Abstract: In accordance with an embodiment, a power supply may include a filter stage coupled to an input terminal of a discharge circuit and a supply capacitor coupled to an output terminal of the discharge circuit. In accordance with another embodiment, a method for discharging at least one capacitor includes discharging the at least one capacitor in response to a signal at the input terminal of the discharge circuit being different from a reference signal.

Abstract: A power supply includes an input filter and a discharging device. The input filter includes a capacitor to which an AC power source is provided. The discharging device rectifies and samples the AC power source. The discharging device generates a reference voltage according to a peak voltage of a generated sampling signal, generates an AC power source cutoff detection signal according to a comparison signal generated by comparing the sampling signal and a reference voltage, and discharges the capacitor through a discharging resistor according to the AC power source cutoff detection signal.

Abstract: An improved control circuit that is structured to energize another device such as a squib. A first portion of the circuit includes a first transistor and is structured to discharge at a first rate a first portion of a charge stored by a capacitor. Another portion of the circuit includes a second transistor and is structured to discharge a second portion of the charge subsequent to the discharge of the first portion of the charge and at a second rate greater than the first rate.

Abstract: A system for converting energy at a first voltage to a second voltage, including at least one source of voltage, a discharge switch, a variable capacitor, and a collection mechanism, connected in parallel, a charge switch between the discharge switch and the source, a transfer switch between the variable capacitor and the collection mechanism, and a controller to execute a control such that: a) during a first operation, the charge switch is closed to charge the variable capacitor, while the discharge switch and the transfer switch remain open; b) during a subsequent operation, the discharge switch is closed for a short instant while the charge switch remains open, allowing at least partial discharge of the variable capacitor.

Abstract: An energy harvesting circuit harvests energy from a voltage source and charges a storage element with the harvested energy. The energy harvesting circuit includes an energy source, a storage capacitor to store energy output from the energy source, a power converter circuit, an energy storage element, and an enabling circuit. The enabling circuit turns the boost converter circuit on and off according to a monitored capacitance voltage of the storage capacitor. When the boost converter circuit is turned off, the storage capacitor accumulates energy output from the energy source until a reference voltage is reached, whereupon the boost converter circuit is turned on, enabling current flow from the storage capacitor to the storage element. When the storage capacitor discharges to a minimum voltage level, the boost converter circuit is turned off. The enabling circuit and a reference voltage supply are powered by the energy source.

Abstract: The present invention provides wireless power supply systems that wirelessly supply power to a remote device for rapidly charging a charge storage capacitor, which charges a battery with the power stored in the charge storage capacitor. This allows the remote device to be positioned near the inductive power supply for rapid charging of the charge storage capacitor and allows battery charging to continue even after the remote device is removed from the inductive power supply.

Abstract: The invention concerns a power supply system for a field device connected to a wire-line network with a radio module configured for data communication with an external unit, wherein the radio module is connected to the field device and has a power supply unit. The power supply adapter is provided with a power transmitter for the wireless power transfer to the power supply unit. The power supply unit is configured with a power receiver, while the power receiver and the power transmitter are inductively coupled for the power transfer.

Abstract: A vehicle having an electricity accumulator for driving a vehicle, a charging inlet for receiving power supplied from a power supply provided on the outside of the vehicle, a circuit for charging the electricity accumulator with power from the power supply, and power lines for connecting the charging inlet and the charging circuit. An abnormality detector of vehicle having a circuit for applying a test voltage to the power lines, and an ECU as a short circuit detecting section. When the voltage value of the power line deviates from a predetermined normal range including the test voltage value although the test voltage is applied to the power line from the voltage application circuit, the ECU detects short circuit of the power line. The ECU specifies a short circuit mode corresponding to the detected short circuit among a plurality of short circuit modes based on the voltage value of the power line.

Abstract: An electronic device includes a primary power supply portion generating power by converting a first energy into electric energy as a second energy; a secondary power supply portion storing the electric energy obtained by the power generation; a charge detection portion detecting a state where the secondary power supply portion is not charged with the electric energy; a clocking portion clocking time and stopping display of clocked time when an operation input is detected; and a low power consumption state control portion which measures a time of a state where the operation input is detected and the charging is not performed, and stops the operation of the clocking portion when the measured time exceeds a preset time.

