| 摘要 |
<p>PURPOSE:To use a clock at a frequency in wide range by selecting a signal inversion means with a program so as to change the driving capability of the signal inversion means. CONSTITUTION:One or more signal inversion means can be selected out of plural signal inversion means with the different driving capabilities with a program. When the value of a selection program S is 'H', for example, transistors 23 and 24 is turned off, transistors 21 and 22 is turned on and an inverter having the driving capability determined by the driving capabilities of transistors 11, 12, 21 and 22 is formed between an Xin and an Xout. When the value of a selection flag S is 'L', the transistors 21 and 22 is turned off, the transistors 23 and 24 is turned on and the inverter having the driving capabil ity determined by the capabilities of transistors 13, 14, 23, and 24 is formed between the Xin and Xout. Thus, since the driving capability of the signal inversion means can be changed, a stable clock can be obtained at both the low and the high frequencies.</p> |
