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:
May. 21, 1996
Filed:
Nov. 19, 1993
Joseph J Kopera, Jr, Trenton, MI (US);
Thomas J Wand, Canton, MI (US);
Chrysler Corporation, Auburn Hills, MI (US);
Abstract
A power supply polarity reversal protection device includes a voltage controlled switching device, e.g. an N-channel MOSFET connected between the power supply output (e.g. a positive supply voltage) and the circuit to be powered by the supply, i.e. the load. A diode, preferably the parasitic diode inherent in the MOSFET between the drain and source, is arranged so that when the positive supply terminal is connected to the transistor, the diode is forward biased and will allow a diode current to flow. A sensing means generates a control terminal voltage in response to the diode current flow. This control terminal voltage is applied to the switching means control gate and is sufficient to cause full conduction through the switching means. If, instead, a negative supply voltage is connected to the transistor, the diode will be reverse biased and no current will flow. Since there is no diode current, the sensing means will not generate a control terminal voltage and the switching means will not turn on, thus protecting the load.