公开(公告)号：JPH0916281A

公开(公告)日：1997-01-17

申请号：JP15950395

申请日：1995-06-26

Applicant: UNITED MICROELECTRONICS CORP

Inventor： WAN SONNTEIN

IPC: G06F1/04 ,  H01L21/822 ,  H01L27/04 ,  H03K5/26 ,  H03K19/003

Abstract: PURPOSE: To provide an IC chip operation suppressing device capable of preventing the operation of an IC chip in a system having a clock rate exceed ing a prescribed reference clock rate for the chip. CONSTITUTION: The suppressing device has a frequency detector 40 for generating at least one reference frequency. The device compares a system clock 50 with the reference frequency, and when the system clock frequency is more than the reference frequency, prevents the operation of the chip. The device can include an external actuator 20 connected to the detector 40 and allowed to generate a comparison permission signal, actuate the comparing function of the detector 40 and generate a frequency selection signal for selecting one of plural built-in reference frequency values to be compared with system oscillation frequency. When the system oscillation frequency is surely less than the reference frequency, the actuator 20 can be turned off so as not to actuate the comparing function of the detector 40.