Dynamic Level Shifter
First Claim
1. A circuit comprising:
- a precharge circuit coupled to receive a clock signal, wherein the precharge circuit is configured to precharge an evaluation node to a first logic level during a first phase of the clock signal;
a pull-down circuit having an input node coupled to receive an input signal, wherein the pull-down circuit is configured to, during a second phase of the clock signal, provide a pull-down path between the evaluation and a ground node responsive to receiving the input signal at the first logic level; and
a keeper circuit, wherein the keeper circuit is configured to, during the second phase of the clock signal, hold the evaluation node at the first logic level responsive to the input node receiving the input signal at a second logic level;
wherein the first logic level, on the input node, is referenced to a first supply voltage, and wherein the first logic level, on the evaluation node, is referenced to a second supply voltage.
1 Assignment
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Accused Products
Abstract
A dynamic level shifter is disclosed. In one embodiment, a dynamic level shifter circuit may receive an input signal referenced to a first voltage of a first power domain, and may output a corresponding signal referenced to a second voltage into a second power domain. The dynamic level shifter circuit may include an evaluation node that is precharged during a first phase (e.g., the low portion) of a clock signal. During the second phase (e.g., the high portion) of the clock signal, the evaluation node may be either pulled low or high, depending on the state of the input signal. A corresponding output signal, based on the evaluated level on the evaluation node, may be output into the second power domain.
14 Citations
25 Claims
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1. A circuit comprising:
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a precharge circuit coupled to receive a clock signal, wherein the precharge circuit is configured to precharge an evaluation node to a first logic level during a first phase of the clock signal; a pull-down circuit having an input node coupled to receive an input signal, wherein the pull-down circuit is configured to, during a second phase of the clock signal, provide a pull-down path between the evaluation and a ground node responsive to receiving the input signal at the first logic level; and a keeper circuit, wherein the keeper circuit is configured to, during the second phase of the clock signal, hold the evaluation node at the first logic level responsive to the input node receiving the input signal at a second logic level; wherein the first logic level, on the input node, is referenced to a first supply voltage, and wherein the first logic level, on the evaluation node, is referenced to a second supply voltage. - View Dependent Claims (2, 3, 4, 5)
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6. A level shifter comprising:
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an evaluation node; an inverter having an input coupled to the evaluation node; a first transistor having a gate terminal coupled to an output of the inverter, a source terminal coupled to a first power supply voltage having a first magnitude during use, and a drain terminal; a second transistor having a source terminal coupled to the drain terminal of the first transistor, and a drain terminal coupled to the evaluation node; a precharge transistor having a source terminal coupled to the first power supply voltage, a drain terminal coupled to the evaluation node, and a gate terminal coupled to receive a clock signal, wherein the precharge transistor is configured to precharge the evaluation node to a first logic level during a first phase of the clock signal; and an evaluation circuit coupled between the evaluation node and the ground node, wherein the evaluation circuit is configured to drive the evaluation node to a second logic level if activated during the second phase of the clock signal, wherein the evaluation circuit is coupled to an input node coupled to receive an input referenced to a second power supply voltage having a second magnitude during use, the second magnitude different from the first magnitude. - View Dependent Claims (7, 8, 9, 10)
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11. An integrated circuit comprising:
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a processor core coupled to receive a first supply voltage; a memory coupled to receive a second supply voltage; and a static level shifter coupled to receive an input clock signal conveyed by the core, wherein the input clock signal is referenced to the first supply voltage, and wherein the static level shifter is configured to provide an output clock signal to the memory, wherein the output clock signal is referenced to the second supply voltage; wherein the memory includes a plurality of dynamic level shifter circuits each coupled to receive a corresponding signal from the processor core, wherein each of the dynamic level shifter circuits includes; a transfer node; a precharge circuit coupled to receive the output clock signal and configured to precharge the transfer node when the output clock signal is at a logic low level; an evaluation circuit having an input node coupled to receive a corresponding one of a plurality of input signals from the processor core, wherein the evaluation circuit is configured to, when active, provide a pull-down path between the transfer node and a ground node; a keeper circuit coupled between the evaluation node and the second voltage node, wherein the keeper circuit is configured to, when active, provide a keeper path between the transfer node and the second voltage node; wherein the input signal is referenced to the first supply voltage, and wherein a signal on the transfer node is referenced to the second supply voltage. - View Dependent Claims (12, 13, 14, 15)
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16. A method comprising:
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a precharge circuit precharging an evaluation node of a dynamic level shifter circuit responsive to receiving a first clock signal at a logic low level on its respective gate terminal; a pull-down circuit pulling the evaluation node to a logic low level when at least the first clock signal and an input signal are both at a logic high level; a keeper circuit pulling the evaluation node to a logic high level when at least the evaluation node is at a logic high level; and the dynamic level shifter circuit providing an output signal at a logic low signal when the evaluation node is at a logic high level and providing the output signal at a logic high level when the evaluation node is at a logic low level; wherein the input signal is referenced to a first supply voltage, and wherein the output signal and a signal on the evaluation node are each referenced to a second supply voltage. - View Dependent Claims (17, 18, 19, 20)
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21. A dynamic level shifter comprising:
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a first p-channel metal oxide semiconductor (PMOS) transistor coupled between an evaluation node and a first supply voltage node, wherein the first PMOS transistor is configured to be activated responsive to receiving a first clock signal as a logic low on a respective gate terminal; a first inverter having an input coupled to the evaluation node; a second PMOS transistor having a gate terminal coupled to an output of the inverter, the second PMOS transistor being further coupled to the first supply voltage node; a third PMOS transistor coupled between the second PMOS transistor and the evaluation node; a first n-channel metal oxide semiconductor (NMOS) transistor coupled to a return node and having a respective gate terminal coupled to receive the first clock signal, wherein the first NMOS transistor is configured to be activated responsive to receiving the first clock signal as a logic high on its respective gate terminal; and a second NMOS transistor coupled to the evaluation node, the second NMOS transistor having a respective gate terminal coupled to receive an input signal, wherein the second NMOS transistor is configured to be activated responsive to receiving the input signal as a logic high; wherein the first clock signal and a signal on the evaluation node are each referenced to a first supply voltage present on the first supply voltage node, and wherein the input signal is referenced to a second supply voltage having a magnitude less than the first supply voltage. - View Dependent Claims (22, 23, 24, 25)
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Specification