Abstract: A battery charger is provided with a battery charger unit which connects to, and charges a battery. Solar cells are used as the source of power for charging the battery, and connecting parts electrically connect the solar cells and the battery charger unit. The battery charger unit is provided with a solar cell compartment for stowing the solar cells when not in use charging a battery.

Abstract: A temperature compensated photovoltaic module (20) comprised of a series of solar cells (22) having a thermally activated switch (24) connected in parallel with several of the cells (22). The photovoltaic module (20) is adapted to charge conventional batteries having a temperature coefficient (TC) differing from the temperature coefficient (TC) of the module (20). The calibration temperatures of the switches (24) are chosen whereby the colder the ambient temperature for the module (20), the more switches that are on and form a closed circuit to short the associated solar cells (22). By shorting some of the solar cells (22) as the ambient temperature decreases, the battery being charged by the module (20) is not excessively overcharged at lower temperatures. PV module (20) is an integrated solution that is reliable and inexpensive.

Abstract: The present invention relates to a customized storage, high voltage, photovoltaic power station, having at least one photovoltaic solar module and a customized storage device.

Abstract: A photovoltaic (PV) power system having distributed square wave current DC to AC inverters integral with strings of PV cells in a PV array. The PV array is arranged into four quadrants and phase-shifted and summed AC voltages from each quadrant are further summed in a 12-phase to 3-phase transformer to produce a sinusoidal 3-phase AC voltage with a total harmonic distortion of less than 5 percent.

Abstract: It is an object of the invention to accurately detect a defective photoelectric conversion element regardless of the installation place and indicate the corresponding information. The above object can be achieved by a power generating system having a solar cell array constituted by a plurality of parallel-connected solar cell strings each consisting of a plurality of series-connected solar cell modules. The system includes electrical parameter detection units for measuring electrical parameters in solar cell strings, a comparing unit for mutually comparing the detected electrical parameters, and a unit for warning of an abnormality on the basis of the comparison result.

Abstract: The object of the prevent invention is to provide a solar energy system of simple construction capable of utilizing the photovoltaic source always at a high efficiency without being affected by environmental changes or yearly declination of photovoltaic cell, etc.

Abstract: Even when a portion of the incident light plane of a solar cell array is shaded, drastic decrease of photoelectric output is prevented by connecting a plurality of unit cells in parallel and a plurality of such parallel circuits are connected in series to form a solar cell array in which a plurality of unit cells are arranged in rows and columns in the incident light plane of the solar cell such that at least one of the unit cells forming the parallel circuit is arranged in other rows or columns from those of other unit cells forming the parallel circuit.

Abstract: An automatic photovoltaic controller provides a fixed frequency, pulse width modulated charging current to charge and regulate a battery, the duty cycle of the charging current being controlled by the difference between the sensed battery voltage and a desired regulated voltage. Modulation is achieved by controlling the on and off states of plural parallel-connected FET switches placed in series between the photovoltaic array and the battery. The duty cycle is adjustable in discrete steps over the entire range of 0% to 100% and is updated numerous times per second with new battery voltage measurements to provide highly accurate regulation. The charge current pulse rise time is selected to match the response time of the photovoltaic array. The fixed frequency of the charge current is within the preferred range of 100 Hz to 600 Hz to provide sufficient time for the chemical reaction within the battery cells to be substantially completed between charge pulses during the regulation mode.

Abstract: A solar cell system stores electric power generated by solar cells and supplies the electric power to a load. This system includes a solar cell assembly having a capacity for generating electric power in a quantity consumed by the load in one day, the quantity being determined from an estimated quantity of solar radiation available on a rainy or cloudy day, and an electric double layer capacitor having a storage capacity corresponding at least to the quantity consumed by the load in one day.

Abstract: A photovoltaic module that serves as a shingle, tile or other building material that may be placed onto the exterior of a structure. The photovoltaic module generates a voltage when exposed to light and this voltage may be directed onto transmission lines of a power utility and/or into an external battery that may serve as a source of power for the building on which the photovoltaic shingles are laid. The practice of the present invention provides for a variety of mechanical and electrical connectors for securing together the photovoltaic modules and/or for connecting the photovoltaic modules to the exterior structure. Furthermore, the structure of the modules is such that the modules are automatically electrically connected together when laid on the building.

