| 摘要 |
PURPOSE:To effectively detect latchup phenomenon by connecting C-MOS group through an overcurrent detecting element, a switching element to a power source and inputting the output of a detecting element through a filter to a comparator and controlling the switching element with the output of the comparator. CONSTITUTION:A C-MOS group 4 of an input/output unit which feasibly occurs a latchup phenomenon is, for example, connected through an overcurrent detecting element 2 and a switching element 3 to a power source voltage VSS. The output side A of the element 2 is connected through a filter 11 to a C-MOS comparator 12, and the output of the comparator is connected to a flip-flop 13, thereby controlling the switching element 3. When the group 4 normally operates, the operating current flows in pulsating state. Accordingly, the flip-flop 13 does not invert. When it becomes latchup state, the output of the filter 11 decreases, thereby operating the comparator 12. Since the flip-flop 13 is thus inverted, the element 2 is interrupted. |
