Abstract: A power feeding device which wirelessly transmits power towards a power receiving device equipped with a power receiving coil device, comprising: a magnetic structure having two magnetic bodies; and a power feeding coil device which receives power from a power supply and generates an alternating magnetic field, the mutual main surfaces of the two magnetic bodies face each other, and the two magnetic bodies are disposed to be separated at a predetermined distance, the power feeding coil device is disposed at any position between the two magnetic bodies, the two magnetic bodies receive the alternating magnetic field during power transmission, and a power feeding region in which transmitting power towards the power receiving coil device is possible is formed between the two magnetic bodies.

Abstract: A switching power supply capable of executing output voltage stabilizing control with a high degree of reliability even when the DC output voltage is at DC 2V or lower. A DC--DC converter unit 1 converts a DC input voltage Vin to DC through switching and outputs a DC output voltage Vo for a load 10 through output lines 71 and 72. An auxiliary power unit 3, which is electrically linked to the DC--DC converter unit 1, outputs a DC voltage Va through an auxiliary source output line 30 having a potential that is negative relative to the potential at the lower-potential output line 72. An output voltage detection unit 2, connected between the higher-potential output line 71 and the auxiliary source output line 30, detects a DC voltage (Vo+Va) manifesting between them and provides the detection signal to a control unit 4 via a photocoupler 9. The control unit 4 implements output voltage stabilizing control on the DC--DC converter unit 1.

Abstract: A coil assembly having a drum core for winding a coil wire. The drum core has a drum portion and a pair of end flanges provided at the opposite ends of the drum portion. The wire is wound on the drum portion. The drum core is encircled by a cylindrical ring core. The drum core and the ring core are supported by a base plate which has a recess for receiving end portions of the drum core and the ring core for appropriately locating the drum core and the ring core during assembling. The ring core is formed with cutouts leaving projecting edges at the end adjacent to the base plate. The base plate is provided with terminals at the edge portions adjacent to the cutouts of the ring core. End portions of the coil wire are passed through the cutouts and connected with the terminals.