The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Jul. 23, 2013

Filed:

Sep. 28, 2010
Applicants:

Honkai Tam, Redwood City, CA (US);

BO Tang, Sunnyvale, CA (US);

Inventors:

Honkai Tam, Redwood City, CA (US);

Bo Tang, Sunnyvale, CA (US);

Assignee:

Apple Inc., Cupertino, CA (US);

Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
H03K 3/356 (2006.01); H03K 3/289 (2006.01);
U.S. Cl.
CPC ...
Abstract

A scannable latch circuit is disclosed. In one embodiment, the scannable latch circuit includes a master latch, a slave latch, and a gating circuit coupled between the master latch and the slave latch. The slave latch may be implemented to support scan-shifting for test operations. Scan data received by the master latch may be provided to the slave latch through the gating circuit. The gating circuit may enable data to be transferred from the master latch to the slave latch when a scan enable signal is asserted. When the scan enable signal is deasserted, the gating circuit may cause the slave latch to output a constant (i.e. unchanging) state, regardless of the state of data stored in the master latch. This may result in power savings by inhibiting the slave latch from making state changes when scan-shifting operations are not in progress.


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