| US 7,484,149 B2 | ||
| Negative edge flip-flops for muxscan and edge clock compatible LSSD | ||
| David E. Lackey, Jericho, Vt. (US) | ||
| Assigned to International Business Machines Corporation, Armonk, N.Y. (US) | ||
| Filed on Mar. 14, 2006, as Appl. No. 11/276,768. | ||
| Prior Publication US 2007/0220382 A1, Sep. 20, 2007 | ||
| Int. Cl. G01R 31/28 (2006.01) | ||
| U.S. Cl. 714—726 | 1 Claim |

| 1. A flip-flop, comprising:
a master latch having a data input and a clock pin, said master latch configured to capture data presented at said data input
of said master latch and to transfer data stored in said master latch to said slave latch in response to a negative edge of
a clock signal presented to said clock pin of said master latch;
a slave latch having a data output, a first clock pin and a second clock pin, said slave latch connected to said master latch,
said slave latch configured to launch data stored in said slave latch to said output of said slave latch in response to a
negative edge of a clock signal presented to said first clock pin of said slave latch, said slave latch configured to load
data stored in said master latch in response to a clock signal presented to said second clock pin of said slave latch, said
second clock pin of said slave latch connected to a third clock signal;
a multiplexer having first and second data inputs, a select input and an output, said output of said multiplexer connected
to said data input of said master latch;
a first AND gate having a first input connected to a second clock signal, an inverted second input and an output, said output
of said first AND gate connected to said first clock pin of said master latch;
a second AND gate having a first input, an inverted second input and an output, said output of said second AND gate connected
to said second input of said first AND gate and to said first clock pin of said slave latch, said first input of said second
AND gate connected to a fourth clock signal, said second input of said second AND gate connected to a first clock signal;
and
wherein said first, second, third and fourth clock signals are different clock signals.
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