US 5,189,359 AGranted

Solid state safety jumper cables

OwnerJames W. Kronberginventor

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Abstract

Solid state jumper cables for connecting two batteries in parallel, having two bridge rectifiers for developing a reference voltage, a four-input decoder for determining which terminals are to be connected based on a comparison of the voltage at each of the four terminals to the reference voltage, and a pair of relays for effecting the correct connection depending on the determination of the decoder. No connection will be made unless only one terminal of each battery has a higher voltage than the reference voltage, indicating "positive" terminals, and one has a lower voltage than the reference voltage, indicating "negative" terminals, and that, therefore, the two high voltage terminals may be connected and the two lower voltage terminals may be connected. Current flows once the appropriate relay device is closed. The relay device is preferably a MOSFET (metal oxide semiconductor field effect transistor) combined with a series array of photodiodes that develop MOSFET gate-closing potential when the decoder output causes an LED to light.

Claims4

Dependent claims

A device for use in connecting in parallel a first battery having two terminals to a second battery having two terminals, said device comprising:

conductor means for enabling current to flow to and from each of said four terminals;
means for comparing each of the voltages of said four terminals to a reference voltage, said voltages sampled from said conductor means, to determine which of said four terminals have voltages higher and which of said terminals have voltages lower than said reference voltage, said comparing means generating a high signal for each of said four terminals having a higher voltage and generating a low signal for each terminals having a lower voltage, said high and low signals generated by said comparing means forming a set of signals;
means for connecting either terminal of said first battery to either terminal of said second battery, said connecting means responsive to said high and low signals from said comparing means, said connecting means connecting one terminal of said first battery for which said comparing means has generated said high signal to one terminal of said second battery for which said comparing means has generated said high signal and the remaining terminal of said first battery for which said comparing means has generated said low signal to the remaining terminal of said second battery for which said comparing means has generated said low signal from so that said first battery and said second battery are connected in parallel;
and
two bridge rectifiers for selecting said reference voltage from said voltages of said four terminals so that said reference voltage is higher than the lowest voltage of said four terminals and lower than the highest voltage of said four terminals.

2 more elements

Dependencies are inferred from the claim text.