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Title:
LATCH STRUCTURE, FREQUENCY DIVIDER, AND METHODS FOR OPERATING SAME
Document Type and Number:
WIPO Patent Application WO/2010/033855
Kind Code:
A3
Abstract:
A latch includes three circuits. The first circuit drives a first output (QB) to a first level when a first input (D) and a first clock phase (CK) are both low, to a second level when D and CK are both high, and provides high impedance (HI-Z) when different logic levels are applied to D and CK. The second circuit drives a second output (Q) to the first level when a third input (DB) and a complimentary clock phase (CKB) are both low, to the second level when DB and CKB are both high, and provides HI-Z when different logic levels are applied to DB and CKB. The third circuit maintains voltages of Q and QB when the first and second circuits provide HI-Z at Q and QB. Odd-number dividers constructed with such latches produce 50% duty cycle operation without restricting output pulse widths to integer multiples of input periods.

Inventors:
ZHANG KUN (US)
BARNETT KENNETH (US)
Application Number:
US2009057555W
Publication Date:
September 30, 2010
Filing Date:
September 18, 2009
Export Citation:
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Assignee:
QUALCOMM INCORPORATED
ZHANG, KUN
BARNETT, KENNETH
International Classes:
H03K3/356; H03K5/156; H03K23/54
Domestic Patent References:
WO2001029965A12001-04-26
Foreign References:
US20060168487A12006-07-27
EP0926833A11999-06-30
US20060033523A12006-02-16
US20050253630A12005-11-17
US6389095B12002-05-14
EP1241788A12002-09-18
US20070286328A12007-12-13
EP1487108A12004-12-15
DE4340966C11995-01-19
Other References:
LEE S-H ET AL: "A Divide-by-16.5 Circuit for 10-Gb Ethernet Transceiver in 0.13-$mu$m CMOS", IEEE JOURNAL OF SOLID-STATE CIRCUITS, IEEE SERVICE CENTER, PISCATAWAY, NJ, US, vol. 40, no. 5, 1 May 2005 (2005-05-01), pages 1175 - 1179, XP011131315, ISSN: 0018-9200
MAGOON R ET AL: "RF local oscillator path for GSM direct conversion transceiver with true 50% duty cycle divide by three and active third harmonic cancellation", 2002 IEEE RADIO FREQUENCY INTEGRATED CIRCUITS (RFIC) SYMPOSIUM. DIGEST OF PAPERS. SEATTLE, WA, JUNE 2 - 4, 2002; [IEEE RADIO FREQUENCY INTEGRATED CIRCUITS SYMPOSIUM], NEW YORK, NY : IEEE, US LNKD- DOI:10.1109/RFIC.2002.1011502, no. 501, 2 June 2002 (2002-06-02), pages 23 - 26, XP002277201, ISBN: 978-0-7803-7246-7
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