Abstract: Variation in inductance is reduced with a secondary-side coil substrate on which a plurality of wiring layers are superimposedly disposed, and a plurality of coils provided in the secondary-side coil substrate. On the wiring layer, coil patterns corresponding to parts of one circumferences of the coils are formed. On the wiring layer, coil patterns corresponding to remaining parts of the one circumferences of the coils are formed. The coil patterns, and the coil patterns that are provided on the different wiring layers are connected to each other via conduction points in a superimposition direction of the wiring layers, and the one circumferences of the respective coils are formed.

Abstract: A planar transformer includes: a primary side planar air core coil; a secondary side planar air core coil; a primary side planar core; and a secondary side planar core. The secondary side planar air core coil is arranged so as to be spaced from the primary side planar air core coil in the winding center axis direction of the primary side planar air core coil, the secondary side planar air core coil having a non-facing portion configured not to face the primary side planar air core coil in the winding center axis direction. The primary side planar core and the secondary side planar core are stacked on outer sides of the primary side planar air core coil and the secondary side planar air core coil in the directions of the winding center axes, respectively.

Abstract: A planar transformer includes: a primary side planar air core coil; a secondary side planar air core coil; a primary side planar core; and a secondary side planar core. The secondary side planar air core coil is arranged so as to be spaced from the primary side planar air core coil in the winding center axis direction of the primary side planar air core coil, the secondary side planar air core coil having a non-facing portion configured not to face the primary side planar air core coil in the winding center axis direction. The primary side planar core and the secondary side planar core are stacked on outer sides of the primary side planar air core coil and the secondary side planar air core coil in the directions of the winding center axes, respectively.

Abstract: A direct current (DC)-DC converter includes: a transformer; a half bridge circuit provided on a primary side of the transformer; a synchronous rectification circuit provided on a secondary side of the transformer; and a controller configured to switch a power semiconductor device for rectification of the synchronous rectification circuit at a duty ratio and a phase corresponding to an input voltage of the half bridge circuit and an output current of the synchronous rectification circuit.

Abstract: A direct current (DC)-DC converter includes: a transformer; a half bridge circuit provided on a primary side of the transformer; a synchronous rectification circuit provided on a secondary side of the transformer; and a controller configured to switch a power semiconductor device for rectification of the synchronous rectification circuit at a duty ratio and a phase corresponding to an input voltage of the half bridge circuit and an output current of the synchronous rectification circuit.

Abstract: A battery state diagnosing device applies load to a battery from a load applying section, measures input and output characteristics of the battery, and diagnoses a state of the battery by plugging a result of measurement into a mathematical expression obtained by a system identification method. In the battery state diagnosing device, a current load is used as the load applying section. With this arrangement, the battery state diagnosing device is capable of suitably determining, for example, life and state-of-charge of the battery.

Abstract: A battery state diagnosing device applies load to a battery from a load applying section, measures input and output characteristics of the battery, and diagnoses a state of the battery by plugging a result of measurement into a mathematical expression obtained by a system identification method. In the battery state diagnosing device, a current load is used as the load applying section. With this arrangement, the battery state diagnosing device is capable of suitably determining, for example, life and state-of-charge of the battery.