US Patent 7145378 Configurable switch with selectable level shifting

A configurable bus switch is described where the bus switches are grouped into combinations as determined by logic inputs. NMOS transistors are the bus switches of choice, and programmable logic inputs select and enable groupings of these switches. Switch enable signals drive the NMOS transistor gates and turn on or off the groups according to the programmable logic inputs. Level shifting and undervoltage protection circuitry is described in preferred embodiments.