Patent ID: 7282981

Claim:
A level shift circuit for changing the signal level in a first logic circuit fed from a first power supply to the signal level in a second logic circuit fed from a second power supply, comprising: a level shift core circuit which is controlled by a control circuit; wherein: the level shift core circuit, being fed from the second power supply, receives level shift input signals output from the first logic circuit and control signals output from the control circuit and outputs level shift output signals to be input to the second logic circuit; the control circuit comprises: a first NOR circuit fed from the second power supply, which receives an inverted signal of the level shift input signals and a non-inverted signal of the level shift output signals; and a second NOR circuit fed from the second power supply, which receives a non-inverted signal of the level shift input signals and an inverted signal of the level shift output signals; where the control circuit outputs the output signals of the first and second NOR circuits as control signals to the level shift core circuit; and the level shift core circuit comprises: a PMOS cross-coupled latch including a first plurality of PMOSs, a differential PMOS switch including a second plurality of PMOSs, and a differential NMOS switch including a plurality of NMOSs: wherein each PMOS of the second plurality of PMOSs has a source connected to a drain of a PMOS of the first plurality of PMOSs, a drain connected to the level shift output, and a gate connected to one of the control signals from the control circuit; wherein each PMOS of the first plurality of PMOSs has a source connected to the second power supply, a gate connected to the level shift output through the drain of another PMOS of the second plurality of PMOSs, where the other PMOS of the second plurality PMOSs does not share a drain to source connection with the PMOS of the first plurality of PMOSs; and wherein each NMOS of the differential NMOS switch has a source connected to the ground voltage GND, a drain connected to the level shift output, and a gate connected to the level shift input.