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. 03, 1990
Filed:
Mar. 01, 1989
Ziyad H Doany, Austin, TX (US);
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
Abstract
An amplifier which has special application as an induction coil driver. A multi-frequency signal is used to modulate the pulse width of a square wave, resulting in a pulse modulated signal. The pulse modulated signal is divided into two delay signals. The falling edge of each pulse is delayed in one of the delay signals, while the rising edge of each pulse is delayed in the other delay signal. This creates a 'dead band' between the two signals for each pulse. The signals are used to drive two metal oxide semiconducting field-effect transistors, which are connected to positive and negative power supplies. The switching of the MOSFETs occurs during the dead band which, when combined with a novel inductor-diode circuit, results in high-efficiency power transfer. The amplified modulated signal is then subjected to a low-pass filter which cancels out the square wave carrier and switching noise. The amplified analog signal may then be applied to a non-tuned induction coil.