| 摘要 |
PURPOSE:To increase the rising speed of an output signal and to improve the rising characteristic of the output signal without increasing the capacity of a driver in the post stage by switching a power supply voltage to be applied to an output circuit to a high speed at the rise of an input signal. CONSTITUTION:If a control signal I is supplied when a P-channel MOS transistor (TR) 1 is ON, a P-channel MOS TR 3 is turned on and a voltage from a VH power supply is applied to the drain terminal of the TR 1. Simultaneously, the inverse of a control signal I is supplied and a P-channel MOS TR 2 is turned off. In such a case, the pulse width of the signal I is set up to a time corresponding to the rising time of an output signal OUT, and after the rise of the signal OUT, the TR 3 is turned off and a TR 2 is turned on to supply a voltage from a normal VDD power supply. Since a voltage from a VH power supply which is higher than the voltage of the normal VDD power supply is supplied to the source terminal at the ON of the TR 1, practical ON current can be increased and the rising characteristics of the signal OUT can be improved. |