Abstract: Apparatus for converting solar energy to thermal and electrical energy including a substantially unsealed enclosure, an array of photovoltaic cells for converting solar energy to electrical energy located within the enclosure, and a plurality of interconnected heat collecting tubes located within the enclosure and disposed on the same plane as the array of photovoltaic cells for converting solar energy to thermal energy in a fluid disposed within the heat collecting tubes.

Abstract: A dual discharge photovoltaic module responsive to high and low loads. The module includes a first plurality of series connected, high short circuit current cells, and a second plurality of series connected, low short circuit current cells connected in series with the first plurality. A diode is connected in parallel with the second plurality of cells such that current flow through the module when the module is under low load reverse biases the diode so that the module discharges at a low current. When the module is under high load, current flow through the module forward biases the diode and bypasses the second plurality of cells so that the module discharges at a high rate. The module is particularly useful for starting and running an electric motor.

Abstract: This invention relates to a method and apparatus for converting energy to hydrogen gas using an electrolyzer and a metal alloy hydride tank for hydrogen storage, wherein a passive load matching device between the energy source and the electrolyzer maximizes hydrogen output, and the electrolyzer and the metal alloy hydride tank operate at mutually low pressure, near ambient, such that pressurization of the system is not required.

Abstract: In a solar photovoltaic power generation device comprising a plurality of power generation units (31-34) each of which comprises first through n-th generation elements, the first through the n-th generation elements are connected in parallel and have their polarity directed in the same direction. The plurality of power generation units are arranged so that adjacent power generation units have polarities which are opposite to each other. Each of the plurality of power generation units further comprises a plurality of switch elements, each of which has active and inactive states, for connecting the first through the n-th generation elements in series in the active state. The solar photovoltaic power generation device further comprises a power control unit (37) for controlling the plurality of switch elements for placing it into the active state in each of the plurality of power generation units.

Abstract: Circuit arrangement for supplying power to a fan and/or battery from solar energy generator in a motor vehicle. A DC voltage converter using impedance matching between the solar energy generator and the fan or the battery includes a switch that is alternately opened and closed by a pulse-width-modulated operating signal, and is part of the circuit arrangement. To generate the operating signal, a microprocessor, a frequency generator and a pulse width modulator, which is acted on by the output signal of the frequency generator and a control signal of the microprocessor, are provided. These components also are used as components of an actuating device to displace a movable part of a sun roof, a changeover signal switching between use for charging a battery and/or powering a fan and use operating the sun roof. Thus, the circuit arrangement is able to fulfill multiple functions.

Abstract: In an apparatus for shading surfaces, in particular for shading spaces which can be negotiated on foot, or the like, comprising at least a roof sheathing which is stretched on supports or the like carrier elements at a spacing relative to the surface to be shaded, or a corresponding cable netting assembly, as a carrier assembly, on the outside of which are provided photovoltaic elements, the photovoltaic element or solar module is attached to the carrier assembly by intermediate elements with which distortion phenomena of the carrier assembly, which are caused by stretching, can be carried, and external forces can be transmitted to the carrier assembly.

Abstract: An inexpensive method of improving photo-voltaic cell efficiency through preventive maintenance. An electro-static generator places a constant electro-static charge upon the surface of a photo-voltaic cell, or its facial housing. This charge then repels small, unwanted dust and dirt particles. The system also includes an electrical circuit which not only monitors the charge being applied to the cell, but also discharges the electro-static charge when it becomes too great.

Abstract: An object of the present invention is to provide a photovoltaic device and a method of producing the photovoltaic device which can prevent recombination of photo-excited carriers and which permits increases in the open circuit voltage and the carrier range. The photovoltaic device of the present invention has a laminate structure composed of at least a p-type layer of a silicon non-single crystal semiconductor, a photoactive layer having a plurality of i-type layers, and an n-type layer. The photoactive layer has a laminate structure composed of a first i-type layer deposited on the side of the n-type layer by a microwave plasma CVD process, and a second i-type layer deposited on the side of said the p-type layer by an RF plasma CVD process.

Abstract: A vehicle's restraint system for passengers such as airbags, belt tighteners or similar devices to protect the passengers in case of a crash against injury including an electronic sensor circuit for the release of the restraint system, only upon the occurrence of predetermined conditions. An energy supply is provided for supply of the electronic sensor circuit with a proper and set voltage value to be monitored at least from time to time and compared with a reference voltage wherein at least an emergency voltage supply is to be held in a steady state such as at the set voltage value to provide power to electrically ignite a pyrotechnic or propellant charge if triggered by said electronic sensor circuit, in the case that one or more of said predetermined conditions evaluated in said electronic sensor circuit by comparing it with chosen threshold values are fulfilled, indicating that a crash event is detected by an acceleration responsive signal generator in said electronic sensor circuit.

