IC-chip operation inhibitor
US5619155A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 2, 1995 |
| Grant date | Apr 8, 1997 |
| Priority date | — |
| Expiry date | Jun 2, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K19/003
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An IC chip operation inhibitor to prevent operation of an IC chip in a system having a clock rate that exceeds a predetermined reference clock rate for the chip. The inhibitor has a frequency detecting device that generates at least one reference frequency. It compares the system clock with the reference frequency and prevents the chip from operating if the system clock frequency is greater than the reference frequency. The invention includes an external actuating device coupled to the frequency detecting device for generating a compare enable signal to actuate the comparing function of the frequency detecting device, and for generating a frequency select signal for selecting one of the built-in reference frequencies to be compared with the system oscillating frequency. The external actuating device may be turned off in order not to actuate the comparing function of the frequency detecting device when it is sure that the system oscillating frequency will not be higher than the reference frequency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.