Patent ID: 7049876

Claim:
A level shift circuit for shifting a ground referenced positive logic level signal to an output signal referenced to a negative supply, the circuit comprising: an input for receiving the ground referenced positive logic level signal; an inverting circuit portion connected to receive the ground referenced positive logic level signal and to produce a complement logic signal therefrom; voltage divider circuitry to which both the ground referenced positive logic level signal and the complement signal are applied to produce a differential signal in the form of a first voltage divided signal corresponding to the ground referenced positive logic level signal and a second voltage divided signal corresponding to the complement logic signal, the voltage divider circuitry referenced to a negative voltage supply; and comparator circuitry to which the differential input signal is applied, the comparator circuitry producing the output signal which is referenced to the negative voltage supply, the output signal set to a higher voltage or a lower voltage according to a difference between the first voltage divided signal and the second voltage divided signal.