| 摘要 |
PURPOSE:To separate electrically and automatically a defective electronic circuit block from a system, by providing the respective switches between the external terminals of each electronic circuit block and a power source voltage wiring, and between said terminals and a ground voltage supplying wiring. CONSTITUTION:A PMOSFET 3 and an NMOSFET 4 are arranged between a wiring to supply the power source voltage VCC of an electronic circuit A0 and the external terminals of A0, and between a wiring to supply the ground voltage VSS and the external terminals of A0. When a signal voltage (5V) is output by a selection circuit F0 according to a control signal Sb, each transistor turns to a conduction state, and the electronic circuit block A0 is selected. When the selection circuit P0 outputs a signal (0V), each transistor turns to a non-conduction state, and the electronic circuit A0 is not selected. Fuses 19 and 18 are arranged between a power source voltage wiring 17 and the external terminals of the electronic circuit block A0, and between the wiring 17 and a wiring to supply the ground potential. When the electronic circuit A0 turns to a defective, and a large current is generated, the fuses 19 and 18 flow. |
