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.
Patent No.:
Date of Patent:
Apr. 12, 2011
Filed:
Aug. 14, 2009
Chris C. Dao, Pflugerville, TX (US);
Stefano Pietri, Austin, TX (US);
Wenzhong Zhang, Tianjin, CN;
Freescale Semiconductor, Inc., Austin, TX (US);
Abstract
An oscillator circuit has a crystal oscillator amplifier having only two clock input terminals, one being an input terminal and the other being an output terminal. The input terminal allows a user of the integrated circuit to choose between connecting a first clock signal generated from a crystal or a second clock signal generated by a non-crystal source to the input terminal. Control circuitry has a capacitor coupled in parallel with a transistor. Both are coupled in series with a resistive device at an output of the control circuitry to provide a control signal. Clock generation circuitry coupled to the crystal oscillator amplifier provides an oscillating output signal in response to an enable signal. In one form a comparator circuit provides the oscillating output signal. The control signal is used to ensure that inputs to the comparator circuit repeatedly cross each other over time.