| 摘要 |
PURPOSE:To hold a boosted level for a long period by providing a charge pump circuit to an output circuit which generates an output signal boosted above a source voltage. CONSTITUTION:MOS Transistors (TR) 5, 6, 7, and 8 and a capacitor 9 for a charge pump constitute the charge pump circuit 12. The output signal PHIB is boosted above the source voltage VCC at time t4. For example, the level ''H'' of the output signal PHIB decreases slightly owing to a leak current at time t6 after a long time is elapsed. Then when a clock signal PHIC from an oscillator 4 rises at time t7 from the level ''L'' to the level ''H'', the level at a node 11 is boosted above VCC+VTH by the capacity coupling of the capacitor 9 for the charge pump and the MOSTR8 turns on to supply a charge from the capacitor 9 to the output signal PHIB. Therefore, the level ''H'' of the output signal PHIB recovers at the time t7. |
