| 摘要 |
PROBLEM TO BE SOLVED: To synchronize a main equipment with a terminal equipment even when the switching power oscillating circuit of the terminal equipment is eliminated and to suppress interference to a control signal, etc., by permitting control signal carrier wave included in a power source on which a control signal from the main equipment is superimposed to be the operating signal of a switching power circuit. SOLUTION: When a prescribed voltage is applied to the terminal equipment TR from the main equipment by superimposing the control signal on carrier wave, a waveform V2 obtained by rectifying a transmission waveform MIX by a rectifying waveform circuit BD with connecting terminals S1 and S2 is adopted an output voltage V4 by way of a power source circuit PW. A switching transistor Q is turned on/off by the height of the voltage V4 as the result of comparison of the voltage V4 with a reference power source ST voltage Vref by a comparator CMP so as to generate the cut-off waveform V3 and the prescribed voltage V4 is outputted from the power source circuit PW so as to be applied to the respective parts of the terminal equipment TR as a power source Vcc with a driver circuit DR. In this way, control signal carrier wave on which the control signal of the main equipment is superimposed is adopted as the operation signal of the switching power circuit. |
