Abstract: A circuit module equipped with a primary coil of a step-down transformer formed by primary coils of a plurality of transformer elements connected in series with each other and a secondary coil formed by secondary coils of the transformer elements connected in series with each other, includes a printed substrate on which the transformer elements are mounted in a lengthwise direction, a connection terminal coupled to a first end of the primary coil of the step-down transformer and connection terminals coupled to the secondary coil of the step-down transformer, the connection terminals are positioned such that the transformer elements are interposed therebetween. As a result, provided are a transformer module that reduces the effect of a high-voltage portion on a low-voltage portion by securing a distance between the high-voltage portion and the low-voltage portion, and a power reception device and a power transmission device equipped with the transformer module.

Abstract: A power transmission system and power transmitter device that suppress degradation of communication quality in data communication even when the data communication and power transmission are performed concurrently. One end portion of a first communication unit of a power transmitter device is connected to a first communication coupling electrode, and one end portion of a second communication unit of a power receiver device is connected to a second communication coupling electrode that forms capacitive coupling with the first communication coupling electrode. The other end portion of the first communication unit is connected to a reference potential electrode of the power transmitter device, and the other end portion of the second communication unit is connected to a reference potential electrode of the power receiver device.