Abstract: A unidirectional DC-DC converter which has a simple control circuit without using multiple insulated power supplies or a transformer, uses an auxiliary inductor of a comparatively small capacitance, reduces the size and weight of the converter, and has a very great capacitance without switching of supply current. For example, a unidirectional DC-DC converter equipped with main IGBT101 which supplies and shuts off current for first inductor 108a and diode 107 which discharges energy from main inductor 108a to an the output. The DC-DC converter is further equipped with auxiliary IGBT104 which applies current to back-to-back-connected diode 102 by using energy stored in auxiliary inductor 108b which is magnetically coupled with main inductor 108a. This applies current to the back-to-back-connected diode in a short period including a time period in which the first switching element is turned on and accomplishes ZVZCS.

Abstract: A soft switching DC-DC converter is provided which includes circuitry for both a buck converter and a boost converter. The buck converter circuitry and the boost converter circuitry share a common transformer including a primary coil and first and second secondary coils. A first switching element is coupled to a first capacitor to provide the buck converter operation while another switching element is provided to provide the boost converting operation. The primary coil of the transformer is commonly used as a choke coil by both the buck converter and the boost converter. In this way, size and cost reduction can be obtained.

Abstract: A DC-DC converter, which supplies a drive power to a display apparatus, includes a plurality of insulated transformers, a resonance capacitor, and a resonance coil. Primary coils of the plurality of insulated transformers, the resonance capacitor, and the resonance coil are connected in series to form a current resonance circuit, and secondary coils of the plurality of insulated transformers are connected in parallel.

Abstract: In a circuit board disposed in parallel to a fixing plane, a guard spacer (abutting member) is disposed on a multi-layer printed circuit board on the side of the fixing plane to suppress deformation of the multi-layer printed circuit board to prevent short circuit if an impact is applied to the circuit board. The guard spacer may be a dummy electronic component or a plate member. An image display using the circuit board is also disclosed.

Abstract: A fuel cell 1 and an electric double-layer capacitor 2 are parallelly arranged for a power supply. A DC/DC converter 3 steps up voltage of the fuel cell 1 and the electric double-layer capacitor 2, to thereby output power. An output switch 5 is disposed on an output pathway of the DC/DC converter 3. By controlling the output switch 5 with a control IC 4, output power can be switched on and off. When there is a fuel shortage or abnormality in the fuel cell 1, the control IC 4 controls the output switch 5, to thereby intermittently alter the output power. With this configuration, when the power supply is used for a mobile telephone as a portable electronic device connected thereto, a user can confirm whether there is a fuel shortage or a fuel cell abnormality by checking of blinking state of a charge pilot lamp of the mobile telephone.

Abstract: A DC backup power supply system having a battery a charge-discharge circuit for charging and discharging a power between the battery and a DC line and a control circuit for controlling the charge-discharge circuit, wherein the battery has a number of battery cells and cylindrical portions of the battery cells are laid on an approximately horizontal plane.

Abstract: A buck-boost converter of an H bridge type having a function for initially charging a smoothing output capacitor without a relay and a rush current preventing resistance. A compact and flat power supply is attained by employing a current critical mode H bridge system for a PFC converter and providing a function of initially charging a smoothing output capacitor to a converter circuit.

Abstract: In order to provide a fuel cell apparatus with an effective energy consumption by selecting a suitable fuel cartridge mounted on the apparatus, the present invention provides a fuel cell apparatus comprising at least two fuel storage sections for storing fuel for power generation, wherein at least one of the storage sections is selected and used, while the fuel cell is in service.

Abstract: A switching power supply capable of correcting a power factor without using a shunt resistor is provided. The switching power supply includes a rectifier for rectifying an AC power supply, boosting means including a power MOSFET for boosting an output of the rectifier, a smoothing capacitor for smoothing an output of the boosting means, voltage-dividing resistors for detecting a voltage between main terminals of the power MOSFET, a switch for selecting only the voltage by which the power MOSFET is in on-state from voltages detected by the voltage-dividing resistors, an amplifier for amplifying the voltage selected by the switch and outputting the same as a current corresponding value of a current flowing in the power MOSFET, voltage-dividing resistors for detecting the output voltage, and driving means which form a pulse signal based on the current corresponding value and the output voltage for driving the power MOSFET by the pulse signal.