Abstract: A circuit includes a control circuit coupled to detect whether an electrical energy source is coupled to an input of a power converter. A switch is coupled to the control circuit to transfer energy from the input of the power converter to an output of the power converter during a first operating mode. The control circuit is coupled to drive the switch in the first operating mode when the electrical energy source is coupled to the input of the power converter. The control circuit is coupled to drive the switch in a second operating mode when the electrical energy source is uncoupled from the input of the power converter. The control circuit is coupled to discharge a capacitance coupled between input terminals of the power converter through the switch to a threshold voltage in less than a maximum period of time in the second operating mode.

Abstract: A method in a controller for energizing a chain-link converter including one or more phase legs, each phase leg including a number of series-connected converter cells, each converter cell including four valves arranged in an H-bridge connection with a DC capacitor. Each valve in turn includes a semiconductor switch in parallel with a diode. The method includes the steps of: charging the DC capacitor of each converter cell to a voltage level at which the semiconductor switches are controllable but below their nominal voltage; diagnosing the converter cells so as to detect failed components thereof; bypassing faulty components in a controlled manner; charging the DC capacitors to their nominal voltage. The invention also relates to a controller, computer programs and computer program products.

Abstract: The present invention discloses a charging system for charging a capacitor. The charge system includes at least one unit gain buffer, driven by a plurality of driving voltages, each unit gain buffer having a positive input terminal for receiving a target voltage and a negative input terminal coupled to an output terminal, a plurality of switches coupled between the plurality of driving voltages and the capacitor, and a switch control waveform generator, coupled to the plurality of switches, for switching on one of the for a specific driving voltage among the plurality of driving voltages to drive one of the at least one unit gain buffer to charge the capacitor.

Abstract: A discharge circuit for a DC power supply smoothing capacitor that is used in a power conversion device that supplies DC power via a switch to the DC power supply smoothing capacitor and an inverter, includes; a resistor that discharges charge in the capacitor; a switch connected in series with the resistor, that either passes or intercepts discharge current flowing from the capacitor to the resistor; a measurement circuit that measures a terminal voltage of the capacitor; and a control circuit that controls continuity and discontinuity of the switch; wherein the control circuit, after having made the switch continuous and starting discharge of the capacitor by the resistor, if a terminal voltage of the capacitor as measured by the measurement circuit exceeds a voltage decrease characteristic set in advance, makes the switch discontinuous and stops discharge by the resistor.

Abstract: An energy-scavenging interface includes first and second switches connected in series between an input and reference, and third and fourth switches connected in series between the input and an output. A control circuit closes the first and second switches and opens the third switch for a first time interval to store charge in a storage element. A scaled copy of a peak value of the charging current is obtained. The control circuit then opens the first switch and closes the third and fourth switches to generate an output signal as long as the value in current of the output signal is higher than the value of said scaled copy of the peak value.

Abstract: A set of electric motor drives for recapturing otherwise unused electrical energy from electric motors and methods of using same are disclosed that provide electrical energy in addition to mechanical energy by recapturing electrical energy that would be unused if conventional technologies were followed. Such recapturing motor drives can provide recaptured electrical energy to other loads, can transfer recaptured electrical energy to storage devices for future use, and/or can recirculate recaptured electrical energy back through a recapturing motor drive. By recapturing unused electrical energy, the recapturing motor drives generate significantly greater over-all energy output for any given electrical energy input drawn from any power source, thereby materially increasing the efficient and effective use of electrical energy drawn from the power source and dramatically reducing the relative consumption of electrical energy drawn from the power source.

Abstract: An electronic system has a capacitor that smoothes voltage of a direct current source, a resistance circuit that discharges charge of the capacitor, and an inverter circuit that converts the smoothed voltage into a three-phase ac voltage and applies this ac voltage to a motor. The resistance circuit has resistors and patterned wires disposed on a substrate such that the wires serially connect the resistors to discharge charge of the capacitor. The resistors are aligned in a straight line. The resistors located at positions different from ends of the series of resistors have resistance values lower than resistance values of the resistors located at respective ends of the series of resistors. More preferably, as the position of one resistor approaches the center of the series of resistors, the resistor is set at a lower the resistance value.

