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. 17, 1999
Filed:
Oct. 31, 1996
Richard C Myers, McMinnville, OR (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A circuit for driving a power transistor in pulse mode, particularly adapted for use in a defibrillator. The gate of the power transistor is connected to the drain of a depletion mode transistor so no charge can build up at the gate of the power transistor when the depletion mode transistor is in its normal, conducting state. An electrical path is provided which allows current to flow, in response to a control signal, so that negative charge builds up at the gate of the depletion mode transistor, causing it to switch off (non-conducting), at which point the same current flow begins to charge the gate of the power transistor, switching it on. When the current flow is reversed, the gate of the depletion mode transistor is discharged and it switches back on, causing the gate of the power transistor to also discharge and turn the power transistor off. The various components are selected such that leakage current is less than 1 .mu.a with the resulting power pulse lasting about 25 ms. The power transistor is preferably a MOSFET or IGBT, and the depletion mode transistor is preferably a MOSFET or a JFET.