Abstract: Automatic transient control circuitry may be used to alleviate issues relating to large changes in power demands by a load in an integrated circuit. The transient control circuitry may inject current to or retract current from a load, for example charging or discharging a bypass capacitor associated with the load, when circuitry of the load is commanded to an operational state from a standby state or vice-versa, respectively.

Abstract: A system, method, and apparatus is disclosed for interfacing and transferring power unidirectionally or bidirectionally between a direct current (DC) line and a single or multiphase alternating-current (AC) line for only half of any given phase and only a single phase at a time when polarity is matched between the DC and the AC system. A circuit with simplified, robust, and reduced-cost components perform the power conditioning and the synchronization as a system that simulates a half-wave rectifier/inverter.

Abstract: A receiver includes a first stage buffer, a second stage buffer and a third stage buffer. The first stage buffer includes an input portion electrically coupled to a first voltage node, and configured to change a voltage level of an output node in response to an input signal, first and second load portions electrically coupled between a second voltage node and the output node, and electrically coupled to each other and a duty cycle adjustment portion electrically coupled between the first and second load portions, and configured to provide a correction current to the output node through the first load portion.

Abstract: The invention relates to a redundant module for decoupling short-circuit currents in a redundant voltage supply. The redundant module comprises at least two power supply units, and the number of inputs corresponds at least to the number of power supply units. Each input is routed via a separate current path to a common current node of an output for providing an output current. Each current path forms a decoupling section, and at least one measuring element for measuring the input voltage, the input current, and/or the input power as well as a control element for regulation purposes are assigned to each decoupling section.

Abstract: A method for powering up a circuit comprising a plurality of sections of progressively increasing size is described. The method comprises receiving a signal for powering up the circuit, and, in response to the signal, sequentially powering up the plurality of sections in an order of increasing size.

Abstract: Each of the power supply units in a power supply apparatus includes a voltage conversion circuit that converts input voltage into output voltage within a predetermined voltage range an output capacitor that outputs supply power while accumulating charges according to the voltage converted by the voltage conversion circuit, and an overload detection circuit that detects an overload of the output capacitor and when the overload is detected, notifies an apparatus operated using the power supplied from the power supply apparatus of an overload signal requesting a suppression of power consumption.

Abstract: Predictive phase balancing is implemented by a host system computer and logic executable by the host system computer. The logic is configured to receive customer demand profiles from each customer serviced by a poly-phase grid network and create a demand forecast from anticipated power demands collected from the customer demand profiles. Creating the customer demand profiles includes breaking down loads for each customer by corresponding phases in the poly-phase power grid network. The loads correspond to the anticipated power demands. The logic is also configured to balance the loads among each of the phases based on any load imbalances determined from the demand forecast.

Abstract: Predictive phase balancing is implemented by receiving customer demand profiles from each customer serviced by a poly-phase grid network and creating a demand forecast from anticipated power demands collected from the customer demand profiles. Creating the customer demand profiles includes breaking down loads for each customer by corresponding phases in the poly-phase power grid network. The loads correspond to the anticipated power demands. The predictive phase balancing is further implemented by balancing the loads among each of the phases based on any load imbalances determined from the demand forecast.

Abstract: A low-power protective circuit includes a detection unit that intermittently detects a voltage across a secondary battery; a battery management unit that includes a buffer memory device and a processor and determines, based on a value of the voltage, whether the secondary battery needs to be charged; a switch circuit that establishes or breaks electrical continuity between a host system and the secondary battery; a switch control unit that turns on or off the switch circuit in accordance with the judgment made by the battery management unit; a switch that controls supply of power supply voltage from the secondary battery to the battery management unit; and a power controller that intermittently stops supply of the power supply voltage to the battery management unit by turning off the switch.

Abstract: A power supply unit includes a plurality of the interface ports and a plurality of power delivery units, each coupled to one of the interface ports and configured to extract power from data signals communicated over the interface ports by remote devices. A sharing circuit is coupled to each of the power delivery units for generating a power supply voltage from the power extracted from the data signals. A controller is configured to generate a communication line power loss estimate for each of the interface ports and configure the power delivery units to balance amounts of power supplied by each of the remote devices based on the communication line power loss estimates.

