limiter, and wherein the output circuit further comprises a second pull-up control transistor having source and drain electrodes coupled between the primary voltage supply and the pull-up control node and a gate electrode of the second pull-up control transistor is coupled to the pull-down node, and wherein during a first transition between voltage levels at the input node the transient path connectivity limiter connects the pull-up control node to the low voltage reference node through the pull-up TCL transistor transitioning from a saturation region of operation to a sub-threshold region of operation, and during the first transition between voltage levels at the input node the transient path connectivity limiter further connects the pull-down control node to the low voltage reference node through the pull-down TCL transistor transitioning from a sub-threshold region of operation to a saturation region of operation. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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Specification