| 摘要 |
<p>PROBLEM TO BE SOLVED: To easily, accurately detect a load current with a high sensitivity by a simple constitution without adding a special component separately. SOLUTION: In the transformer T, an input of a power source is supplied to its primary winding Ta, and an output from its secondary winding Tb is supplied to a load. Further, a detecting winding Tc having a predetermined turn ratio to the winding Tb is wound near the winding Ta. When a load current flows to the winding Tb for a load due to a power consumption of the load, a voltage drop occurs between terminals of the winding Tb due to an internal resistance of the winding Tb and a magnetic reluctance of the transformer T. Since no load current flows in the winding Tc, a voltage corresponding to a voltage difference between terminal voltages of the windings Tb and Tc is present between terminals of a voltage detector VD. This voltage corresponds to an amplitude of the load current, and the load current is detected based on the detected voltage of the detector VD.</p> |
