Sharp Kabushiki Kaisha Corporation

Tabuchi Electric Co., Ltd.

Other

Shinichi Masuda

Yutaka Takashige

Masaki Nakaishi

Shinobu Miyazaki

Hideaki Souma

Koji Ueda

Seiji Kambara

Fumiaki Yamagata

Sinobu Miyazaki

At least one of a start abnormality detector (), a temperature abnormality detector () and a voltage abnormality detector () has a latch inhibiting circuit for inhibiting retention of a detecting state when one of the abnormality detectors detects an abnormality, so that a current abnormality detector () can be inhibited from detecting an abnormal input current caused when the oscillation is halted by the abnormality detector. Accordingly, after the abnormality is removed, automatic resetting can be easily accomplished without causing the oscillation to halt as a result of the current abnormality detector detecting the presence of the abnormality. Also, since a power source abnormality detecting circuit () is designed in the form of an analog circuit, a low cost can be achieved and the monitoring level can be modified. In addition, the monitoring level associated only with the temperature abnormality occurring in an IGBT element () can be modified.

Inverter power source control for high frequency heater

An oscillation control signal generated by an inverter power source control circuit () includes a reference voltage setting signal for approximating the current waveform of the AC output form the AC power source () to a sinusoidal wave by making both sides of the waveform generate current according to the fluctuation of the PWM control signal, and a waveform shaping signal consisting of a peak adjustment signal of a sinusoidal waveform for approximating the waveform peak portion of the current waveform to a sinusoidal wave by subtraction. Accordingly, even if the PWM control signal fluctuates, it is possible to automatically improve the power factor of the power source circuit to a value higher than a predetermined value by approximating the current waveform of the AC output from the AC power source to the sinusoidal wave, thereby improving the efficiency of the power source.

An electromagnetic induction device having a flat configuration that requires a relatively small space for installation on a circuit substrate includes a flat bobbin ( T) having a length (D ) smaller than a radial size (D ) thereof has primary and secondary windings ( ) wound thereon. This bobbin ( T) has coaxially aligned throughholes ( ) defined therein into which core legs ( T and T) of generally T-shaped first and second core pieces ( T, T) are inserted from opposite directions, respectively. Respective core arms ( T, T) of the first and second core pieces ( T, T) extend parallel to each other.

Electromagnetic induction device

A high-frequency heating apparatus is designed to maximize the input current while securing a uniform margin relative to the cutoff current, thereby enabling maximized and efficient output of high-frequency waves. The high-frequency heating apparatus includes: a power supply unit; an input current detector; a power converting unit for converting the power from the power supply unit into high-frequency waves; an inverter controller for controlling a semiconductor device; a magnetron for radiating electromagnetic waves; and a circuit for implementing negative feedback control, in the inverter control circuit, of the output from the input current detector. The apparatus further includes a control circuit having a microcomputer for outputting signals to the inverter controller so as to control the input current such that the input current characteristic of the high-frequency heating apparatus will approximate the current cutoff characteristic of the overcurrent circuit breaker with respect to the elapsed time.

High-frequency heating apparatus for maximizing input current while securing a uniform margin relative to the cutoff current

A boosting transformer for a high-frequency heating apparatus includes an insulation member, and a primary winding and a secondary winding formed at the insulation member and mutually isolated by the insulation member, each winding having a width and a thickness as measured when the winding is stacked, the width being smaller than the thickness. As such, the boosting transformer can be reduced in height to readily ensure a distance for insulating locations having therebetween a large potential difference from each other in the transformer's internal structure in designing a structure in which the transformer is attached to a high-frequency heating apparatus. Thus the boosting transformer can be attached to the high-frequency heating apparatus at a location less restrictively and such designing can be facilitated.

Boosting transformer for high-frequency heating device

A multifunctional telephone capable of memorizing alphabetical characters and telephone numbers includes digit and function keys and a multi-row display unit. The lower row of the display is capable of displaying three groups of letters, A-I, J-R and S-Z above digits 0-9 printed on the face of the telephone. By pressing a corresponding digit key, a letter may be displayed on the upper row of the display. The upper row of the display is capable of showing a name while the lower row can display a telephone number. After the information has been entered into the telephone, it will be stored in memory. After pressing certain function keys, the telephone can search the memory for all information starting with a certain letter. This information will be sequentially displayed and may be automatically dialed after activation of certain other keys. Rather than displaying alphabet characters, 'KATAKANA' characters or other symbols may be shown. Also, other information may be input and stored by the multifunctional telephone.

Growing community of inventors

Tondabayashi, Japan

Shinichi Masuda