Patent ID: 7825638

Claim:
A device for charge balancing between individual cells having first and second terminals in a double-layer capacitor, especially in a multi-voltage motor vehicle electrical system, the device comprising: capacitors each being assigned to a respective one of the individual cells of the double-layer capacitor, said capacitors each having first and second terminals; first switches each for connecting said first terminal of one of said capacitors to the first terminal of the respective assigned cell; second switches each for connecting said first terminal of one of said capacitors to the second terminal of the respective assigned cell; and said second terminals of all of said capacitors being interconnected; wherein said first and second switches are MOS-FET switching transistors having source and drain terminals in a charge balancing circuit for single operation; said first terminals of said capacitors are each connected to said source terminal of a respective one of said first switching transistors and to said drain terminal of a respective one of said second switching transistors; a node is connected at said interconnected said second terminals of said capacitors; said drain terminals of said first switching transistors are each connected to said first terminal of the respective assigned cell; said source terminals of said second switching transistors are each connected to said second terminal of the respective assigned cell; and series circuits of two resistors are each connected in parallel to a respective one of the cells and each have a connection point connected to said first terminal of said respective assigned capacitor.