Murata Manufacturing Co., Ltd.

Koji Kitamura

Koji Nishi

Takayoshi Nishiyama

Tadahiko Matsumoto

Hitoshi Tsuji

Seiichi Takahashi

Yoshihiro Matsumoto

A DC-DC converter includes a primary side circuit for allowing a switching device to perform on/off operations to output energy in a primary coil of a transformer to a secondary coil. A secondary side circuit rectifies and smooths a voltage outputted from the secondary coil so as to output a DC-DC voltage. A voltage-detecting circuit rectifies and smooths a voltage outputted from a voltage-detecting coil provided in the transformer so as to output the voltage as a detected voltage corresponding to a voltage to be outputted from the secondary side circuit. A control circuit applies to the switching device a pulse control signal used for controlling on/off operation of the switching device according to the voltage outputted from the voltage-detecting circuit. A primary side current-detecting circuit converts a working current in the primary side circuit, the working current corresponding to a current in the secondary side circuit, for performing detection thereof, and for superposing the thus detected voltage corresponding to the working current with the detected voltage outputted from the voltage-detecting circuit so as to compensate for an amount of variation of an output voltage of the secondary side circuit. The variation is attributed to a variation of the working current in the secondary side circuit. A voltage determined by the superposed voltage is applied to the control circuit.

DC-DC converter which compensates for load variations

When a multilayer substrate is formed by alternately laminating a plurality of substrates having coil patterns and preimpregs including an epoxy resin, and by pressing in the direction of lamination while heating, the epoxy resin is melted and may leak from between the substrates, and may form voids between the coil patterns so as to render the electrical insulation therebetween unsatisfactory. According to the present invention, a fence pattern or another structure is formed around each coil pattern, which substantially prevents leakage of the melted epoxy resin from between the substrates, and therefore, the spaces between the coil patterns remain securely filled with the epoxy resin.

Multilayer substrate

Growing community of inventors

Nagaokakyo, Japan

Koji Kitamura