Circuitry to provide a low power input buffer
OwnerMichael J. McManusinventor
Life of this patent
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Abstract
Input buffer circuitry that prevents high voltage output from high voltage circuitry from being applied to connected low voltage circuitry. An input of the input buffer circuitry receives signals from the high voltage circuitry. Pinch-off circuitry receives the input signals and prevents voltage above a threshold voltage from being applied to an output of the pinch-off circuitry. Boost circuitry controls the threshold voltage of the pinch-off circuitry and pull-up circuitry draws voltage from the output of the pinch-off circuitry to regulate the control by the booster circuitry.
Claims38
An input buffer circuitry that connects low power circuitry to high power circuitry wherein said low power circuitry operates at a first voltage and said high power circuitry operates at a second voltage that is greater than said first voltage comprising:
- an input that receives signals at said second voltage from said high power circuitry;
- pinch-off circuitry that receives said signals and prevents voltage above a threshold voltage from being applied to an output of said pinch-off circuitry wherein said pinch-off circuitry includes a first pinch-off transistor and a second pinch-off transistor and wherein said first pinch-off transistor and said second pinch-off transistor are n-channel transistors;
- boost circuitry that controls said threshold voltage of said pinch-off circuitry;
- and
- pull-up circuitry that connects to said output of said pinch-off circuitry to draw current from said output of said pinch-off circuitry.
An input buffer circuit connecting a first circuit to a second circuit, wherein said first circuit operates at a first voltage and said second circuit operates at a second voltage that is greater than said first voltage, the input buffer circuit comprising:
- pinch-off circuitry configured to receive said second voltage from said second circuit and to prevent a voltage above a threshold voltage from being applied to an output of said pinch-off circuitry, wherein said pinch-off circuitry comprises both a first pinch-off transistor and a second pinch-off transistor, and wherein said first pinch-off transistor and said second pinch-off transistor are N-channel transistors;
- and
- boost circuitry, including a transistor, configured to receive a supply voltage and to apply a source voltage to said pinch-off circuitry in response to said supply voltage, wherein said pinch-off circuitry is further configured to apply a voltage corresponding to said first voltage to said output of said pinch-off circuitry in response to said source voltage.
A method for providing a buffer between a first circuit operating at a first voltage and a second circuit operating at a second voltage, the method comprising:
- receiving a signal from said second circuit, wherein the signal has said second voltage;
- receiving a supply voltage and then applying a source voltage to pinch-off circuitry in response to said supply voltage, wherein said pinch-off circuitry is configured to prevent a voltage above a threshold voltage from being applied from an output of said pinch-off circuitry to said first circuit;
- and
- applying a voltage corresponding to said first voltage to said output of said pinch-off circuitry in response to the source voltage.
Dependencies are inferred from the claim text.