High-voltage-tolerant feedback coupled I/O buffer
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorKer-Min Chen
Life of this patent
Estimating the term…
Abstract
An input/output buffer comprises an input/output pad operable to receive an input signal and transmit an output signal, an output driver coupled to the input/output pad, an input path comprising an input transistor coupled to the input/output pad operable to pass an input signal received at the input/output pad to a core circuit coupled to the input/output buffer. The input/output buffer further comprises an output path coupled to the output driver operable to pass an output signal received from the core circuit to the input/output pad, a feedback path coupled to the input transistor in the input path and operable to cut off the output path during input mode, and a biasing circuit coupled to selected transistors in the output path, feedback path and output driver.
Claims20
An input/output buffer, comprising:
- an input/output pad operable to receive an input signal and transmit an output signal;
- an output driver coupled to the input/output pad;
- an input path comprising an input transistor coupled to the input/output pad operable to pass an input signal received at the input/output pad to a core circuit coupled to the input/output buffer;
- an output path coupled to the output driver operable to pass an output signal received from the core circuit to the input/output pad;
- a feedback path coupled to the input transistor in the input path and operable to cut off the output path during input mode;
- and
- a biasing circuit coupled to selected transistors in the output path, feedback path and output driver.
An integrated circuit having at least one input/output circuit, comprising:
- an output driver coupled to an input/output pad and operable to provide an output signal to the input/output pad;
- an input path comprising an input transistor coupled to the input/output pad operable to receive an input signal received at the input/output pad;
- an output path coupled to the output driver operable to pass an output signal to the input/output pad;
- a feedback circuit operable to cut off the output path during input mode, the feedback circuit including a feedback transistor coupled to the input transistor operable to disable the feedback path during output mode, and a pair of serially-coupled transistors coupled to a pass gate in the output path and the first transistor and operable to control the pass gate in response to the input signal;
- and
- a biasing circuit coupled to selected transistors in the output path, feedback circuit and output driver.
Dependencies are inferred from the claim text.