Scan flip-flop and associated method
AssigneesGlobal Unichip Corporation, Taiwan Semiconductor Manufacturing Company, Ltd.
InventorsSho-Mo Chen, Chien-Cheng Wu
Life of this patent
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Abstract
Scan flip-flop and associated method are provided. The scan flip-flop includes a data input terminal, a scan input terminal, a flip-flop circuit, a first transistor and a plurality of second transistors. A gate of the first transistor is coupled to the scan input terminal, gates of the second transistors are commonly coupled to an enabling signal, drains and sources of the first transistor and the second transistors are serially coupled to the flip-flop circuit, so as to increase a delay between the scan input terminal and the flip-flop circuit.
Claims3
A scan flip-flop, comprising:
- a data input terminal coupled to a data signal;
- a scan input terminal coupled to a scan input signal;
- an internal circuit comprising a first internal input terminal, capable of latching an internal signal received via the first internal input terminal in response to a clock;
- a first transistor comprising a first gate, a first source and a first drain;
- and
- a plurality of second transistors, each of the plurality of second transistors comprising a second gate, a second source and a second drain;
- and
- a third transistor comprising a third gate, a third source and a third drain, the third source and the third drain being coupled between the first internal input terminal and the data input terminal, and the third gate being coupled to a second enabling signal;
- wherein the second sources and the second drains of the plurality of second transistors, and the first source and the first drain, are serially coupled between a first voltage and the first internal input terminal, the first gate is coupled to the scan input terminal, and the second gates of the plurality of second transistors are commonly coupled to a first enabling signal, and
- wherein the second enabling signal and the first enabling signal are of opposite phases.
Dependencies are inferred from the claim text.