Abstract: A power conversion apparatus includes: a line breaker that is connected in series to a direct-current power supply; a first capacitor that is connected in parallel to the direct-current power supply through the line breaker; a discharge circuit that includes a resistor and a first switching circuit connected in series and is connected in parallel to the first capacitor; a power converter for driving a synchronous machine; a second capacitor that is connected in parallel to a direct-current side of the power converter; a second switching circuit that is connected in series between the first capacitor and the second capacitor; and a control circuit for controlling the discharge circuit. The control circuit controls the discharge circuit on the basis of the voltage of the first capacitor and the voltage of the second capacitor.

Abstract: There is provided a charge controller capable of charging a capacitor while suppressing the progress of deterioration of the capacitor without unnecessary charge/discharge of the capacitor. The charge controller includes a voltage sensor 133 that detects the voltage of a capacitor 101, a current sensor 135 that detects the charge/discharge current of the capacitor 101, a battery ECU 123 that estimates the SOC of the capacitor 101 based on the detected voltage, and a management ECU 117. The management ECU 117 calculates the charge/discharge amount from the start of charging of the capacitor 101 by integrating the charge/discharge currents detected by the current sensor 135 and controls the charging of the capacitor 101 based on the estimated SOC and the calculated charge/discharge amount. The management ECU 117 updates and sets the estimated SOC to an actual use upper limit SOC based on the state characteristics of the capacitor 101.

Abstract: A discharge circuit, an image forming apparatus having the discharge circuit, and a power-supply unit are disclosed to minimize a standby power generated in a standby mode and improve a discharging speed of a capacitor charged with electricity by the AC power in a power off mode. The discharge circuit connected between AC power input lines receiving an AC power includes a first resistor and a first switch element connected in series between the AC power lines, and a second resistor and a second switch element which are connected in series between the AC power lines, turn off the first switching element upon receiving an electric current during supply of the AC power, and turn on the first switching element in response to cutoff of the AC power to discharge the first capacitor.

Abstract: In the present invention, capacitor elements are connected in series and charged until the voltage between the terminals of a capacitor element whose capacitance is the lowest among the capacitor elements reaches a withstanding voltage. When the voltage between the terminals of the capacitor element reaches the withstanding voltage, the capacitor elements are connected in parallel, and the electric charge of the capacitor element is transferred to the other capacitor elements.

Abstract: A power-source apparatus for a vehicle comprises a generator driven by an engine and generating power, a power-storage device storing the power generated by the generator thereat and supplying the power stored thereat to an electric load, and a control device configured to detect a deterioration state of the power-storage device and change a voltage of the power-storage device during a soak in accordance with the deterioration state of the power-storage device detected. Thereby, the improvement of the fuel economy can be achieved and also the necessary durability of the power-storage device can be ensured.

Abstract: A circuit can be used for charging a capacitor with an AC voltage. In one embodiment, the circuit includes a capacitor coupled to be charged with the AC voltage. An adjustment is configured to adjust a capacitor charge speed according to a value of the AC voltage. The adjustment circuit includes at least one bipolar transistor coupled to receive a voltage at a base of the bipolar transistor. The voltage is a function of the value of the AC voltage.

Abstract: An ingestible apparatus produces and processes physiological signals representative of a physiological parameter. The apparatus measures the physiological parameter from within the body of a living entity. The apparatus includes a physiological transducer circuit to sense the physiological signals, a processor to process the physiological signals in response to the physiological transducer circuit, and a transmitter that transmits the processed signals during transmission intervals which are alternated with idle intervals. The apparatus further includes a capacitor-based circuit, including at least one capacitor, to accumulate sufficient charge during one of the idle intervals to supply power to the transmitter during one of the transmission intervals.

Abstract: Embodiments of the present invention relate to an apparatus and method for collecting and/or storing electrical energy in lightning. A specific embodiment provides a lightning energy storage system that includes a lightning rod, a wire, a lightning energy harvester, and a ground rod. The lightning rod is configured to attract lightning and transfer electrical energy. The lightning energy harvester incorporates at least one magnetic capacitor and a switch. The ground rod is connected to the wire. A control signal controls the switch to direct the electrical energy to ground through the ground rod or to direct the electrical energy to charge the magnetic capacitor, in response to a charging state of the magnetic capacitor.

