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. 25, 2007
Filed:
Aug. 18, 2006
Han-wen Hsu, Hsin-Chu, TW;
Chih-hsiung Chu, Taipei Hsien, TW;
Pao-ping MA, Hsin-Chu, TW;
MediaTek, Inc., Hsin-Chu Hsien, TW;
Abstract
An apparatus and method for automatic power control is disclosed. An optical recording apparatus utilizes a low-speed, peak-hold circuit to obtain and output a maximum of a front photodiode output signal during a predetermined window or plurality of windows of a total duration long enough to allow maximum peak-hold signal to stabilize. After stabilization, the maximum peak-hold signal is sampled and held in a sample and hold circuit. A reset then clears the signal and reinitializes the peak-hold circuit. In accordance with the difference between a reference voltage and the held peak-hold signal, a feedback controller unit outputs the required current level into a driving unit for producing desired recording pulses into a laser diode for recording information pits into an optical disc. A calibration gain may be used when, due to insufficient FPD response speed, the held signal is different than the real optical power output.