Hitachi, Ltd.

Renesas Technology Corp.

Hitachi Media Electronics Co., Ltd.

Takashi Sase

Akihiko Kanouda

Kazuo Kato

Fumio Murabayashi

Mutsumi Kikuchi

Atsuo Watanabe

Koji Tateno

Shinichi Yoshida

Yosuke Tsuyuki

Masatsugu Amishiro

Hideo Sato

Kenji Tabuchi

Yosuke Kawakubo

Katsunori Hayashi

Tomohiro Tazawa

Kouji Tateno

Takashi Hotta

Ryotaro Kudo

Kenichi Onda

Hiroyuki Shoji

Kozaburo Kurita

Takuya Ishigaki

Kenkichi Yamashita

Ichiro Ikushima

Tomohiko Douken

Kazuo Katou

Ikuho Horinaka

Fumio Tajima

Takao Sasayama

Noboru Akiyama

Hirokazu Aoki

Takeshi Hirayama

Tadahiko Hashimoto

Kazuyoshi Takizawa

Kikuo Tomita

Yoshiyuki Nihashi

Muneo Chiba

Shuzo Oshima

Syuichi Senda

Kazuo Katoh

Tetsuya Nagayama

A power-supply unit including a transformer, a full bridge circuit having four arm switches on a primary side of the transformer, a rectifier and smoothing circuit including two synchronous rectifier switches on a secondary side of the transformer, a choke coil, and a capacitor, an output terminal in the rectifier and smoothing circuit, a control circuit controlling ON/OFF of the four arm switches of the full bridge circuit and the two synchronous rectifier switches of the rectifier and smoothing circuit, a resonant inductor including a leakage inductor component and a parasitic inductor component on the primary side of the transformer, and a resonant capacitor, and in which the control circuit includes a timing variable unit which varies switching timings of the two synchronous rectifier switches of the rectifier and smoothing circuit based on an output current flowing in the output terminal provided in the rectifier and smoothing circuit.

Power-supply unit, hard-disk drive, and switching method of the power-supply unit

A power supply device includes two buck converters, having a coupling inductor Lo composed of two mutually-coupled inductors L, L, and a output capacitor Co, wherein of the two buck converters, a first buck converter is operated during a positive half-cycle period of an AC input voltage, and a second buck converter is operated during a negative half-cycle period of the AC input voltage, to obtain a DC output voltage at both ends of the output capacitor Co from the AC input voltage, is provided. Herewith, is provided the power-supply device using the buck converter, which can be reduced in the number of components and produced in a low cost without a diode bridge.

Supply device, and LED lighting equipment using the same

A power converter includes a first inductor, a rectifier arm, a first switch arm including a first and second switch circuits, a second switch arm including a third switch circuit and a first capacitor, a LC serial circuit, a Transformer, a rectification and smoothing circuit connected to secondary winding of the transformer, and a control circuit to perform on-off control of the three switch circuits. The rectifier arm, the first and second switch arms and the LC serial circuit are connected in parallel with each other. The LC serial circuit and primary winding of the transformer are connected. AC power supply is connected to the rectifier arm via the first inductor. The control circuit includes an output voltage control circuit to control output voltage at specific setting value, an intermediate voltage control circuit to control intermediate voltage at specific setting value, and a power factor correction control circuit.

Power converter, control method of power converter, and hard disk drive

To provide aAdigital control switching power-supply deviceis provided which iscapable of suitably achieving fast transient response at the time of a sudden load change. In parallel with normal digital signal processing means that outputs a PWM pulse signal having a desired duty, transient variation detection means composed of a CR filter provided across an output inductor and a window comparator is provided in preparation for a sudden load change. If a sudden decrease in load is detected, a PWM pulse signal having a duty of 0% is forcedly output, and if a sudden increase in load is detected, a PWM pulse signal having a duty of 100% is forcedly output.

Digital control switching power-supply device and information processing equipment

A first-order feedback control power supply apparatus being arranged in such a manner that when the apparatus is driven under light load condition, a current flowing through an inductor is detected by employing a second CR smoothing filter; when the present load condition is judged as a light load condition based upon the detected inductor current, both upper-sided/lower-sided power MOSFETs and a PWM oscillator are turned OFF so as to be brought into sleep states; when an output voltage of the power supply apparatus is lowered and the lowered output voltage reaches a lower limit threshold of a transient variation detecting circuit, the upper-sided power MOSFET is turned ON to recover the output voltage; and when the output voltage of the power supply voltage reaches a predetermined voltage, the upper-sided power MOSFET is turned OFF so as to be again brought into the sleep state.

Power supplying apparatus including a pulse-width modulation oscillator and smoothing filters

Zero volt switching during a light load is performed in such a manner that through an ON/OFF control of switches provided for a full bridge circuit and the synchronous rectifier switches in a rectifier and smoothing circuit, a resonant peak voltage necessary for the zero voltage switching determined by the output current flowing to output terminals, a resonant inductor and a resonant capacitor capacitance is ensured so that an energy accumulated in the rectifier and smoothing circuit is returned to the full bridge circuit so as to act as equivalent as when the output current is increased and to increase the current flowing through the full bridge circuit.