Abstract: A voltage multiplying circuit comprising: a first capacitor, comprising a first terminal and a second terminal, wherein the first terminal of the first capacitor is selectively coupled to a first voltage or a second voltage, and the second terminal is selectively coupled to the first voltage or a fourth voltage; a second capacitor, comprising a first terminal and a second terminal, wherein the first terminal of the second capacitor is selectively coupled to the second voltage or the fourth voltage, and the second terminal of the second capacitor is selectively coupled to a third voltage or the fourth voltage; and a third capacitor, comprising a first terminal and a second terminal, wherein the first terminal of the third capacitor is selectively coupled to the second voltage or the fourth voltage, and the second terminal of the third capacitor is selectively coupled to a third voltage or the fourth voltage.

Abstract: An electronic circuit comprising a circuit module, a capacitor connected to the circuit module and a shutdown line providing a shutdown signal to the circuit module for suspending the circuit module. The electronic circuit further comprises a switching module for switching the capacitor such as to reduce discharging of the capacitor, depending on the shutdown signal. Particularly, the switching module disconnects the capacitor from ground. Disconnection takes effect when the circuit module is suspended or in power down mode because of the shutdown signal being provided.

Abstract: An integrated circuit (IC) having an internal power supply voltage step down circuit provides efficiency while requiring a minimum of external terminals. In a first operating mode, a storage capacitor is charged from the power supply return of a group of circuits, while the group of circuits is powered from an input power supply voltage provided to the IC. In a second operating mode, the group of circuits is powered from the storage capacitor. The step-down circuit provides for halving the input power supply voltage, but multiple storage capacitors and additional operating modes can be provided for voltage division by greater factors. A sensing circuit can be employed to sense the voltage across the storage capacitor(s) and in response, select the operating mode, providing hysteretic control of the voltage supplied to the group of circuits.

Abstract: A method for manufacturing and operating a semiconductor device is disclosed. The semiconductor device includes a first capacitor node, a second capacitor node, a first capacitor electrode, a second capacitor electrode, a first switch and a second switch. The first switch is coupled between the first capacitor electrode and the first and second capacitor nodes such that the first switch has a first position that couples the first capacitor electrode to the first capacitor node and a second position that couples the first capacitor electrode to the second capacitor node. The second switch is coupled between the second capacitor electrode and the first and second capacitor nodes such that the second switch has a first position that couples the second capacitor electrode to the first capacitor node and a second position that couples the second capacitor electrode to the second capacitor node.

Abstract: A battery system comprises at least one battery cell and a high-voltage network connected thereto which includes a pre-charge circuit having at least one pre-charge resistor. The battery system further comprises a component including a link capacitor with a specific capacitance. A method for controlling the battery system includes measuring a first voltage at the link capacitor before charging, charging the link capacitor, and measuring a second voltage at the link capacitor after charging. The method further includes forming a voltage difference from the first and the second voltage, and determining an energy received by the pre-charge resistor based on the voltage difference at the link capacitor and based on the capacitance of the link capacitor.

Abstract: The present invention provides wireless power supply systems that wirelessly supply power to a remote device for rapidly charging a charge storage capacitor, which charges a battery with the power stored in the charge storage capacitor. This allows the remote device to be positioned near the inductive power supply for rapid charging of the charge storage capacitor and allows battery charging to continue even after the remote device is removed from the inductive power supply.

Abstract: A device includes a backup power supply configured to provide power to an external system upon loss of primary system power, the backup power provided by at least one capacitor; logic to create, while the capacitor is available as the backup power supply to the external system, a transient elevation of the capacitor's stored potential above a upper predetermined operating potential of the capacitor; logic to obtain measurements of the capacitor's output voltage during the transient elevation of the capacitor's stored potential; and logic to determine a capacitance of the capacitor from the measurements; the device comprising multiple capacitors in series; logic to discharge each capacitor in series individually from the others; and logic to monitor for overcharging of any of the capacitors in series, and, during charging of the capacitors in series, to operate the discharge logic for any capacitor in the series that is in danger of overcharging.

Abstract: A method and system are disclosed for controlling electrical current through an inductive load. The electrical current is supplied by one of at least three selectable dual capacitor bank electrical circuits. The method includes storing electrical energy during a charge operating state in first and second capacitor banks of a first dual capacitor bank circuit. The stored electrical energy is then used to drive the inductive load when operating the first dual capacitor bank circuit in a drive operating state. After depleting the stored electrical energy from the first and second capacitor banks, the first dual capacitor bank transitions to a collection operating state that includes collecting electrical energy from the inductive load. A second and third dual capacitor circuits simultaneously transition among the charge operating state, the drive operating state, and the collection operating state during operation.

