Abstract: The present invention discloses a lamp, which comprises a lamp seat installed in a base. The lamp seat is electrically connected with a circuit board. At least one USB interface includes a cartridge disposed in the base and a USB socket module disposed inside the cartridge. A wall of the cartridge, which is corresponding to the socket of the USB socket module, has at least one opening. The interface of an external USB data line can be passed through the opening and inserted into the socket of the USB socket module. The USB socket module is separated from the circuit board and electrically connected with the circuit board through cables. Therefore, the USB interface is reduced to a smaller size and requires less space for installation. Thus, the position for installing the USB interface has higher selectivity, and the overall esthetics of the base is improved.

Abstract: Disclosed are method and apparatus for controlling the supply of power in an electronic device are provided. The apparatus includes two or more batteries, a mutual charging prevention controller, a sequential discharging controller, and a controller that detects remaining capacities of the two or more batteries, charges a main battery of the two or more batteries in a single charging mode, when the remaining battery capacity of the main battery is less than or equal to a preset remaining battery capacity set to select a charging mode, and simultaneously charges the two or more batteries, when the remaining battery capacity of the main battery is greater than the preset remaining battery capacity.

Abstract: Example implementations relate to coupling volatile memory devices to a power source. In example implementations, data may be copied from a first volatile memory device on a memory module to non-volatile memory. The first volatile memory device may cease to be powered after data is copied from the first volatile memory device to non-volatile memory. After the first volatile memory device has ceased to be powered, data may be copied from a second volatile memory device on the memory module to non-volatile memory. The second volatile memory device may cease to be powered after data is copied from the second volatile memory device to non-volatile memory.

Abstract: The invention relates to a three-phase boost rectifier circuit and a control, method thereof, and an uninterrupted power supply which contains at least first battery packs BAT+, second battery packs BAT?, and a boost rectifier module; the boost rectifier module comprises a first bidirectional thyristor SCR1, a second bidirectional thyristor SCR2, a third bidirectional thyristor SCR3, a fourth bidirectional thyristor SCR6, a first unidirectional thyristor SCR4, a second unidirectional thyristor SCR5, a first inductor L1, a second inductor L2, a third inductor L3, a three-phase fully controlled rectifier bridge, a first capacitor C1 and a second capacitor C2. The invention can ensure the balance of positive and negative bus's voltage without the balancing device under battery operated boost mode, while improving the efficiency and reliability of the battery operated boost mode.

Abstract: A power supply, including a primary pre-converter, coupled to supplying mains, configured to receive an AC voltage at low frequency and output a high DC voltage, and further configured to receive the high DC voltage and to output the alternating current; a primary converter, disposed on a primary side of the power supply, coupled to the high DC voltage from the primary pre-converter; an isolating transformer to receive the high frequency AC voltage and output a high frequency secondary AC voltage, and to receive a high frequency secondary AC current and to output primary high frequency AC current; and an output converter, on a secondary side of the power supply, wherein the output converter is configured to receive high frequency AC voltage from the isolating transformer and to output a DC voltage of a first or second polarity to an output, and wherein the output converter is configured to receive DC current of a first or second direction from the output and to output a high frequency AC current to the isolat

Abstract: The present invention discloses a lamp device, which comprises a base, a lamp seat installed in the base and electrically connected with a circuit board, at least one USB interface, and a lamp shade hooding the lamp seat thereinside. The USB interface includes a cartridge disposed in the base and a USB socket module disposed inside the cartridge. The USB socket module is separated from the circuit board and electrically connected with the circuit board through cables. A wall of the cartridge has at least one opening. The interface of an external USB data line can be passed through the opening and inserted into the socket of the USB socket module. The USB interface is reduced to a smaller size and requires less space for installation. Therefore, the position for installing the USB interface has higher selectivity, and the overall esthetics of the base is improved.