Power supply unit, hard disk drive and method of switching the power supply unit

To provide a digital control switching power-supply device capable of suitably achieving fast transient response at the time of a sudden load change. In parallel with normal digital signal processing means that outputs a PWM pulse signal having a desired duty, transient variation detection means composed of a CR filter provided across an output inductor and a window comparator is provided in preparation for a sudden load change. If a sudden decrease in load is detected, a PWM pulse signal having a duty of 0% is forcedly output, and if a sudden increase in load is detected, a PWM pulse signal having a duty of 100% is forcedly output.

A first converter circuit converts a state signal, whose level is constant or slowly varies during a predetermine period of time, into a pulse signal to allow the signal to propagate across an electrically insulating area. A second converter circuit converts the pulse signal, which has propagated through an insulating circuit, into the original state signal or a signal having the same characteristics as the original state signal.

Interface device and information processing system

A power-supply device including a marginal check voltage setting circuit that is easily adaptable to downsizing of the device and to configuration using ICs. The power-supply device of this invention includes a marginal check voltage setting circuit that sets a desired marginal check voltage, an error amplifier that delivers output of an error signal, a pulse width modulation oscillator that modulates the pulse width of the output from the error amplifier, a driver circuit that generates driving signal from the pulse signal originating from the pulse width modulation oscillator, and a pair of power semiconductor switching devices that work to step down the input voltage and generate an output voltage based on the driving signal. Furthermore, the power-supply device is also provided with an over-voltage detection circuit and a power-good circuit both circuits being positioned at the output terminal of the marginal check voltage setting circuit.

Marginal check voltage setting means built-in power-supply device

An over-current detection circuit using the ON-voltage of a main MOSFET is provided, which is resistant to process variations of a main MOSFET and is not easily influenced by switching noise. Separately from a main MOSFET (Q), a sense MOSFET (Q) whose size is 1/m of the main MOSFET is provided and it is caused to be normally on. A DC ON-voltage generated when a current that is 1/m of an over-current value is caused to flow through the sense MOSFET is obtained as a reference voltage for over-current setting. The ON-voltage when the main MOSFET is on is sampled and held, and it is obtained as a DC voltage. These DC voltages are compared in a comparator (COMP).

Over-current detection circuit and method for power-supply device

In a switching power supply apparatus for performing a switching control of a power MOS transistor that flows current to a coil and converting input voltage into output voltage, even if there occurs offset voltage in a current sensing operational amplifier, source potential of a current sensing MOS transistor is precisely kept at source potential of a low side power MOS transistor. For example, an offset cancel capacitor is arranged at an inverting input terminal of the current sensing operational amplifier, and voltage in the direction to offset the offset voltage occurring in the operational amplifier is charged to this capacitor.

Switching power supply

A semiconductor device capable of achieving downsizing without reducing the power supply efficiency and capable of reducing switching noises and a memory card using the same are disclosed. The device comprises a plurality of stages of voltage booster circuits for potentially raising a power supply voltage up to a final output voltage, a voltage control unit for controlling an output voltage at a nearby location of the final stage, and one or more internal elements to which the final output voltage is supplied. A primary voltage booster circuit at the first stage includes an inductance element, a switching element, a diode and a driver circuit. At a metal core part of the inductance element, a metal wiring line is used, which was formed by use of a fabrication process of semiconductor integrated circuits, while employing for its core part an inter-wiring layer dielectric film that was formed using the fabrication process. In addition, the switching element and the diode are arranged so that portions thereof are disposed beneath the inductance element.

Semiconductor device and memory card using same

The object of the invention is to compensate an effect of a voltage drop emerging in output voltage by the equivalent series resistance of a power output filter in a power-supply device. To achieve the object, a power-supply device wherein the power output filter that passes output power and first and second filters provided separately from the power output filter are provided, the first filter provided separately and one input terminal of an error amplifier are connected, new reference voltage acquired by adding differential voltage between the output of the second filter provided separately and the output of the power output filter to reference voltage is input to the other input terminal of the error amplifier and an output signal is fed back to the error amplifier is provided. According to the power-supply device, a voltage drop by equivalent series resistance emerging the output voltage of the power-supply device can be compensated.

Power-supply device and hard disk drive using same

A power supply driver circuit with low power losses and desired response characteristics with respect to changes in output and its miniaturization is provided. In a driver IC constituting a switched-mode power supply equipment controlling the switching, by pulse width modulation, of first and second power transistors passing a current in a coil, and outputting a voltage bucked or boosted from an input voltage, current sensing with desired responsiveness is enabled by providing a switching transistor between an inverted input terminal and a non-inverted input terminal of an operational amplifier, preventing, while the second power transistor is ON, the generation of a potential which is undefined when first power transistor is ON, i.e. when the second power transistor is OFF, and maintaining a node potential in a state in which the potential is well defined.

Power supply driver circuit

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Hitachi, Japan

Takashi Sase