Abstract: The present invention provides a photovoltaic element in which the open-circuit voltage and the path length of holes are improved by preventing the recombination of photoexcited carriers.The p-i-n junction type photovoltaic element is composed of a p-type layer, an i-type layer of a laminated structure consisting of an i-type layer formed by RF plasma CVD on the p-type layer side and an i-type layer formed by microwave (.mu.W) CVD on the n-type layer side, or an i-type layer formed by microwave (.mu.W) plasma CVD on the p-type layer side and an i-type layer formed by RF plasma CVD on the n-type layer side, characterized in that the i-type layer formed by .mu.W plasma CVD is formed by a process in which a lower .mu.W energy and a higher RF energy than the .mu.

Abstract: A photovoltaic (PV) cell with a single pn-junction is disclosed that is capable of functioning as both a current source and a bypass diode. The photovoltaic cell is made of material that has a low bandgap energy, 1.0 eV, or less. One version of the PV cell is formed of a GaSb wafer doped with Te to form an n-region; the Te concentration is between 6 and 10.times.10.sup.17 atoms/cm.sup.3. Multiple PV cells of this invention can be connected in series or in parallel or in tandem in a primary-booster tandem pair to form a circuit without the requirement of protecting the individual cells of the circuit with a separate bypass diode.

Abstract: A method and an apparatus for efficiently controlling the power output of a solar cell array string or a plurality of solar cell array strings to achieve a maximum amount of output power from the strings under varying conditions of use. Maximum power output from a solar array string is achieved through control of a pulse width modulated DC/DC buck converter which transfers power from a solar array to a load or battery bus. The input voltage from the solar array to the converter is controlled by a pulse width modulation duty cycle, which in turn is controlled by a differential signal comparing the array voltage with a control voltage from a controller. By periodically adjusting the control voltage up or down by a small amount and comparing the power on the load or bus with that generated at different voltage values a maximum power output voltage may be obtained.

Abstract: A photovoltaic cell (20) with a single pn-junction (46) is disclosed that is capable of functioning as both a current source and a bypass diode. The photovoltaic cell is made of material that has a low bandgap energy, 1.0 eV, or less. One version of the photovoltaic cell is formed of a GaSb wafer doped with Te to form an n-region (22); the Te concentration is between 3 and 15.times.10.sup.17 atoms/cm.sup.3. Multiple photovoltaic cells of this invention can be connected in series and placed in parallel across a like number of photovoltaic cells (76) that do not function as tunnel diodes in order to form a power-generating array (70). The photovoltaic cells are arranged in tandem pairs so that the photovoltaic cells (76), which are transparent to the light absorbed by the photovoltaic cells (20), overlie the photovoltaic cells (20).

Abstract: A thermostat having a simple battery level detection circuit. The output of an oscillator, having a frequency dependent upon the battery level, is compared to the output of a battery level independent time base. If the two outputs are not in a predetermined relationship, all connected HVAC equipment is shut off.

Abstract: An energy-generating plant including a solar generator, having solar cells, for producing electrical energy. The electrical energy is supplied to a direct current converter, the output power of which may be used to charge an energy storage system, such as batteries. The input resistance of the direct current converter is adapted, such as by a microcomputer, to the maximum power point (MPP) of the solar generator, the MPP being dependent upon the solar insolation and the temperature of the solar cells. At start up of the plant, or when there is a change of power at the output of the direct current converter, a search process is carried out to attain the MPP of the solar generator. The energy storage system may be used to energize an electric motor for driving the propeller of a ship.

Abstract: Transparent pane for vehicles, in particular, a transparent cover for sliding roofs, lifting roofs and the like, with a transparent outer layer and a solar laminate lying flat against the inside of this outer layer. The active part of the solar laminate is formed of a first subsection lying in the outer edge area of the pane which is made of crystalline semiconductor material, and a second subsection that is made of an amorphous semiconductor material.

