High voltage switch using low voltage cmos transistors

Abstract

The invention relates to an electronic switch capable of rail-to-rail input voltage swing exceeding the voltage rating for a certain technology in which the switch element of the switch is implemented. For example the switch element could be a complementary coupled pair of nMOS and pMOS transistors in a CMOS technology. Two voltage dividers are used to provide a floating supply voltage to the switch element from the supply voltage. This floating supply voltage is always within the supply voltage independent from the input voltage thus allowing a rail-to-rail voltage at the input terminal of the switch while keeping the floating supply voltage within the critical breakdown voltage for the switch element. A switch according to the invention may be formed in standard CMOS technology and it can be implemented to function at switching frequencies up to at least 50 MHz. The switch elements according to the invention can be cascaded thus obtaining an even higher maximum differential input-output voltage than with one switch.

Dependencies are inferred from the claim text.