Patent ID: 6278444
Filing Date: 2001-08-21
Classification: G06F

Abstract:
An interface converter to couple a five-wire touch-screen to a four-wire interface, the interface converter comprising:a current injection device, wherein said current injection device supplies a constant current to an outer screen member of said five-wire touch-screen when said five-wire touch-screen is coupled to said interface converter and said five-wire touch-screen is compressed;a logic element coupled to said four-wire interface, said logic element sensing a mode of operation of said four-wire interface;a switching element coupled to said logic element, wherein said switching element routes a reference voltage from said four-wire interface to said current injection device when said four-wire interface is coupled to said interface converter, wherein said constant current is based on said reference voltage;a plurality of current converters coupled to a set of four inner screen member electrodes of said five-wire touch-screen when said five-wire touch-screen is coupled to said interface converter, wherein said plurality of current converters convert a plurality of position proportional currents to a plurality of position proportional voltages; anda logic amplifier coupled to said plurality of current converters, wherein said logic amplifier outputs a first voltage and a second voltage, wherein said first voltage is proportional to a x-coordinate of a five-wire touch-screen compression point and said second voltage is proportional to a y-coordinate of said five-wire touch-screen compression point, wherein said first and second voltages are routed to said four-wire interface when said four-wire interface is coupled to said interface converter.