Abstract: Systems and methods for controlling a UPS system to adapt to power availability requirements and to increase the efficiency of the UPS system are disclosed. The UPS system may include a modular UPS system or a parallel UPS system having a plurality of units. One method of controlling the UPS system includes obtaining actual power consumption by a load coupled to the UPS system, determining a log based power schedule in response to obtaining the actual power consumption and determining power availability for the UPS system in response to determining the log based power schedule. The method may further include adjusting a power capacity of the UPS system based on the power availability, by hibernating or activating at least one unit of the plurality of units of the UPS system.

Abstract: A remote-controlled photovoltaic string combiner is described that selects strings to be combined to a first photovoltaic output circuit or to a second photovoltaic output for the purpose of either controlling the charging of a battery connected to the first photovoltaic output circuit or for diverting current to a diversion load such as a grid-tie inverter. Strings are selected by energizing relays from one or other inverter such that when neither inverter is operating, all strings are deselected and both photovoltaic output circuits are de-energized.

Abstract: A power converter may be configured to power multiple output loads, including a main output load and at least one auxiliary output load. The power converter may include control circuitry that controls power delivery to output circuits coupled to the output loads. When the main output load is operating in a reduced power mode, the control circuitry may trigger the switching circuitry to increase the supply of power in order to increase the auxiliary voltages used to power the auxiliary loads if one or more of the auxiliary voltages drops below a threshold due to the main output load operating in the reduced power mode.

Abstract: A dual rail device includes a first power domain circuit coupled to a first power supply through a first header control switch and a second power domain circuit coupled to a second power supply. The first and second power supplies have different steady-state voltage levels. The first power domain circuit is interfaced to the second power domain circuit. The device also includes a power detector circuit for providing a control signal for the first header control switch responsive to a voltage level of the second power supply.

Abstract: An electrified vehicle has a battery pack comprising series-connected battery units providing a main voltage. To supply a lower voltage bus equally from all battery units, a plurality of DC/DC converters are powered by respective units and have their outputs in parallel. A central module has an outer loop controller generating a target current to regulate the bus voltage to a predetermined voltage and has an allocator distributing the target current into a plurality of allocated current commands according to respective states of charge of the battery units. A plurality of local controllers each adjusts a current of a respective DC/DC converter. Each local controller receives a respective allocated current command as a respective feedforward control variable. Each local controller uses an error between the bus voltage and the predetermined voltage to be integrated as a respective feedback control variable only when the error is above a threshold.

Abstract: Methods, devices, and systems for controlling energy generation interactions that bypass the grid may be provided. Flow control devices may be directly connected with one another independent of electrical connections to the utility grid. In some examples, the direct connections between the devices may enable sharing of power, controlling power flow over the direct connections, and/or recording relative power flows between the devices.

Abstract: A netlist of a multiple voltage circuit design having a plurality of power domains is established, then inter-power domain (IPD) paths traversing the circuit design are identified, according to whether they traverse multi-supply elements, or are clock paths capturing such a path. The netlist is then pruned to disable or remove cells or stages not traversed by an IPD path. A timing analyzer conducts a multi-domain timing analysis of the IPD timing paths in the pruned IPD netlist. Thereby, the circuit design is thoroughly tested according to the applicable ranges of voltage conditions without excessive runtime.

Abstract: According to one embodiment, in a storage cell system, cell lines each formed by connecting a prescribed number of storage cells in series are connected in parallel to form a storage cell module. Each unit is formed by connecting a prescribed number of storage cell modules in parallel. Outputs of a number of units corresponding to load capacity are linked in parallel and supplied to a load. At this time, current is limited to an extent that the storage cells are not damaged by interposing a current-limiting resistor in an output line of the storage cell module.

Abstract: A power management system is provided. The power management system includes a battery energy storage system (BESS) configured to obtain a state of charge (SOC) information, the state of charge (SOC) information including a charge state of the battery and a charging control unit configured to control charging or discharging of the BESS. The charging control unit is configured to compare a desired SOC and a measured SOC based on the obtained SOC information, and regulate a charging power value of a battery and a discharging power of the battery to match with the desired SOC, when as a result of comparison, the desired SOC and the measured SOC are different from each other.

