| 摘要 |
PROBLEM TO BE SOLVED: To provide a contactless electric power transmission device, which achieves oscillation stop or reduction of oscillation intensity of a power supply part while a load part is not mounted on, with a simple circuit structure, further small and at a low cost. SOLUTION: A feedback loop to control switching operation of a switching element FET1, is formed by magnetically connecting a primary coil Nm1 for power transmission, a secondary coil Nm2 for power transmission and a first coil Nf1 for control, respectively, when the load part 20 is mounted on the power supply part 10; and the switching element FET1 becomes in a stably turned-on state, since a gate voltage Vg becomes VB+VNf1 , and the coil voltage VNf1 of the first coil Nf1 for control becomes the threshold of the switching element FET1 or higher. The feedback loop is not formed in a state while the load part 20 is not mounted on the power supply part 10, a self-excited oscillation in the power supply part 10 becomes of an intermittent one. |