Abstract: The instrumentation package is transportable to remote sites solely by a light helicopter. Accordingly, three skids are provided, each of which weighs less than 1,200 pounds. An instrument skid comprises a generally, horizontally disposed frame having jacks mounted on it for leveling. Instruments and control elements are also mounted to the frame, preconnected at the factory, and protected from weather. A separate battery skid is provided which is mounted on the instrument skid at the site. A solar array skid, the sloping roof of which comprises solar cells is separately transportable by helicopter to the site and is lowered onto and fastened to the instrument skid. The instrument skid preferably has a self-contained generator mounted thereon when it is transported to the site. An instrument and antenna mounting tower for telemetry, if desired, is broken down and carried within the solar array skid to the site and then mounted on the rear of the instrument skid and tied to the solar array skid.

Abstract: A satellite adapted to be stabilized in terrestrial orbit by rotation about an axis oriented at least approximately NORTH-SOUTH has on its external wall a solar generator composed of a plurality of columns of solar cells divided into groups adapted to supply at least one given electrical voltage. In each of a plurality of groups equi-angularly distributed in the circumferential direction, the cells straddle two columns electrically connected by at least two electrical connections forming with the group(s) to which the connection belong an electrical loop. The clockwise or counterclockwise direction of current flow is the same for least the majority of the electrical loops and is so chosen that, at any time, the loops which are illuminated at this time by the Sun, by virtue of interaction with the terrestrial magnetic field, produce a compensating torque in the opposite direction to the solar radiation pressure torque.

Abstract: A self-sustaining power module (10) that combines the technologies of radioactivity with photovoltaic cells (12) to produce an electrical power supply having a useful life of over ten years. The radioactive source is a tritium capsule (22) that interfaces with the receptor surface of the photovoltaic cell (12). The capsule (22) has inside surfaces that are coated with a phosphor and is filled with tritium gas (26). The tritium gas produces beta particles that bombard the phosphor (18) causing the phosphor to luminesce and produce photons. The photons, in turn, strike and cause the photovoltaic cell (12) to generate a current flow that is then applied, via a pair of electrtodes (30), (32), to an external load. Also disclosed is a power pack (40) that houses a plurality of power modules (10). The power pack includes provisions that allow the power modules (10) to be electrically interconnected to provide various series, parallel and series-parallel power output combinations.

Abstract: A semiconductor device includes laminated photoelectric conversion elements each having a semiconductor thin film carrying out the photoelectric conversion, the respective semiconductor thin film having a relationship L.ltoreq.1/.alpha.(.lambda.) when incident light is of a wavelength .lambda., the semiconductor thin film is of an absorbtion coefficient .alpha.(.lambda.) with respect to the light of the wavelength .lambda. and the carrier collecting length is L, whereby the optimum combination of the incident light wavelength and the sensitivity of the device can be obtained to realize a high photoelectric conversion efficiency.

Abstract: Electrical power transfer apparatus (40) for controlling the supply of electrical power fram an array of photovoltaic cells (41) to an electrical load (46) by means of a switching power converter (45). The switching power converter (45) is controlled by a regulator (58) to maintain the output voltage from the photovoltaic array (41) at a fixed fraction of the open circuit voltage of the photovoltaic array (41), the fixed fraction suitably being between 0.75 and 0.8, whereby the power transfer from the photovoltaic array (41) is maximized. The open circuit voltage of the photovoltaic array (41) is sensed by inhibiting the operation of the switching power converter for short sampling periods at regular intervals, and allowing a capacitor (52) to charge to the voltage of the open-circuited photovoltaic array (41) during the sampling periods.

Abstract: A solar power system supplying A.C. voltages at 60 Hz as required for irrigation control with frequency precision and voltage levels in accordance with specifications for off-the-shelf irrigation timers and controls.

Abstract: In order to provide the required electric power uninterruptedly to an electrical or electronic consuming device (M) powered by solar cells (1, 2, 3, 4), the supply of power to the consuming device must be assured even under inadequate illumination conditions and/or during brief failures of the solar collector (S), an electronic system is proposed wherein a control circuit (RK) is provided between the solar collector (S), the consuming device (M), and an electrical energy storage device (C1). The control circuit (RK) functions at least as a connecting and commutating switching device which, subject to the priority of maintaining the operational readiness of the consuming device (M); provides various interconnections of the solar collector (S), the storage device (C1), and the consuming device (M). The control circuit (RK) makes these various connections in dependence on (1) the voltage (U.sub.S) at the solar collector (S), (2) the voltage (U.sub.

