| 摘要 |
Between a first negative voltage level shifter which is made up of transistors having a normal breakdown voltage and which shifts an input signal of a level Vcc or Vss to a level Vcc or Vnmin, and a second negative voltage level shifter which is made up of transistors having a normal breakdown voltage and which shifts an input signal of a level Vnmin or Vss to a level Vss or Vneg, is provided an inverter 8 for converting the level Vcc or Vnmin derived from the first negative voltage level shifter to the level Vnmin or Vss and then feeds the resulting voltage level to the second negative voltage level shifter. Vnmin, which is an intermediate level between Vss and Vneg, is set so that the maximum voltage difference of voltages applied to the transistors of the first negative voltage level shifter becomes equal to or smaller than the breakdown voltage. Thus, an output of Vneg (Vss-breakdown voltage of transistors of second negative voltage level shifter) lower in level than the conventional Vneg (Vcc-Vss-breakdown voltage) is obtained. As a result, the absolute value of the outputted negative voltage can be increased without increasing the breakdown voltage of the transistors.
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