Shindengen Electric Manufacturing Company Limited

Shigeru Hisada

Daisuke Arai

Mizue Kitada

Takeshi Asada

Wataru Miyazawa

Hideyuki Ono

Shinya Iijima

Hitoshi Koiwai

Provided is a control circuit which can discharge a charge stored in an X capacitor with certainty even when an alternating current input voltage largely fluctuates. The control circuit for controlling a discharge of an X capacitor Cconnected between power source lines ACand AChaving different polarities of an alternating current of an AC-DC convertor which receives inputting of the alternating current, converts the alternating current into a direct current, and outputs the direct current wherein the control circuit detects a change state of a voltage of the X capacitor C, and controls the discharge such that a charge stored in the X capacitor Cis discharged based on the change state.

Control circuit and power source device

A semiconductor switch control circuit includes: a pulse signal generating part configured to generate a pulse signal which becomes a time reference for performing an ON/OFF control of a semiconductor switch; a drive current generating part configured to generate a drive current based on the pulse signal which the pulse signal generating part generates and to supply the drive current to a gate electrode of the semiconductor switch; a current detecting part configured to detect a drain current or a source current of the semiconductor switch; and a drive current control part configured to have a function of controlling a drive current which the drive current generating part generates based on the pulse signal which the pulse signal generating part generates and the current which the current detecting part detects.

Semiconductor switch control circuit and switching power source device

A power conversion circuit includes: a MOSFET having a super junction structure; an inductive load; and a freewheel diode. A switching frequency of the MOSFET is 10 kHz or more. When the MOSFET is turned off, a first period during which a drain current decreases, a second period during which the drain current increases, and a third period during which the drain current decreases again appear in this order. The freewheel diode is an Si-FRD or an SiC-SBD, and current density obtained by dividing a current value of the forward current by an area of an active region of the freewheel diode falls within a range of 200 A/cmto 400 A/cmwhen the freewheel diode is the Si-FRD, and the current density falls within a range of 400 A/cmto 1500 A/cmwhen the freewheel diode is the SiC-SBD.

Power conversion circuit

A MOSFET used in a power conversion circuit including a reactor, a power source, the MOSFET, and a rectifier element, includes a semiconductor base substrate having an n-type column region and a p-type column region, the n-type column region and the p-type column region forming a super junction structure, the n-type column region and the p-type column region are formed such that a total amount of a dopant in the p-type column region is set higher than a total amount of a dopant in the n-type column region, and the MOSFET is configured to be operated in response to turning on of the MOSFET such that at a center of the n-type column region as viewed in a plan view, a low electric field region having lower field intensity than areas of the n-type column region other than the center of the n-type column region appears.

MOSFET and power conversion circuit

A MOSFET includes a semiconductor base substrate where a super junction structure is formed of an n-type column region and a p-type column region. A total amount of a dopant in the n-type column region is set to a value greater than a total amount of a dopant in the p-type column region. The MOSFET is configured to be operated during a period from a point of time when a drain current starts to decrease to a point of time when the drain current becomes 0 for the first time in response to turning off of the MOSFET such that a first period during which the drain current is decreased, a second period during which the drain current is increased or the drain current becomes constant, and a third period during which the drain current is decreased again occur in this order.

MOSFET

Provided is a power factor correction circuit capable of reducing ringing sound of a transformer produced when an overshoot protection is effected. An output voltage control circuit performs constant voltage-control such that capacitor charge voltage of an output capacitor corresponds to a first voltage value, and when the capacitor charge voltage of the output capacitor reaches a second voltage value higher than the first voltage value, an overvoltage detecting unit detects the second voltage value. Further, a current limiting unit detects a value of a switching current through a switching element, and determines a limiting value of the level of the switching current. Then, the switching current is limited to the limiting value, and when an overvoltage detecting unit detects the second voltage value, a limiting value changing unit causes the current limiting unit to change the limiting value to decrease the value of the switching current.

Power factor correction circuit for providing protection against overvoltage

In a switching power source of a flyback converter system according to the present invention, large electric power can be applied, by reducing loss of a switching element, a coil, and an output smoothing circuit, input voltage is applied to a primary coil of a transformer, and switching drive of the input voltage is carried out by a switching element, so that direct-current electric power is outputted from a secondary coil of the transformer through a rectifier circuit. The power source apparatus includes a trigger-control circuit which detects direct-current output voltage to control an 'on' period, detects that current of the secondary coil becomes zero based on a voltage signal from a control coil, and turns on the switching element, and a timer circuit which is operated according to the voltage signal of the control coil, and gives an ON signal to the trigger-control circuit according to a timing signal.

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Saitama, Japan

Shigeru Hisada