Overvoltage protection circuit
AssigneeXilinx, Inc.
InventorBruno Miguel Vaz
Life of this patent
Estimating the term…
Abstract
In an example, an input buffer includes: first buffer circuit having an output, a first voltage control node, and a second voltage control node; a first transistor having a gate coupled to the output of the first buffer circuit, a drain, and a source; a second buffer circuit having an input coupled to a reference voltage and an output coupled to the source of the first transistor; and a first current source having a reference output coupled to the drain of the first transistor, a first output coupled to the first voltage control node of the first buffer circuit, and a second output coupled to the second voltage control node of the second buffer circuit.
Claims20
An input buffer, comprising:
- first buffer circuit having an output, a first voltage control node, and a second voltage control node;
- a first transistor having a gate coupled to the output of the first buffer circuit, a drain, and a source;
- a second buffer circuit having an input coupled to a reference voltage and an output coupled to the source of the first transistor;
- and
- a first current source having a reference output coupled to the drain of the first transistor, a first output coupled to the first voltage control node of the first buffer circuit, and a second output coupled to the second voltage control node of the first buffer circuit.
An analog-to-digital converter (ADC), comprising:
- ADC and control circuitry configured to sample an analog signal and generate a digital signal;
- and
- an input buffer configured to receive a radio frequency (RF) signal and generate the analog signal, the input buffer including:
- a first buffer circuit having an output, a first voltage control node, and a second voltage control node;
- a first transistor having a gate coupled to the output of the first buffer circuit, a drain, and a source;
- a second buffer circuit having an input coupled to a reference voltage and an output coupled to the source of the first transistor;
- and
- a first current source having a reference output coupled to the drain of the first transistor, a first output coupled to the first voltage control node of the first buffer circuit, and a second output coupled to the second voltage control node of the first buffer circuit.
A method of buffering a radio frequency (RF) signal, comprising:
- generating, using a first buffer circuit, an output voltage in response to the RF signal;
- detecting, using a first transistor coupled to receive the output voltage, that the output voltage exceeds a reference voltage and drawing a first reference current from a first current source;
- injecting a first current generated by the first current source based on the first reference current to a first control node of the first buffer circuit;
- and
- injecting a second current generated by the first current source based on the first reference current to a second control node of the first buffer circuit.
Dependencies are inferred from the claim text.