Abstract: An apparatus comprising a capacitor circuit, a control circuit, and a resistor circuit. The capacitor circuit may be configured to (i) be charged through an input terminal and (ii) store a charge sufficient to run a device on an output terminal. The control circuit may be configured to (i) charge the capacitor through the input terminal, (ii) couple the input terminal to a voltage source, and (iii) discharge the capacitor circuit when the output terminal is not connected to the device drive.

Abstract: There is provided a capacitance sensing apparatus including: a driving circuit unit applying a driving signal to a first capacitor; a first integrating circuit unit including a second capacitor charged by a change in capacitance generated in the first capacitor based on the driving signal to generate a first output voltage; and a second integrating circuit unit including a third capacitor charged by a change in capacitance generated in the second capacitor to generate a second output voltage, wherein a level of the second output voltage is changed at least twice during a single period of the driving signal applied to the first capacitor.

Abstract: Shuttering eyewear (or shutter glasses) may be used to enable stereoscopic 3D and to provide different images to two viewers using a single display, known as Dual View. The shuttering eyewear may utilize charge recovery circuits. The charge recovery circuits may achieve high charge recovery efficiencies on the order of 80 to 90 percent resulting in a dramatic reduction in power supply battery operating current and a resulting increase in operating time. The charge recovery circuits may utilize switch mode boost conversion to recover most of the charge from a shutter that is being closed to one that is to be opened. Further, a charge recovery method for utilizing energy stored on a capacitive storage device may include closing a first active shutter, moving charge to a converter in buck mode to a capacitor, and pulling charge from the capacitor to open a second shutter.

Abstract: A switch is coupled to a control circuit and to an input of a power converter. The control circuit is coupled to drive the switch in a first operating mode to transfer energy from the input to an output of the power converter when an electrical energy source is coupled to the input of the power converter. The control circuit is coupled to drive the switch in a second operating mode when the electrical energy source is uncoupled from the input. A capacitance is coupled between input terminals of the input of the power converter and is discharged to a threshold voltage in less than a maximum period of time from when the electrical energy source is uncoupled from the input terminals. The control circuit is coupled to drive the switch to have a high average impedance in the first operating mode.

Abstract: A power conversion system may include a controller to cause a power stage to control the flow of power to or from an energy storage device in response to a dynamic reference. The flow of power to or from the energy storage device may be controlled at a substantially higher speed than power fluctuations in a power source or load. In a power conversion system, a model including an energy storage device may be generated in real-time, and a condition of the energy storage device may be determined in response to the model.

Abstract: A capacitance detector includes: a first capacitor with fixed base capacitance and variable capacitance; a second capacitor charged with base charge corresponding to the base capacitance; third and fourth capacitors which receive capacitance distribution from the first or second capacitor; a first switching means for charging the first and second capacitors to a first fixed voltage and charging the third and fourth capacitors to a second fixed voltage in a first section and for charging the first and second capacitors to the second fixed voltage and charging the third and fourth capacitors to the first fixed voltage in a second section; a second switching means for separating the first and second capacitors from the third and fourth capacitors and for connecting the first and second capacitors to the third and fourth capacitors; and a differential amplifier to which first and second voltages corresponding to equalized charge are differentially input.

Abstract: A power source generation circuit includes a regulator circuit which receives an external power source voltage VDDA from an external power source, and generates a predetermined internal power source voltage on a given terminal VDD; and a charging circuit which connects the external power source and the given terminal when the external power source voltage VDDA supplied from the external power source is equal to or lower than a predetermined threshold voltage.

Abstract: A control circuit is provided which includes a pre-charge circuit connected in parallel with a solid state switching device of, for example, a power distribution network. The pre-charge circuit pre-charges a load capacitance at a load side of the switching device prior to activation of the switching device. The pre-charge circuit includes a threshold waveform generation circuit and an over-current detect circuit. The threshold waveform generation circuit synthesizes a maximum acceptable charging waveform for the pre-charge circuit in charging the load capacitance, and the over-current detect circuit signals an over-current fault condition upon a charging current through the pre-charge circuit exceeding the synthesized, maximum acceptable charging waveform. The pre-charge circuit includes a sense resistor coupled to a power input side of the solid state switching device, with charging current through the pre-charge circuit being monitored via the sense resistor.

