Level shift circuit
First Claim
1. A level shift circuit comprising:
- a first logic unit, based on an input signal and a first operation control signal indicating a supply state of a first voltage, generating a first control signal in accordance with the input signal when the level shift circuit is supplied with the first voltage and a second voltage, and including a first transistor which clamps the first control signal at a predetermined first level based on the first operation control signal when the level shift circuit is supplied with the second voltage;
a second logic unit, based on the first control signal and a second operation control signal indicating the supply state of the first voltage, generating a second control signal in accordance with the first control signal when the level shift circuit is supplied with the first and second voltages, and including a second transistor which clamps the second control signal at a predetermined second level based on the second operation control signal when the level shift circuit is supplied with the second voltage; and
a level converter, generating an output signal in response to the first and second control signals.
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Accused Products
Abstract
A level shift circuit determining a logic value while preventing load capacitance from increasing. A voltage detector detects the states of first and second voltages and generates first and second detection signals. A first logic unit generates a first control signal having a level that is in accordance with an input signal or a level of a third voltage in response to the first detection signal. A second logic unit generates a second control signal having a level that is in accordance with the first control signal or a level of the second voltage in response to the second detection signal. A level converter generates an output signal based on the first and second control signals and clamps the output signal at a fixed level when an abnormality occurs in the first voltage.
10 Citations
20 Claims
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1. A level shift circuit comprising:
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a first logic unit, based on an input signal and a first operation control signal indicating a supply state of a first voltage, generating a first control signal in accordance with the input signal when the level shift circuit is supplied with the first voltage and a second voltage, and including a first transistor which clamps the first control signal at a predetermined first level based on the first operation control signal when the level shift circuit is supplied with the second voltage; a second logic unit, based on the first control signal and a second operation control signal indicating the supply state of the first voltage, generating a second control signal in accordance with the first control signal when the level shift circuit is supplied with the first and second voltages, and including a second transistor which clamps the second control signal at a predetermined second level based on the second operation control signal when the level shift circuit is supplied with the second voltage; and a level converter, generating an output signal in response to the first and second control signals. - View Dependent Claims (2, 3)
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4. A level shift circuit comprising:
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a voltage detector detecting a state of a first voltage supplied and a state of a second voltage supplied and generating a first detection signal and a second detection signal; a first logic unit, coupled to the voltage detector, generating a first control signal in response to the first detection signal, wherein the first logic unit generates the first control signal in accordance with an input signal when the level shift circuit is supplied with the first and second voltages, and the first logic unit includes a first transistor which clamps the first control signal at a predetermined first level based on the first detection signal when the level shift circuit is supplied with the second voltage; a second logic unit, coupled to the voltage detector and the first logic unit, generating a second control signal in response to the second detection signal, wherein the second logic unit generates the second control signal in accordance with the first control signal when the level shift circuit is supplied with the first and second voltages, and the second logic unit includes a second transistor which clamps the second control signal at a predetermined second level based on the second detection signal when the level shift circuit is supplied with the second voltage; and a level converter, coupled to the first logic unit and the second logic unit, generating an output signal in response to the first and second control signals. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A level shift circuit for operation by a first voltage, a second voltage that is higher than the first voltage, and a third voltage that is lower than the first and second voltages to generate from an input signal that shifts between the first voltage and the third voltage an output signal that shifts between the second voltage and the third voltage, the level shift circuit comprising:
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a voltage detector detecting whether or not the first voltage is supplied to the level shift circuit and generating first and second detection signals indicating the detection result; a first logic unit, coupled to the voltage detector, generating in response to the first detection signal a first control signal having one of a level that is in accordance with the input signal and a predetermined first level, and including a first transistor which clamps the first control signal at the predetermined first level based on the first detection signal; a second logic unit, coupled to the voltage detector and the first logic unit, generating in response to the second detection signal a second control signal having one of a level that is in accordance with the first control signal and a predetermined second level that differs from the first predetermined level, and including a second transistor which clamps the second control signal at the predetermined second level based on the second detection signal; and a level converter, coupled to the first logic unit and the second logic unit, generating the output signal in response to the first and second control signals, wherein the level converter clamps a logic of the output signal to the first level or the second level when the level shift circuit is not supplied with the first voltage. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification