US Patent 7688625 Circuit arrangement and method for operating a circuit arrangement

A circuit arrangement includes a nonvolatile memory cell having a continuously variable characteristic that can be read out. A programming unit is coupled to the memory cell and designed to apply an analog signal to the memory cell in order to vary the characteristic, if the characteristic lies within a predetermined range of values, in such a way that the characteristic lies outside the predetermined range of values. A supply voltage unit is provided for providing a supply voltage. A changeover unit is coupled to the supply voltage unit and to the programming unit and designed to trigger the application of the analog signal to the memory cell if the supply voltage is interrupted.