Hitachi, Ltd.

Other

Hitachi Computer Peripherals Co., Ltd.

Hitachi Maxell, Limited

Hitachi Maxwell, Ltd.

Ryouhei Saga

Kenichi Onda

Norikazu Tokunaga

Akihiko Kanouda

Takeshi Onaka

Satoru Masuyama

Katsunori Hayashi

Morinobu Endo

Masato Isogai

Mikiya Nohara

Hiroshi Kimura

The present invention reduces the capacity of the AC-DC converter for the peak load and realizes low price and reduction in the volume of the power unit. The apparatus built-in backup power supply has the peak cut function for sharing a part of the load current at the time of peak load from the secondary battery. The two-way DC-DC converterand the secondary batteryare installed on the DC output side of the AC-DC converterand a current larger than a predetermined peak cut level is discharged from the secondary batteryat the time of peak load. Further, when the load is less than the predetermined cut level, the secondary batteryis charged from the AC-DC convertervia the two-way DC-DC converter. Furthermore, a most suitable peak cut level according to the SOC of the secondary battery and load pattern is automatically set and dynamically changed.

Backup power supply

Apparatus built-in backup power supply system has a 'peak cut' function for sharing a part of the load current at the time of a peak load using a secondary battery. For this purpose, a two-way DC&#x2014;DC converterand the secondary batteryare installed on the DC output side of the AC-DC converterand that portion of the load current that exceeds a predetermined peak cut level is discharged from the secondary batteryduring peak loading. When the load is less than the predetermined cut level, the secondary batteryis charged from the AC-DC convertervia the two-way DC&#x2014;DC converterA suitable peak cut level is determined according to the state of charge of the secondary battery and load pattern, and is changed dynamically.

A DC power supply device comprises an AC/DC converter , a DC/DC converter , and a DC converter 3 converting DC power from a battery to DC voltage for connecting to output terminals of the AC/DC converter. The DC power supply device is provided with a controlling circuit which observes a charging control level and a load sharing level, impresses a charging command on a UPS controlling part controlling the DC converter, and simultaneously provides a PFC controlling part controlling the AC/DC converter with a current command when a voltage level is less than the charging control level, stops only the charging command when the voltage level is more than the charging level and less than the load sharing level, and provides the UPS controlling part and the PFC controlling part with current commands when the voltage level is more than the load sharing level. The AC/DC converter and the DC converter supply power in parallel when a load is more than a prescribed value, and the DC converter supplies power as a backup when a trouble is present in an AC power input.

DC power supply device

A DC-DC converter is provided with a calculation circuit which estimates current flowing through a reactor in a control circuit for controlling a switching element and a circulation use element, and the switching element and the circulation use element are controlled by making use of the calculated reactor current value. Thereby, a DC-DC converter which operates in a high efficiency and with low ripple even during a light load condition and realizes a high response performance during load variation is provided.

Synchronized rectifier voltage step down DC-DC converter and control circuit therefor

A voltage regulator module includes a power supply circuit for supplying power to an integrated circuit, the power supply circuit including semiconductor switching devices and a drive circuit for driving the semiconductor switching devices; and charge storage means for smoothing an output of the power supply circuit, wherein charge storage unit having a smoothing capacitor includes an electric double-layer capacitor, wherein the electric double-layer capacitor includes a plurality of positive electrode terminals and a plurality of negative electrode terminals, and wherein the plurality of positive electrode terminals and the plurality of negative electrode terminals are disposed on a surface identical to a surface of the electric double-layer capacitor.

Voltage regulator module for micro processor and CPO using a super capacitor

A voltage regulator module includes a power supply circuit for supplying power to an integrated circuit, the power supply circuit including semiconductor switching devices and a drive circuit for driving the semiconductor switching devices; and charge storage means for smoothing an output of the power supply circuit, wherein charge storage unit having a smoothing capacitor includes an electric double-layer capacitor, wherein the electric double-layer capacitor includes a plurality of positive electrodes terminals and a plurality of negative electrode terminals, and wherein the plurality of positive electrode terminals and the plurality of negative electrode terminals are disposed on a surface identical to a surface of the electric double-layer capacitor.

DC-DC step-down converter with super capacitor

A DC power supply device comprises an AC/DC converter , a DC/DC converter , and a DC converter converting DC power from a battery to DC voltage for connecting to output terminals of the AC/DC converter. The DC power supply device is provided with a controlling circuit which observes a charging control level and a load sharing level, impresses a charging command on a UPS controlling part controlling the DC converter, and simultaneously provides a PFC controlling part controlling the AC/DC converter with a current command when a voltage level is less than the charging control level, stops only the charging command when the voltage level is more than the charging level and less than the load sharing level, and provides the UPS controlling part and the PFC controlling part with current commands when the voltage level is more than the load sharing level. The AC/DC converter and the DC converter supply power in parallel when a load is more than a prescribed value, and the DC converter supplies power as a backup when a trouble is present in an AC power input.

In a voltage drop chopper type DC-DC converter, in an intermediate load area, a pulse train having a low peak value in the neighborhood of the threshold voltage is applied to a power MOSFET, whereby the power MOSFET is given a high ON resistance and turned on. By doing so, the output voltage is controlled by a PAM (pulse amplitude modulation) switch system for reducing the peak value below the supply voltage.

DC-DC converter with switchable control mode

A power supply apparatus includes a semiconductor switching device for outputting power and a control circuit for controlling the on/off operation of the semiconductor switching device. The control circuit includes a circuit for applying, when turning on the semiconductor switching device, a first control signal corresponding to the difference between the output voltage of the power supply apparatus and a first reference value to the semiconductor switching device in accordance with the increase in the output voltage from the power supply apparatus thereby to operate the semiconductor switching device in a non-saturated area, so that the semiconductor switching device is turned on gradually.

Growing community of inventors

Takasaki, Japan

Ryouhei Saga