Abstract: An electric vehicle includes a controlling device and a battery unit. The controlling device is connected to a switch, an electric motor, an accelerator controller, and a generator unit. The switch is connected to the generator unit. The battery unit includes a primary battery and a secondary battery. The primary battery is connected to the controlling device. The secondary battery is connected to the generator unit. When the switch is turned on, the controlling device and the generator unit are activated, and when the accelerator controller activates the generator unit via the generator unit controlling device, the controlling device firstly supplies power to the electric motor by the generator unit. After the electric motor has been started, the controlling device cuts off power supply from the generator unit to the electric motor, and the primary battery supplies power to the electric motor.

Abstract: A timing control circuit for an electronic device is disclosed. The timing control circuit includes a first power supply voltage input, a second power supply voltage input, a third power supply voltage input, a first output, a second output, a switch circuit and a control circuit. The control circuit is connected with the switch circuit and configured to turn the switch circuit on/off. The switch circuit is connected between the first power supply voltage input and the first output and responds to the control circuit to delay, by means of adjustable (different capacitance values) capacitors, the power connections when the electronic device is turned on but to immediately disconnect the power connections when the electronic device is shut down, thereby controlling the sequence of power applications and avoiding the need for expensive chips or circuits.

Abstract: A fail-safe static switch for controlling the supply of redundant electrical power to critical loads. A first control path has a signal analyzer configured to monitor predetermined characteristics of a power supply voltage. The signal analyzer generates a first failure signal when the characteristics of the power supply voltage monitored by the signal analyzer are not in compliance with predetermined metrics. A second control path has a first electrical circuit configured to monitor predetermined characteristics of the power supply voltage. The first electrical circuit generates a second failure signal when the characteristics of the power supply voltage monitored by the first electrical circuit are not in compliance with predetermined metrics. The fail-safe static switch further includes an output providing an electrical output signal. The electrical output signal changes state when at least one of the first failure signal and the second failure signal are generated.

Abstract: System for providing AC line balancing includes a three-phase power source, a monitoring component and a control component. Three AC lines from the three-phase power source are coupled to a first set of loads and a set of transfer switches. Additionally, the set of transfer switches are configured to be coupled to a second set of loads. The monitoring component is configured to detect current provided by the three AC lines to identify the AC lines providing the highest and the lowest levels of currents to the first and second sets of loads. The control component is configured to configure at least one transfer switch in the set of transfer switches to decouple the AC line providing the highest level of current to a load of the second set of loads and couple the AC line providing the lowest level of current to that load.

Abstract: A method for the control of a first current in a first direct voltage network which is connected to a direct voltage converter, wherein energy is transmitted between the first and a second direct voltage network via a transformation unit of the direct voltage converter, wherein a current control is provided for the control of a second current in the second direct voltage network. A second current setpoint is determined from a first current setpoint of the first direct voltage network based on a transfer function of the transformation unit, which second current setpoint is fed to the current control and therefore, due to the transformation ratio of the transformation unit, a first actual current of the current-control-free direct voltage network is controlled.

Abstract: An inverter communication system is provided. The system includes a plurality of inverters connected to each other through a communication line, and assigned with different original identifiers for mutual distinction, wherein each of the plurality of inverters: receives a data frame transmitted through a previous inverter; selectively transmits the received data frame to a subsequent inverter; generates a data frame to be transmitted when data to be transmitted to a specific inverter occur; and transmits the generated data frame to a subsequent inverter.

Abstract: A device is provided for use with an audiovisual device and an HDMI cable having a first end and a second end. The first end can connect to the audiovisual device, whereas the second end can connect to the device. The audiovisual device can provide power to the power line of the HDMI cable when providing the digital television audiovisual signals. The device includes an output portion, and input portion and a control portion. The output portion can provide output signals as the digital television audiovisual signals to the second end. The input portion can receive input signals as the digital television audiovisual signals from the second end. The control portion can instruct the output portion to output the digital television audiovisual signals to the second end or can instruct input portion to receive the digital television audiovisual signals from the second end based on the power.

Abstract: A method for converting electrical power includes providing a modular power converter having a mode control module and a plurality of autonomously operating power conversion modules operatively connected to a first power bus; selecting, by the mode control module, individual modes of operation for the plurality of power conversion modules to meet a power conversion requirement; receiving electrical power of a first power type from the first power bus by at least one of the power conversion modules; and converting the received electrical power into electrical power of a second power type by the at least one power conversion module.

