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:
Aug. 07, 1990
Filed:
Jan. 13, 1989
Sampat S Shekhawat, Rockford, IL (US);
P John Dhyanchand, Rockford, IL (US);
Sundstrand Corporation, Rockford, IL (US);
Abstract
Prior base drive circuits for Darlington-connected transistors have accomplished a significant increase in the rate at which such transistors can be turned off and on. However, such circuits have utilized relatively numerous circuit elements or components to accomplish this result. In order to overcome this problem, a drive circuit 26 for rapidly switching driver and driven transistors Q3, Q4 connected in a Darlington configuration includes a first controllable switch Q1 coupled to a control electrode of the driver transistor Q3, an inductor L1 coupled to the first controllable switch Q1 and the control electrode of the driver transistor Q3 and a second controllable switch Q2 coupled to the control electrode of at least one of the transistors. A driving stage 32 is coupled to the controllable switches and closes same at the beginning of a turn on sequence to establish current flow through the inductor. The driving stage subsequently opens the second controllable switch while maintaining the first switch closed so that the current flow through the inductor is provided to the driver transistor to turn on same. The drive circuit utilizes fewer circuit components than prior drive circuits.