High-speed, low current level shifter circuits for integrated circuits having multiple power supplies

摘要

Level shifter circuits that provide fast operation when changing state while generating little crowbar current. Various embodiments are presented that include some of the following features added to conventional level shifters: additional pull-down transistors coupled to each output node and gated by the associated input signal; additional pull-up transistors coupled to each output node or cross-coupled internal node and gated by the associated input signal; additional pull-up transistors coupled to the cross-coupled internal nodes and gated by the opposing output node; and additional pull-down transistors on the output nodes gated by a low voltage power high. Some of these additional transistors allow the input signal to operate more quickly on the output nodes, causing more rapid transitions on the output signals and reducing crowbar current. The pull-downs gated by the low voltage power high ensure that little or no crowbar current occurs during the power-up sequence.