Patent ID: 7982525

Claim:
A level shifter circuit comprising: a pull-up transistor coupled to a first input, a variable high supply rail having a nominal high supply voltage, and a high-side output; a pull-down transistor coupled to a second input, a variable low supply rail having a nominal low supply voltage; a floating battery element coupled to the pull-down transistor and the pull-up transistor, wherein the floating battery element maintains a voltage substantially equal to the nominal high supply voltage minus 1) the nominal low supply voltage and 2) a target swing voltage, wherein the floating battery element comprises: a battery transistor having an input and terminals, said terminals coupled to the pull down transistor and the pull up transistor, a bias network coupled to the input of the battery transistor, a high-side clamping transistor coupled to the high supply rail, the high-side output, and a high-side clamping voltage; and a low-side clamping transistor coupled to the low supply rail, the pull down transistor, and a low-side clamping voltage.