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. 04, 2009
Filed:
Nov. 28, 2005
Sheng LI, Shenzhen, CN;
Sheng Li, Shenzhen, CN;
Hong Fu Jin Precision Industry (ShenZhen) Co., Ltd., Shenzhen, Guangdong Province, CN;
Hon Hai Precision Industry Co., Ltd., Tu-Cheng, Taipei Hsien, TW;
Abstract
A protection circuit for avoiding the use of an improper alternating current source includes: a rectifier circuit; a voltage comparator circuit having a first input terminal, a second input terminal, and an output terminal; a sampler and filter circuit; an alarm circuit connected to the output terminal of the voltage comparator circuit; and a switch control circuit. The rectifier receives a voltage from an external AC power and outputs a single-direction pulsed voltage. The sampler and filter circuit includes an input terminal connected to an output terminal of the rectifier circuit, and an output terminal connected to the first input terminal of the voltage comparator circuit. The switch control circuit enabled or disenabled by means of a control signal received from the voltage comparator circuit. One of the input terminals of the voltage comparator circuit accepts a constant reference voltage.