Abstract: A power sharing device and method thereof are disclosed herein. The power sharing device includes a control unit, multiple regulators and multiple feedback circuits. Each regulator includes a first input terminal, a second input terminal and an output terminal. The control unit generates multiple pulse-width modulation signals. The first input terminal receives one of multiple input voltages. The second input terminal receives one of the pulse width modulation signals. The output terminal selectively outputs an output power. Each feedback circuit is coupled between the second input terminal and the output terminal of one of the regulators. The output terminals of the regulators are coupled to a load, and the regulators selectively output the output power one at a time and in rotation according to the input voltages and duty cycles of the pulse-width modulation signals.

Abstract: A plurality of modules each including at least a pair of series connected power MOSFETs are configured between a plurality of DC voltage sources, and a plurality output terminals for connection to respective loads, are controlled for selectively applying power to the loads via time delay switching incorporating forward biased intrinsic diodes of the MOSFETs in a given current path during initial application of power to a load, whereby a predetermined period of time after turning on one of the series connected MOSFETs, the associated other MOSFET is turned on to shunt its intrinsic diode for reducing the resistance in the current path to maximize current flow. The configuration of the plurality of power MOSFETs is also controlled for selectively providing bi-directional current flow between said plurality of DC voltage sources.

Abstract: A power management unit, adapted to a wireless power supplying unit, for switching between input powers and providing a rated voltage or a variable flow current is provided. The power management unit includes a rectifying unit, a regulating unit, and a control unit. The rectifying unit converts AC power into DC power. The regulating unit is connected to the rectifying unit and generates a stable rated voltage or a variable flow current. The control unit is connected to the regulating unit and controls the input power driving the regulating unit. In addition, an apparatus and a method for a wireless power supplying unit are provided.

Abstract: The present disclosure provides a solar cell pack and a method for balancing currents of solar cell modules. The solar cell pack includes a first solar cell module, a second solar cell module, a first balancer, a sampler and a controller. A negative pole of the first solar cell module is electrically connected to a positive pole of the second solar cell module. The first balancer is electrically connected to the first and the second solar cell modules in order to balance the current flowing through the both solar cell modules. An input terminal of the sampler is electrically connected to the first and the second solar cell modules. An output terminal of the sampler is electrically connected to an input terminal of the control unit. An output terminal of the control unit is electrically connected to an input terminal of the first balancer.

Abstract: The present invention relates to a method and a circuit for power switching. The method comprises the steps of: providing a operation circuit; receiving a command from a Host and setting up a power mode of the operation circuit; supplying a first rated consuming power source and then a second rated consuming power source to the operation circuit via the power switching circuit according to power mode; detecting the transferring process form the first rated consuming power source to second rated consuming power source; and preventing over current according to detecting result.

Abstract: The present invention provides a power integrated device including a detection circuit and a determination circuit. The detection circuit detects whether first and second connection ports are coupled to a power source and produce first and second valid signals, respectively, and detect whether the power source coupled to the first and second connection ports meet first or second predetermined power values and produce first and second power spec signals, respectively. The determination circuit produces a system power-control signal according to the first valid signal, the second valid signal, the first power spec signal and the second power spec signal to turn on or turn off the power integrated device.

Abstract: A technique for combining power to a single load from multiple power supplies using power over Ethernet (PoE) is disclosed. Each power supply is coupled to associated power sourcing equipment (PSE) providing PoE, and each PSE has a current limit. The power supplies supply approximately the same voltage, but the output voltages are typically not exactly equal. All the power supplies are connected via diodes to a common load terminal. The power supply outputting the highest voltage first supplies power to the load terminal, since only its diode is forward biased, until a PoE current limit is reached. Then its duty cycle is limited. The load terminal voltage is then inherently lowered to cause the diode of the power supply with the next highest output voltage to connect it to the load to supply additional power to the load as the first power supply continues to supply its limited current.

Abstract: A voltage reference circuit is provided that includes a first circuit, a second circuit and a third circuit. The first circuit has a first MOS transistor pair and the second circuit has a second MOS transistor pair. The first circuit is configured to provide a first voltage component that changes at a first rate having a first slope as a temperature to which the voltage reference circuit is subjected changes. The second circuit is configured to provide a second voltage component that changes at a second rate having a second slope as the temperature changes. The third circuit is configured to use the first voltage component and the second voltage component to generate the reference voltage component that changes at a fifth rate having a fifth slope as the temperature changes. The fifth slope is substantially equal to zero to promote insensitivity of the reference voltage component to temperature changes.

