Patent ID: 7973560

Claim:
A level shifter that converts an input signal having an amplitude between a ground and a first power supply voltage into an output signal having an amplitude between the ground and a second power supply voltage, said level shifter comprising: an input unit, driven by said first power supply voltage, that raises a first pulse signal at a rise of said input signal and raises a second pulse signal having the same polarity as said first pulse signal at a fall of said input signal; a level shift unit that includes a first level shift circuit that converts a signal level of said first pulse signal into an amplitude level of said second power supply voltage, and a second level shift circuit that converts a signal level of said second pulse signal into an amplitude level of said second power supply voltage; an output unit, driven corresponding to said first and second pulse signals whose levels have been converted, that generates said output signal and is operated by said second power supply voltage; and a hold unit that holds a level of said generated output signal and is operated by said second power supply voltage, wherein said input unit causes said first pulse signal to fall in response to a rise of said output signal and second pulse signal to fall in response to a fall of said output signal, and wherein each of said first and second level shift circuits comprises: a transistor of a first conductivity type including a gate that receives said first and second pulse signals respectively, a source that connects to the ground, and a drain that outputs a pulse signal whose level has been shifted; and a first transistor of a second conductivity type including a gate that connects to the gate of said transistor of the first conductivity type, a drain that connects to the drain of said transistor of the first conductivity type, and a source that connects to a second power supply via a connected transistor group, wherein said connected transistor group comprises one or more transistors of the second conductivity type.