| 摘要 |
PURPOSE: To miniaturize and microminiaturize an electronic device by detecting a current in a primary winding by detector means, and exciting inductance of the primary winding by a bidirectional current source, in response to the detection means, so as to protect the inductor from a surge current and to make the inductor operative when a zero DC current flows. CONSTITUTION: Two half parts 14 and 15 of the primary winding of a detection transformer 16 and a primary winding 18 of an inductance transformer 20 are connected serially between inductor terminals 10 and 12. A secondary winding 19 of the inductance transformer 20 is connected to the output of a bidirectional current source 30. The current source 30 is controlled by a controller 40, including the detection transformer 16. To control the current of the current source 30, in response to the current in the primary winding 18, the controller 40 includes an operational amplifier 41 connected between a secondary winding 17 of the detection transformer 16 and an input resistor 38. Accordingly, the bidirectional current source 30 controls the current to the secondary winding 19 based on the output from the operational amplifier 41, for exciting the inductance of the primary winding 18. |