Abstract: A solar battery system characterized by at least one solar cell for converting light energy to electrical energy which is stored in the system is provided. The solar cell is formed of a semiconductor selected from the group consisting of single crystal, polycrystalline and amorphous substrates and is coupled in parallel to an energy-storage capacitor, which capacitor is also connected in parallel with a loading circuit. The capacitor is formed of compressed particles of activated carbon which stores electrical energy charged to it by the solar cell at a selected voltage level. A diode is coupled in series to an output terminal of said solar cell to prevent the flow of a reverse current to the solar cell during discharge of the capacitor to the loading circuit.

Abstract: A photoelectric converting circuit including a light-receiving element which produces a current signal corresponding to the amount of light incident upon it and a current-to-voltage converting circuit which converts the current signal to a voltage signal. The circuit is characterized in that the current signal is supplied to the current-to-voltage converting circuit through an active circuit which exhibits a low input impedance. In preferred embodiments, the active circuit is a common-base transistor circuit in which an emitter current is supplied to the light-receiving element and a collector voltage is outputted as an output signal.

Abstract: A switching network for improving the conversion efficiency of a photovoltaic power supply comprises a variable coupling circuit for coupling an array of photovoltaic cells to a load resistance. The combined effective impedance of the network and load is varied to match the value required for maximum output power. A switching transistor (22) which connects the source module (20) to the load (30) is pulse-width modulated with a variable duty cycle determined by the control signal from the sensor circuit. A photovoltaic cell (32) similar to those comprising the photovoltaic power module (20) is used to track variations in the ambient light intensity. The open-circuit voltage of a sensor cell (32) is used to determine the proper value of duty cycle required for maximum power transfer. The output voltage of the module (20) is sampled and compared with the proper value to produce a control signal.

Abstract: A controlled zone defrosting system is provided for disbursing electrical energy, according to predetermined priorities, to a plurality of defrosting devices, formed of an electrically conductive glass coating material, in an automobile or the like. The defrosting devices could, for example, be effectively located to melt ice formed on such areas as the driver and passenger sides of a windshield, a rear window, etc. The disbursement of electrical energy may, in addition to being dependent on preselected priorities, be made dependent on a number of factors such as time, temperature and the remaining amount of energy. The electrical energy may be supplied by an associated automobile's battery, an independent battery, or an electrical energy generating mechanism such as a photovoltaic device. Available remaining electrical energy may be monitored and, as it is diminished, be disbursed only to zones given top priorities.

Abstract: This invention relates to a battery charger which supplementally charges a secondary battery such as a battery and so forth in an automobile with use of a solar cell in which a diffusion-blocking layer is formed between a semiconductor and a reverse electrode for the purpose of preventing deterioration of a semiconductor layer, and in which electric potential of the secondary battery can be measured and displayed, and in which the solar cell can be securely provided in a compartment of an automobile in such a manner that the solar cell always faces sunbeams, and which can be freely attached and detached.

Abstract: A powder supply device with a solar cell is made up of a solar cell, a seconary battery, and a voltage control unit. The voltage control unit controls the output voltage of the solar cell, and produces first and second output voltages. The first output voltage is for charging the secondary battery. The second output voltage is for driving a circuit, such as the logic circuit of an electronic calculator.

Abstract: A solar-powered beacon comprises a water-tight caisson housing a battery for storing electricity produced by solar cells atop the beacon. An electronic circuit within the caisson controls operation of the beacon. The caisson material acts as a heat sink for the solar cells, and insulation is provided below the cells to further protect the electronic components.

Abstract: A system for feeding and controlling low intensity obstruction lights, involving low power drain especially in radio stations powered by solar cells includes:a sub-system which not only generates the energy necessary to feed the obstruction light, but also detects solar intensity;a control sub-system which delivers energy to the obstruction lights, triggered in correspondence to a light threshold, generates indicator signals on the operating state of the main on/off switch and the power circuit breaker and generates a lamp failure control for telemetering purposes and fault controls for the individual obstruction lights for local displaying purposes; and a low luminous intensity and low power drain lighting sub-system.

