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:
Nov. 09, 2004
Filed:
Jan. 29, 2002
Compal Electronics, Inc., Taipei, TW;
Abstract
An input protection circuit is provided for protecting internal circuitry of a handheld electric device. The internal circuitry has a positive input node and a ground node. The input protection circuit includes a power socket having a positive input node and a ground node, a bipolar junction transistor (BJT), a metal-oxide semiconductor (MOS) transistor for controlling the on and off states of the BJT, and an overvoltage protective circuit. An emitter of the BJT is electrically connected to the positive input node of the power socket, and a collector is electrically connected to the positive input node of the internal circuitry. When a reverse DC voltage or a DC voltage exceeding a threshold inputs from the power socket, the overvoltage protective circuit will turn off the MOS transistor, thereby turning off the BJT to prevent damages of the internal circuitry.