Sharp Kabushiki Kaisha Corporation

Hideyuki Imanaka

Toshiya Fujiyama

Ryohta Takahashi

Hirofumi Tsunano

Yasuo Kudara

Gen Ueuchi

A flyback-type switching power supply circuit provided with a transformer including a primary coil and a secondary coil, and a switching element connected to the primary coil, comprising: a multiplying circuit for multiplying a first value obtained by multiplying the on-duty ratio of a secondary current flowing to the secondary coil by a predetermined first constant, and a second value obtained by multiplying the peak value of a primary current flowing to the primary coil by a predetermined second constant; and a switching control circuit for controlling switching of the switching element so that the result of multiplication by the multiplying circuit and a third value obtained by multiplying a reference voltage by a predetermined third constant match; and the flyback-type switching power supply circuit is configured so that at least one of the first constant, the second constant, and the third constant is variable by an external signal.

Switching power supply circuit and LED illumination device

Providing a power control device of a simple structure which increases the reliability of a circuit as incorporated therein. A semiconductor component constituting a power control device comprises a semiconductor chip, atop of which a cathode and a gate are formed via an oxide film portion. The cathode comprises a pad portion, a fusion portion and a contact portion. The pad portion and the contact portion are interconnected by the fusion portion only. An anode is formed at the bottom of the semiconductor chip. With the flow of a fusing current through the fusion portion, the fusion portion is fused by heat generated therefrom whereby the current flow through the cathode and the anode is interrupted.

Growing community of inventors

Osaka, Japan

Hideyuki Imanaka