Abstract: Disclosed is a low drop-out voltage regulator circuit with a distributed output network coupled to a pixel array for use in image sensor circuitry. The regulator circuit comprises voltage regulating circuitry and a distributed output network, wherein the distributed output network comprises drive transistors disposed along and connected between a supply track and an output track. The spatial distribution of the drive transistors improves heat dissipation within the regulator circuit, and a combination of low current flow and regulated output voltage reduces IR drop across the output track. The improved heat dissipation increases device lifespan and performance, whereas the reduction in IR drop across the output track provides better pixel response, readout uniformity, and image quality.

Abstract: Techniques for reducing cross-supply current are described herein. In one embodiment, a power circuit comprises a bypass switch coupled between a first power supply and an internal power supply, and a voltage regulator coupled between a second power supply and the internal power supply. The power circuit also comprises a shut-off circuit configured to detect the first power supply powering up before the second power supply during a power-up sequence, to shut off the bypass switch upon detecting the first power supply powering up before the second power supply, to detect the second power supply powering up during the power-up sequence, and to release control of the bypass switch to a controller upon detecting the second power supply powering up.

Abstract: Methods, systems, controller devices, and computer program products for reactive power control at a renewable energy site are provided. Embodiments address dynamic performance problems associated with control loop delay and the changing modes of operation for meeting utility voltage and reactive power constraints. Provided is a method for reactive power control involving: (a) determining a site-wide reactive power command comprised by a sum of a reactive power feedforward or compensation term and an integrator term; and (b) distributing the site-wide reactive power command among inverters.

Abstract: A resonant transformer connected between a ground terminal and elevated terminal draws current from the earth's electric field through a primary winding of the transformer. An impulse generator applies a high voltage impulse to the primary winding of the resonant transformer to cause current to flow from the ground terminal through the primary winding. The flow of current through the primary winding of the resonant transformer induces a current in the secondary winding, which may be converted and filtered to a usable form, e.g. 60 Hz AC or DC.

Abstract: The system and apparatus of one or more embodiments of the present invention extracts, conditions, and conveys electric power from the earth ionosphere cavity through the integrated and collaborative operation of the system and apparatus consisting of a capacitively-coupled insulated elevated terminal (coupled capacitor upper plate), an evacuated spark gap, an integrated step-down transformer and resonant capacitor, and a ground terminal (coupled capacitor lower plate). The architecture governing exemplary embodiments of the system and apparatus of the present invention emulates the natural architecture governing the interaction of living trees with the electrical energy resident in the earth ionosphere cavity. The implementation of such exemplary embodiments of the present invention utilizes standard and customized components appropriate for their function within the system and apparatus.

Abstract: An internal power circuit lowers a battery voltage supplied always from an external side to generate a standby power voltage. A timer continues to measure an elapse of time in a standby state, after a main relay is turned off and supply of a power voltage is interrupted. A measured time data of the timer is saved to a save register during a time measurement operation of the timer. When a stop condition for stopping the time measurement operation of the timer is satisfied, a control circuit stops the operation of the internal power circuit. When the main relay is turned on, the internal power circuit is activated to start its operation again by the control circuit so that the measured time data saved to the save register is restored to the timer.

Abstract: Disclosed is a current and voltage detection circuit comprising: a voltage input terminal to which a direct current voltage is applied; a voltage comparison circuit that determines which of the applied voltage and a predetermined voltage is larger; a switching element connected in series to a current-voltage conversion unit, between a positive electrode terminal of the power supply and a reference potential point of the circuit; and a control circuit that generates a control signal of the switching element in response to output of the voltage comparison circuit, wherein the circuit turns ON the switching element and determines the voltage, by the voltage comparison circuit, when a voltage supply capability or current supply capability is low; and turns OFF the switching element by the control signal and determines the voltage, when the voltage comparison circuit determines that the voltage is higher than the predetermined voltage.

