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:
Dec. 08, 2015
Filed:
Feb. 05, 2015
Anand Kumar Sinha, Noida, IN;
Ashish Ojha, Lucknow, IN;
Ateet Omer, Kanpur, IN;
FREESCALE SEMICONDUCTOR, INC., Austin, TX (US);
Abstract
An oscillator includes an amplifier and a piezoelectric crystal coupled across a portion of the amplifier. A low pass filter (LPF) passes the common-mode voltage component of the crystal output signal. An auxiliary bias circuit uses a shared LPF component to charge a crystal load capacitor during start-up of the oscillator, and to provide a DC bias operating point to the oscillator driver transistor. A buffer amplifier receives the common-mode voltage component on the non-inverting input. The buffer amplifier output is coupled to both the inverting input and the drain terminal of the oscillator driver transistor such that the gate and drain DC bias voltages of the oscillator driver transistor are substantially the same. An automatic loop control circuit receives the crystal output signal and the common-mode voltage signal, and generates a bias control signal to bias the amplifier and the auxiliary bias circuit.