1. A circuit for placing a selected charge on the floating gate of a tunneling device, comprising: an analog comparing device having a first input operably coupled to the output of a tunneling device, the analog comparing device also having a second input selectably coupled to a reference signal; a level shifting device selectably coupled to the input of the tunneling device, the voltage level shifting device also operably coupled to receive input from an analog comparing device output; wherein the input of the tunneling device is selectably coupled to a reference node; and wherein, a feedback loop selectably couples the analog comparing device output to the second analog comparing device input; whereby a selected charge provided by the reference signal is placed on the floating gate of the tunneling device.