Abstract: A plurality of modules each including at least a pair of series connected power MOSFETs are configured between a plurality of DC voltage sources, and a plurality output terminals for connection to respective loads, are controlled for selectively applying power to the loads via time delay switching incorporating forward biased intrinsic diodes of the MOSFETs in a given current path during initial application of power to a load, whereby a predetermined period of time after turning on one of the series connected MOSFETs, the associated other MOSFET is turned on to shunt its intrinsic diode for reducing the resistance in the current path to maximize current flow. The configuration of the plurality of power MOSFETs is also controlled for selectively providing bi-directional current flow between said plurality of DC voltage sources.

Abstract: A power supply circuit according to an embodiment of the invention includes: voltage sources; voltage control circuits that boost an input voltage; and a voltage source connection switch that connects at least one of the voltage sources to one of the voltage control circuits. For example, the voltage source connection switch connects, to the voltage control circuit, a voltage source having a voltage lower than a predetermined reference voltage among the voltage sources, and connects, to the voltage control circuit, a voltage source having a voltage equal to or higher than the determined reference voltage among the voltage sources.

Abstract: A converter circuit arrangement is provided, including a converter switch controller, a converter switch, a load circuit interface and an inductor. The converter switch controller may include a control input. The converter switch may be coupled between a first power supply potential and the control input. The inductor may be coupled between a second power supply potential and the load circuit interface. The load circuit interface may be coupled between the control input and the inductor.

Abstract: An electronic device comprising a first power switch connectable or connected between a first voltage source and a load is proposed. The first power switch assumes a conductive state in response to a power-on request and a non-conductive state in response to a power-off request, for energizing and deenergizing the load, so that a voltage across the first power switch tends to a positive high level when the first power switch is in the non-conductive state and to a positive low level when the first power switch is in the conductive state. The device further comprises a second power switch connectable or connected between a second voltage source and the load. The second power switch assumes a conductive state in response to the power-on request and a non-conductive state when the voltage across the first power switch is below a defined switch-off threshold lower than the high level. The second voltage source thus assists the first voltage source in powering up the load.

Abstract: In operating an inverter including input connectors, (i) to which strings of photovoltaic cells are connected, (ii) each of which is connected via a DC/DC converter to a common DC voltage link, and (iii) which are bridgeable, the partial powers flowing through the individual DC/DC converters are determined, and for some time at least two DC/DC converters are either operated with the aim of balancing the partial currents flowing through them or connected through. During this operation or connecting through, the partial powers flowing through the at least two DC/DC converters are compared with each other, and if a difference between the partial powers exceeds a threshold value, the DC/DC converters are subsequently operated in a way adjusted to the fact that they connect different strings to the DC voltage link.

Abstract: A multi-mode current-allocating device serves to control the DC to DC converter in each power supply device of a distributive power supply system. The multi-mode current-allocating device has an active current-sharing control circuit, a current-allocating bypass circuit, and a droop current sharing control circuit to be selectively operated under an active current-sharing mode, a current-allocating mode or a droop current-sharing mode according to the factors of the type of input power of each power supply device, the state of system load, and the system reliability so as to maintain the power supply efficiency of entire power supply system and reduce unnecessary power loss.

Abstract: A method controls power generated by a photovoltaic array. The method estimates a voltage corresponding to a global maximum power point (MPP) of the power generated by the photovoltaic array to produce an estimated voltage; and tracks an output of the power based on the estimated voltage to determine the global MPP.

Abstract: In a variable voltage circuit 50, a resistive element 104 and a magnetoresistance effect element 108 are connected in series between a first voltage source 101 and a second voltage source 102. A magnetic field supply mechanism 121 that applies a magnetic field to the magnetoresistance effect element 108 is provided in the vicinity of the magnetoresistance effect element 108. The magnetic field supply mechanism 121 can vary the resistance value of the magnetoresistance effect element 108 by varying the magnetic field. A node 106 between the resistive element 104 and the magnetoresistance effect element 108 is connected to an output terminal 103.

Abstract: A first output voltage of a constant-voltage power supply is applied as a reference voltage of a multi-channel A-to-D converter and a monitor signal obtained by smoothing the first output voltage by a first power-supply filter is inputted as an input signal voltage. A micro-processor periodically writes digital conversion data of the monitor signal into shift registers to calculate a maximum deviation using a maximum value and a minimum value of the latest predetermined number of data, and determines a power-supply abnormality when the maximum deviation exceeds a predetermined threshold value.

