Nippon Steel Corporation

Hosei Hirano

Kenji Umetsu

Keiji Iwata

Shingo Katayama

Kenichi Tanigawa

Takatsugu Ueyama

Tetsuro Tanaka

Sueyuki Yahagi

Nobuyoshi Tanaka

A switching regulator including: a switching element connected to an input DC signal and operating for turning-on and -off the input DC signal to produce an AC signal such as a rectangular wave signal; a rectifier for rectifying the AC signal thereby generating an output voltage; a circuit for producing a frequency-variable triangular wave signal having a constant amplitude; a comparator for comparing the triangular wave signal with the output voltage of the rectifier thereby obtaining a pulse-width modulated signal used for controlling the operation of the switching element; a modulation signal generator for generating a modulation signal having an amplitude variable in asynchronism with the frequency of the triangular wave signal; a sampling and holding circuit for sampling the modulation signal at a timing in synchronism with the frequency of the triangular wave signal or preferably at the timing of a maximum or minimum value of the triangular wave signal and holding the sampled modulation signal; and a circuit for modulating the frequency of the triangular wave signal preferably within a range of about 0.8 to 1.2 times of a predetermined center frequency based on the voltage value of the modulation signal as sampled and held.

Switching regulator

Analysis of an electromagnetic field in a region including an electric conductor having an arbitrary shape is efficiently and accurately performed with a computer. A value of electric potential at a predetermined portion of the electric conductor or a value of the normal component of an electric current density vector to the cross section of a predetermined portion of the electric conductor is used as an initial condition. The distribution of exciting current density vectors in the electric conductor is obtained form the initial condition so as to meet the condition of continuity of electric current. The electromagnetic field of the region is analyzed by using the obtained distribution of exciting current density vectors.

Method for analyzing electromagnetic field

A thin DC-DC converter arrangement which includes an inductor including a thin ring-shaped coil having a hole in its center and a thin ferrite core for providing a closed magnetic path passing through the central hole of the coil and interlinking the ring-shaped coil, a thin circuit board formed on its one surface with an electric circuit of the DC-DC converter, and a radiator having at least one flat part, wherein the inductor, the circuit board and the radiator are integrally assembled.

Thin DC-DC converter arrangement

Growing community of inventors

Kawasaki, Japan

Hosei Hirano