| 摘要 |
PROBLEM TO BE SOLVED: To obtain a level shift circuit in which high speed level shift operation can be ensured even for an input signal having the power supply voltage of a low voltage system power supply which is set still lower. SOLUTION: N type transistors N1 and N2 for complementary signal input are constituted of low breakdown voltage elements so that they can perform level shift operation even when the power supply voltage of a low voltage system power supply VDD becomes still lower. Protective circuits B3 and B4 of the N type transistors N1 and N2 for complementary signal input are formed of N type transistors N3 and N4. A control circuit B5 controls the gate voltage of the N type transistors N3 and N4 in the protective circuits B3 and B4 to have the voltage of a high voltage system power supply VDD3 when the transistors N1 and N2 for signal input are turned on and have the voltage of a low voltage system power supply VDD when they are turned off. During level shift operation, the N type transistors N3 and N4 in the protective circuits B3 and B4 are turned on completely to accelerate level shift operation without limiting current flow. COPYRIGHT: (C)2007,JPO&INPIT
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