| 摘要 |
PURPOSE:To prevent a comparator which generates the reset signal of the CPU from oscillating and to resetting a CPU without fail after its stop by setting the operating voltage of the comparator lower than the operating voltage of the CPU. CONSTITUTION:If a large current flows to cause a drop below the operating voltage VL of the CPU 1, the CPU 1 stops as shown in figure (b), but when the drop stays above the comparator voltage Vc of the comparator in this voltage drop state, the CPU 1 stops operating at time T5 as shown in figure (b). The comparator 2, however, does not operate and the output of an inverter 5 rises toward the source voltage as shown in figure (d) according to the stop of an output signal. Then, the output is inverted as shown in figure (e) at timing T6 where this voltage exceeds the comparator voltage Vp of the comparator 6 and a trigger signal shown in figure (f) is outputted to the comparator 2 at the side of a resetting circuit.
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