Yokogawa Electric Corporation

Yokogawa Hokushin Electric Corp.

Masuo Hanawaka

Masaki Shioya

Tomohiro Nishiyama

Masato Yamamoto

Kenta Mikuriya

Hideaki Matsumura

Hideo Hirukawa

Iwao Nakanishi

Koji Takada

Takumi Ooe

Yoshio Fukai

Akira Ohya

Shoji Uehara

Yoshinao Naito

Kenichi Yamakawa

A DC/DC converter having a control circuit to reduce losses at light load, wherein a first control device turns ON and OFF power to the primary winding of the transformer of the DC/DC converter according to the difference between the output voltage of the DC/DC converter and the desired output voltage, and a second control device turns ON a switching device of a clamping circuit connected to the primary winding for a desired length of time after the first control device turns OFF the power to the primary winding.

DC/DC converter having a control circuit to reduce losses at light loads

A pulse width control IC circuit that greatly reduces price, increases packaging density,and improves reliability for switching power supply units, wherein the IC circuit is on a single chip and includes a main converter control section that controls the ON and OFF actions of a main switch outside the IC, an output MOSFET, and an auxiliary converter control section that controls the ON and OFF actions of the output MOSFET.

Pulse width control IC circuit and switching power supply unit

A switching power source of a voltage resonant type having a circuit for detecting the lowest point of voltage applied to both ends of a switching element, a time signal generating circuit which is activated concurrently with the turning ON of the switching element to output a predetermined time signal, and a circuit for inhibiting the turning ON of the switching element based on the lowest point detection signal, while a time signal is outputted from the time signal generating circuit.

Switching power source of the voltage resonance type

A switching power supply for controlling an output voltage to a constant value with respect to fluctuations in input or in load, wherein are provided a DC power supply; two dividing capacitors connected in series to both ends of the DC power supply; two semiconductor switches connected in series to both ends of the DC power supply; a transformer having a primary winding, one end of which is connected to a connecting point of the two dividing capacitors; and a T type circuit comprising two inductors connected in series between the connecting point of the two semiconductor switches and the other end of the primary winding; and a capacitor connected between the connecting point of the two inductors and the other end of the primary winding. The control characteristics of the switching power supply are improved by reducing the dependency of the output voltage on fluctuations in the load.

Switching power supply

A test system for optical disks, comprising a spindle motor for bearing and rotating an optical disk at a constant speed; a measuring head, comprising focus servor and tracking servo mechanisms for causing the focal point of a laser beam irradiating the optical disk to follow the guide groove of the disk, for generating an output signal proportional to the intensity of the reflected beam coming from the optical disk; a feed mechanism for moving the measuring head in a radial direction of the optical disk; a control circuit for controlling the operations of the spindle motor, the focus servo and tracking servo mechanism of the measuring head, and the feed mechanism; a measurer for performing desired measurements in response to the output signal from the measuring head; and a computer for commanding the control circuit and the measurer and for processing the measured data of the measurer, whereby all the measurements are accomplished with the guide groove of the disk being under the focus and tracking servos.

Test system for optical disks

A programmable controller is provided with a controller body including a microprocessor having a ROM for storing user programs connected with a socket thereto. A programmer which is connected by a connector to a data bus or the controller body has a means to switch to a program mode to write a user program in a RAM by operating keys, and a test run mode to execute the user program written in RAM on the controller body, and a means to copy the user program written in RAM of the programmer to said ROM. The user program stored in ROM which is inserted in said socket is executed when the programmer is isolated from the controller body. The system program of the controller body includes a basic control function program for executing a single loop control, a cascade control function program for executing the cascade control and a selective control function program for the selective control, so that the control operation function is decided by selecting one of said control operation functions programs by a single instruction of the user programs.

Growing community of inventors

Tokyo, Japan

Masuo Hanawaka