Abstract: A DC backup power supply system having a plurality of loads to which AC from a commercial power source is supplied, and DC power storage means for supplying DC power to the plurality of the loads at the time of a power outage of the commercial power source, said DC backup power supply system including: a control circuit having a first DC backup output for supplying a power from the DC power storage means to the plurality of the loads, including a specific load, only during the power outage of the commercial power source, and a second DC backup output for continuously supplying a power from the DC power storage means to the specific load regardless of the power outage of the commercial power source or sound operation thereof, the control circuit supplying the respective powers from the same DC power storage means to the first and second DC backup outputs.

Abstract: A battery and a DC-to-DC converter are contained in a battery pack. When the battery pack is connected to a load by means of a connector and an output voltage reference value, corresponding to the power supply voltage of the load, the output voltage of the battery is converted according to the output voltage reference value by the DC-to-DC converter. The output voltage reference value is set by an output voltage reference value output means in the connector. Furthermore, the converted voltage is supplied to the load via an output voltage line.

Abstract: An uninterruptible power system for inputting an AC power, converting the AC power into a desired power, supplying the desired power to a load, and upon occurrence of an AC failure, converting a DC power from energy accumulation means into the desired power and supplying the desired power to the load, wherein the DC power from said energy accumulation means is passed through two serially connected boost means, and thereafter the power is converted into the desired power to be supplied to the load, wherein first boost means of the two serially connected boost means, which is nearer to the energy accumulation means, raises the DC electric power from said energy accumulation means to supply second boost means of the two serially connected boost means when supply of electric power is interrupted, and lowers inputted electric power for charging the electric accumulation means during an ordinary operation.

Abstract: In the case where there coexist general loads requiring backup only for a short duration and a specific load requiring backup for a longer duration, uninterruptible power with higher reliability is supplied to the specific load with the adoption of a simple configuration. A DC backup power supply system comprises an AC/DC converter for normally supplying DC power to loads in while (the general loads and the specific load, included), and a control circuit for supplying DC output backing up the loads in whole for relatively short time only from a battery at the time of a power outage, while supplying DC output backing up the specific load, such as a cache memory and so forth, for relatively long time. Thus, it is possible to implement an uninterruptible power supply system small in size and low in cost, provided with a function for proper use depending on a prevailing situation.

Abstract: To provide a smaller and more efficient switching power supply 10.

Abstract: 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 (Q1), a sense MOSFET (Q3) 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).

Abstract: 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.

Abstract: A buck converter circuit and a boost converter circuit, which co-use a main inductor, are connected in series with each other between a DC power-supply and a DC load between output terminals a-b of a rectifier circuit. Moreover, utilizing energy accumulated into first and second auxiliary inductors which are loosely coupled to the main inductor magnetically, a current is flown through diodes during a short time-period including a point-in-time at which main switching elements of the buck and boost converter circuits are to be turned ON. Here, the diodes are connected in inversely parallel to the main switching elements.

Abstract: 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.

Abstract: A unidirectional DC-DC converter which has a simple control circuit without using multiple insulated power supplies, uses an auxiliary inductor of a comparatively small capacitance, reduces the size and weight of the converter, and has a very great capacitance without switching of supply current. A unidirectional DC-DC converter equipped with main IGBT101 which supplies and shuts off current for first inductor 108a and diode 107 which discharges energy from main inductor 108a to an output, wherein the DC-DC converter is further equipped with auxiliary IGBT104 which applies current to back-to-back-connected diode 102 by using energy stored in auxiliary inductor 108b which is magnetically coupled with main inductor 108a. This applies current to the back-to-back-connected diode in a short period including a time period in which the first switching element is turned on and accomplishes ZVZCS.

Abstract: A control method of a power source system having at least two kind of power supply, such as a fuel cell and an auxiliary power supply and supplying power to electronic devices, the fuel cell characteristics being recovered by increasing the fuel cell output voltage.