Abstract: In order to avoid unwanted degradation in no-load operation of solar cell modules composed, in particular, of amorphous silicon, an internal load resistor is integrated in the module and is connected across the output terminals during no-load operation of the module. Disconnection of the resistor during load operation occurs either in a mechanical manner by way of a mechanical switch integrated in a plug extending to the load or occurs automatically by way of an electronic switch. The arrangement is employed in operation of solar cell modules for systems having a non-continuous power consumption such as, for example, appliances in mobile homes, mountain chalets and the like.

Abstract: A solar cell array is disclosed having a support structure, cover, and mechanically joined solar cell panels. Each panel, or group of panels, is electrically connected across a separate battery and a diode is provided to provide separate charging of each battery and to prevent flow of current to the solar cells from the batteries.

Abstract: A solar energy electric generating system for space vehicles is provided which directly generates alternating current from ambient light without the use of inefficient power conversion. Light incident to photocell arrays is mechanically or electrically gated to produce fluctuating DC. A number of transforming devices are provided to convert the fluctuating direct current to alternating current. By varying the frequency and duty cycle of the pulsing output voltage, frequency and phase relative to some reference may be controlled. Additionally, direct current may also be produced efficiently from the same photocell arrays. A closed-loop system is provided for regulation. The rotational torque produced by a rotating shutter version may also be used, under inertial navigation control, to provide a rotational torque for vehicle positioning.

Abstract: A direct coupled FET logic (DCFL) circuit element has an active FET with source connected to a low reference voltage and drain connected through a pull-up FET to a higher reference voltage. An input is applied to the gate of the active FET and the output is taken from its drain, the pull-up FET having its gate connected to its source. In depletion mode configuration, a photodiode is connected to the gate of the active FET, the photodiode energizable to downwardly shift the gate voltage. In enhancement mode configuration, a photodiode is connected between source and gate of the pull-up transistor and is energized to shift the gate voltage upwardly. The photodiodes are integrated with the active and pull-up FETs and are energized by light or decay radiation.

Abstract: An optical power distribution system for supplying power to low power electrical devices includes an electrically powered source of optical radiation the output of which is applied to a photovoltaic cell array arranged on the device to be powered and electrically connected thereto.

Abstract: A photovoltaic power supply and battery charging system comprises a photovoltaic solar energy power supply panel connected through a blocking diode to a secondary storage battery which, in turn, is connected to a suitable load. A temperature sensitive reference voltage is supplied to one input of a voltage comparator, the other input to which is connected to the battery and thereby varies in accordance with the variations of charge on the battery. A short circuit shunt switch is connected directly across the photovoltaic panel; and this shunt switch is opened for varying periods of time by the output of a variable pulse width generator. The pulse width generator, in turn, is connected to and is controlled by the output of the voltage comparator to produce pulses of different widths. The charging current supplied to the battery then occurs in the form of high current pulses of varying widths depending upon the charge state of the battery.

Abstract: A rechargeable battery array comprises a plurality of rechargeable battery cells (10)-(16) connected in series, and in equal plurality of charging sources (18)-(24) connected in series. Corresponding terminals of corresponding battery cells and charging sources are interconnected. The internal resistance of each of the charging sources is matched to the internal resistance of each battery cell. The configuration provides substantially faster charging of the battery cells than is possible using conventional battery cell array charging configurations. The invention is particularly well suited to photo-voltaic charging systems.

Abstract: An energy storage system for a spacecraft is provided which employs a solar powered flywheel arrangement including a motor-generator which, in different operating modes, drives the flywheel and is driven thereby. A control circuit, including a threshold comparator, senses the output of a solar energy converter, and when a threshold voltage is exceeded thereby indicating the availability of solar power for the spacecraft loads, activates a speed control loop including the motor-generator so as to accelerate the flywheel to a constant speed and thereby store mechanical energy, while also supplying energy from the solar converter to the loads. Under circumstances where solar energy is not available and thus the threshold voltage is not exceeded, the control circuit deactivates the speed control loop and activates a voltage control loop that provides for operation of the motor as a generator so that mechanical energy from the flywheel is converted into electrical energy for supply to the spacecraft loads.

Abstract: An output voltage of a solar cell is supplied to a voltage converter. The voltage converter converts the input voltage into a predetermined voltage, and supplies it to a capacitor. The capacitor is charged by the output current of the voltage converter. The capacitor has a relatively large capacitance. A second voltage converter converts an input voltage from the capacitor into a voltage which is lower than the charged voltage of the capacitor and higher than a minimum operating voltage of a load. The load performs a predetermined operation using the output voltage of the second voltage converter.