| 摘要 |
An oscillation circuits includes an oscillation unit 30 for generating an internal clock signal having an amplitude of vibration corresponding to an internal power supply voltage thereof, switches 28, 29, a NMOS 13 of a tolerant input circuit, a first-stage driver 15, and a coupling capacitance 27. The switches 28, 29 are turned off when the external clock signal is inputted to a clock terminals 1, 2, and are turned on when the oscillation unit 30 oscillates. The NMOS 13 changes the amplitude of the input clock signal by the on-resistance and the outputs the above input clock signal from the drain electrode. The first-stage driver 15 drives the output of the drain electrode of the NMOS 13 and outputs the output thereof as a clock signal. The coupling capacitance 27 changes the gate voltage of the NMOS 13 when the input clock signal rises so as to keep the above on-resistance constant.
|