Abstract: An uninterruptible power supply (UPS) system (100) comprises a plurality of UPS units (UPS-1, UPS-2) connected in parallel. The controllers (130) of the units are programmed to implement a voltage calibration procedure and a current calibration procedure, in order that measurements of voltage and current made by sensors within the different units will agree. In the current calibration procedure, the load is disconnected (302) while one of the units is selected as a master and operates in a voltage control mode (VCM) (Steps 304-308). Each other unit is selected in turn and operated in a current control mode (310, 312). Current measurements made in the master unit are communicated (314) via a data bus to the selected unit and compared (316) with measurements made in the unit itself. The unit adapts its current sensing gains to match the master unit.

Abstract: Methods and systems for power management include determining a voltage level of a grid; if the voltage level is below a lower voltage threshold, setting power outputs for one or more distributed generators on the grid to maximum; and if the voltage level is above the lower voltage threshold and below an upper voltage threshold, determining power outputs for one or more distributed generators on the grid using sensitivity-based distributed Q compensation.

Abstract: A distributed power harvesting system including multiple direct current (DC) power sources with respective DC outputs adapted for interconnection into a interconnected DC power source output. A converter includes input terminals adapted for coupling to the interconnected DC power source output. A circuit loop sets the voltage and current at the input terminals of the converter according to predetermined criteria. A power conversion portion converts the power received at the input terminals to an output power at the output terminals. A power supplier is coupled to the output terminals. The power supplier includes a control part for maintaining the input to the power supplier at a predetermined value. The control part maintains the input voltage and/or input current to the power supplier at a predetermined value.

Abstract: Load sharing apparatus for load sharing between a plurality of power supplies (1, 2). The apparatus comprises one or more load sharing modules (Share1, Share2), each for association with a respective power supply. The or each load sharing module comprises load determining means for generating a signal which represents a load value corresponding to the power or current supplied by the respective power supply, and voltage control means for controlling the output voltage of the respective power supply to vary inversely with said load value at a first rate when the load value is below a threshold value, and for controlling the output voltage of the respective power supply to vary inversely with said load value at a second rate when the load value equals or exceeds said (first) threshold value. Said second rate is greater than said first rate.

Abstract: An electrically powered device includes at least one electrically powered component and a power source having at least two cells. One cell powers the electrically powered component and the remaining cells are held in reserve. A control circuit is connected to the electrically powered component and the power source. The control circuit includes a controller which generates a charge signal, a boost regulator circuit connected to the controller which receives power from the power source and generates a boost signal for conversion into a charge signal. A capacitor is connected to the controller and receives the charge signal and provides a predetermined voltage to the electrically powered component. A boost regulator circuit and the controller monitor the power source and draw power from one of the remaining cells held in reserve when the cell is fully depleted.

Abstract: An ambient energy collector for use in AC/DC applications is described. The ambient energy collector has at least one ambient energy collecting antenna system and a master control unit for operational control of the at least one ambient energy collecting antenna system. The ambient energy collector has a DC voltage boosting circuit for increasing an input voltage, a DC primer power source for powering up the voltage boosting circuit via the input voltage, at least one antenna system for collecting ambient energy, an energy collection circuit for converting and amplifying an AC voltage collected by the antenna of the at least one antenna system into a DC voltage, and an output circuit for providing a load with the DC voltage.

Abstract: A converter including a converter control for a wind turbine and a chopper, wherein the converter control includes a dynamic limit value which is allowable for a first tolerance time and a static limit value of the converter. Furthermore, an overcurrent module is provided which includes a limit value expander which is designed to increase the static limit value by a portion of the difference from the dynamic limit value as additional current, and a dynamic module which interacts with the limit value expander in such a way that overcurrents between the static limit value which is increased by the additional current and the dynamic limit value are routed in a first stage to the converter and in a second stage at least partially to the chopper, wherein a switch is made to the second stage after a second tolerance time.

Abstract: A battery load leveling system for an electrically powered system in which a battery is subject to intermittent high current loading, the system including a first battery, a second battery, and a load coupled to the batteries. The system includes a passive storage device, a unidirectional conducting apparatus coupled in series electrical circuit with the passive storage device and poled to conduct current from the passive storage device to the load, the series electrical circuit coupled in parallel with the battery such that the passive storage device provides current to the load when the battery terminal voltage is less than voltage on the passive storage device, and a battery switching circuit that connects the first and second batteries in either a lower voltage parallel arrangement or a higher voltage series arrangement.