Abstract: Systems, apparatus, and methods are provided for initializing a voltage bus. An exemplary system includes an input interface, a voltage bus, discharge circuitry coupled to the voltage bus, connection circuitry coupled between the voltage bus and the input interface, and a control module coupled to the connection circuitry and the discharge circuitry. The control module activates the discharge circuitry prior to activating the connection circuitry.

Abstract: A bleeding circuit and method for an electromagnetic interference filter detect whether or not an AC power source connected to the electromagnetic interference filter is removed, establish a discharge path for discharging a capacitor of the electromagnetic interference filter once the connected AC power source is removed, and cut off the discharge path during the AC power source is in connection to the electromagnetic interference filter for decreasing power consumption of the electromagnetic interference filter.

Abstract: In an electric vehicle inverter apparatus 100, a vehicle control controller 15 detects a switch open signal output from a collision detector 16 when the collision detector 16 is caused by a collision between electric vehicles to operate. Then, an inverter main circuit connection switch 10 of a high-voltage battery unit 8 is put into an open state. Thus, the direct-current power supply from a high-voltage battery 12 to a DC bus portion is interrupted. In addition, electric charges charged into a main circuit capacitor 7 are discharged by a forced discharge circuit portion 22b.

Abstract: A method includes forming a power control circuit through coupling a gate switch array between a buffer stage at an input of the power control circuit and an amplifier array including N amplifier stages in parallel to each other, with N>1. The method also includes coupling each of the N amplifier stages to a corresponding gate switch of the gate switch array, and controlling an output power of the power control circuit by switching one or more appropriate gate switches of the gate switch array to apply an input signal from the buffer stage to a corresponding one or more amplifier stages coupled to the one or more appropriate gate switches such that a maximum output power is achieved when all of the N amplifier stages are turned on and a minimum output power is achieved when only one amplifier stage is turned on.

Abstract: Provided is a power supply device for an image forming apparatus, the power supply device including: a filter unit filtering alternating current (AC) power from an AC power source; and a converter generating a direct current (DC) power from the filtered AC power, wherein the filter unit includes: a capacitor connected to the AC power source; a discharge device connected to the capacitor and discharging electric charges accumulated in the capacitor; and a switching device switching connection between the capacitor and the discharge device according to a power supply mode of the power supply device.

Abstract: The present invention relates to an electrical device for charging accumulator means (5), said electrical device comprising: a motor (6) connected to an external mains (11); an inverter (2) connected to the phases of said motor (6); and switching means (4) integrated into the inverter (2), said switching means (4) being configured to permit said motor (6) to be supplied and to permit the accumulator means (5) to be charged by the inverter (2). According to the invention, said electrical device further includes, for each phase of said motor (6), an RLC low-pass filter (18) connected, on the one hand, to the mid-point (16) of the phase of said motor (6) and, on the other hand, to ground.

Abstract: A system for providing backup power supply to a device is provided. The system includes a supercapacitor and a single circuit for charging and discharging of a supercapacitor. The single circuit operates with an inductor to provide for charging and discharging of the supercapacitor.

Abstract: A circuit for charging a capacitor block including series-connected capacitive elements has an input node for receiving an input, an output node coupled to the capacitor block, a third capacitive element connectable to the input node and the output node, and first and second switching circuitries coupled to the third capacitive element. A voltage sensor determines a relationship between first voltage at the first capacitive element and second voltage at the second capacitive element to separately control switching of the first and second switching circuitries in accordance with the relationship between the voltages.

Abstract: A method for charging an intermediate circuit capacitor in a precharging unit includes charging the intermediate circuit capacitor via a current source and adjusting the supplied current in such a manner that a constant power loss is produced in the current source during the entire charging operation. A circuit arrangement includes a battery which is connected to a current source which is connected to an intermediate circuit capacitor via a switch. An adjusting circuit is arranged in parallel with the current source and can be used to adjust the current for charging the intermediate circuit capacitor. The current is adjusted in such a manner that a constant power loss is produced in the current source during the entire charging operation.

Abstract: A high voltage dc power source for providing a charging current to an electronic device, including one or more strings connected in parallel, each string being subdivided into dc power source units connected in series and each string being provided with a solid-state switch configured to connect and disconnect the string, and a control unit adapted to turn on and turn off the solid-state switch, and the control unit is configured, upon receiving an order to connect the string, to control the switch of the string to be alternately turned on and off so that a soft charging of the electronic device is achieved.