| 摘要 |
<p>PURPOSE:To prevent the malfunction of control by providing a voltage transformer to transform the voltage of an input signal and to supply it to a comparator corresponding to a current to flow, and a detection circuit to detect the voltage fluctuation of a second power source and to output a control signal to the said voltage transformer corresponding to this detection, and also providing a circuit to arbitrarily set the fluctuation detection level of the second power supply voltage to the said detection circuit. CONSTITUTION:A second voltage fluctuation detection level setting circuit 22 composed of a transistor Q1 and a power source V1 is provided in the electronic circuit. As the transistor Q1, a PNP bipolartransistor is used and the emitter is connected to a switch SW. Then, the collector is connected to the collector and base of a transistor Q2 in a current mirror circuit. Thus, by arbitrarily changing the voltage V1 of the said power source 23, a current IB to flow in a resistor RSW can be freely changed according to the value of a first power source 14 (+B) and a third power source. When depending on the +B voltage, the threshold voltage of a comparator 13 can be freely changed by controlling a voltage depending on an RIN, RSW, the +B voltage of the first power source and the voltage V1 of the third power source.</p> |
