| 摘要 |
PROBLEM TO BE SOLVED: To prevent a positive high supply potential that a plus boosting charge pump circuit outputs from abnormally dropping when an inverter in an output stage of a drive circuit switches. SOLUTION: The drive circuit includes a Schmitt inverter 20 with switchable thresholds, an output inverter 30 with the output of the Schmitt inverter 20 applied thereto, and a feedback inverter 40 which switches the thresholds of the Schmitt inverter 30 according to the output voltage Vout of the output inverter 30. In this circuit, the Schmitt inverter 20 is switched from a high threshold Vth to a low threshold VtL in a process of a change in input voltage to the Schmitt inverter 20 from a high level to a low level. Consequently, variation in output voltage of the Schmitt inverter 20 to the high level is fast in the beginning and becomes slow from a midway. COPYRIGHT: (C)2008,JPO&INPIT
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