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. 25, 1995
Filed:
Feb. 28, 1994
Applicant:
Inventors:
Tomy Sebastian, Saginaw, MI (US);
Frank F Athari, Baltimore, MD (US);
Assignee:
Black & Decker Inc., Newark, DE (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H02P / ;
U.S. Cl.
CPC ...
318434 ; 388903 ; 388930 ; 361 31 ;
Abstract
The pulse width modulated DC motor speed control circuit indirectly senses motor current using sense MOSFETs and a peak detector circuit with storage capacitor for deriving an average motor current signal. The average motor current signal is used both in the feedback loop of the pulse width modulated speed control circuit and also in the motor shutoff or clutch circuit. The clutch circuit shuts off power to the motor when a user-settable torque is reached. The motor speed control circuit is therefore adapted for use in hand-held DC power tools such as screwdrivers and nutdrivers which stop rotation at a predefined torque.