| 摘要 |
<P>PROBLEM TO BE SOLVED: To reliably recover from dead lock or malfunction by using small scaled and simple circuit configurations operating without fail in a semiconductor integrated circuit device for reducing an electromagnetic radiation noise by diffusing the spectrum of a clock signal. <P>SOLUTION: The device includes: a delay circuit which outputs a polyphase clock signal on the basis of a reference clock signal; a selection circuit which generates a modulation clock signal by selecting one of the polyphase clock signals in accordance with a selection signal; a clock stop detection circuit which outputs a reset signal when the generation of the modulation clock signal stops; a timing signal generation circuit which is reset by the reset signal, and which periodically generates a timing signal by counting the number of pulses included in the modulation clock signal; and a control circuit which generates the selection signal in order to increase and decrease the frequency of the modulation clock signal in a predetermined modulation cycle in response to the timing signal. <P>COPYRIGHT: (C)2013,JPO&INPIT |
