Patent ID: 7119578

Claim:
An integrated circuit (IC) comprising: a plurality of circuit rows; at least one low voltage island in at least one of said plurality of circuit rows, circuit elements in each said at least one low voltage island being powered by a low voltage (V ddl ) supply; and at least one high voltage island in said at least one of said plurality of circuit rows, circuit elements in each said at least one high voltage island being powered by a high voltage (V ddh ) supply) V ddh being a higher voltage than V ddl ; and, at least one level converter comprising: a first buffer receiving an input signal from said at least one low voltage island, said first buffer being connected between a virtual supply and a supply return; a second buffer receiving an output of said first buffer and connected between V ddh and said supply return; and a supply select between V ddh and said virtual supply, said supply select receiving an output from said second buffer and selectively passing V ddh or a reduced supply voltage to said virtual supply responsive to said output from said second buffer.