Abstract: Provided is a fault isolation apparatus for an inverter configured for coupling to an external power supply. The apparatus includes a plurality of fault detection devices, each configured to (i) complete an electrical path between the inverter and the external power supply and (ii) detect a fault along its respective electrical path. The apparatus also includes a controller configured to instruct the fault detection device to complete its respective electrical path only when the path is devoid of the detected fault.

Abstract: A triboelectric power generator system uses a power converter to provide a controllable impedance between a triboelectric power generator and a load, in dependence on the triboelectric generator output. This enables improved power transfer even though the output generated by a triboelectric power generator can be irregular and fluctuates over time.

Abstract: A buck converter device with minimum off-time operation, the device comprising a comparator providing an output signal of a minimum off time, a first amplifier, a p-channel MOSFET whose gate is connected to the output of a first amplifier providing a signal threshold voltage to a positive terminal of a comparator, a second amplifier; and, a second p-channel MOSFET whose gate is connected to the output of a second amplifier providing a signal to a negative terminal of a comparator, and a capacitor element. A capacitor establishes a voltage whose rate of change is proportional to power supply Vdd, establishing a time to charge the capacitor to a threshold voltage proportional to (Vdd?Vref)/Vdd, and establishing a minimum off time on the output of a comparator.

Abstract: A generator has a surface structure relative to a base structure and capable of being positioned within a field of flow. The surface structure also has an electrogenerative portion positioned relative to the surface structure and the base structure. The electrogenerative portion is preferably a piezoelectric or electromagnetic structure, although other types of structures are known within the art. The field of flow exerts forces upon the surface structure which causes surface structure movement relative to the base structure through the electrogenerative portion. This generates electricity which causes movement in the surface structure.

Abstract: This display device includes a display control portion, a first power supply, a second power supply, and a connection control portion. The display control portion is capable of controlling display of a display panel and is configured to execute a predetermined control finish process before display control for the display panel is finished. The first power supply is configured to supply power supplied from an external power supply, to the display control portion. The second power supply is capable of storing power and is configured to supply power to a clock portion. The connection control portion is configured to connect the display control portion with the first power supply if disconnection of connection between the external power supply and the first power supply is not detected, and connect the display control portion with the second power supply if disconnection of the connection is detected.

Abstract: Various embodiments include a hybrid energy system that includes a gas-turbine generator configured to provide a up to a full-load power output and an energy storage device configured to store energy, and methods of operating such hybrid energy systems. A hybrid energy system includes a gas turbine generator or combined cycle gas turbine generator system configured to provide up to a full-load power output and a storage device for storing electric energy. The hybrid energy system includes a generator step-up transformer, in which the turbine generator and the storage device are electrically co-located on a low side of the step-up transformer. Methods of operation include controlling power output from the storage device and/or the gas-turbine generator to function as a spinning reserve during scheduled and unscheduled grid power demands to achieve economic and environmental performance advantages, and maintaining a charge state in the storage device.

Abstract: An arrangement for power management in an energy distribution system, a method for power management in an energy distribution system and an arrangement for implementing the method for power management in the energy distribution system, wherein a feed/return unit and a control unit are provided, where the control unit is configured to sense a present actual system state and to take the sensed actual system state as a basis for prompting energy output or energy intake (energy out/intake, energy feed/return) by the feed/return unit in order to allow continuous correction and dynamic support of an energy distribution system or in an energy distribution system.

Abstract: A power supply device includes first and second electric power lines, first and second boost converters, and an electronic control unit. The first and second electric power lines are connected to a load and a battery, respectively. The first and second boost converters each transfer electric power between the second and first electric power lines while changing a voltage of the electric power. The electronic control unit is configured to execute both-side driving when a temperature of the battery is equal to or more than a specified temperature and to execute one-side driving when the temperature is less than the specified temperature. The electronic control unit is configured to drive switching elements of the first and second boost converters with driving signals different in phase to execute the both-side driving, and to drive one of the first and second boost converters to execute the one-side driving.

Abstract: An image forming apparatus which can control to turn on/off a light emitting element depending on a sheet state on a manual sheet tray is provided. The image forming apparatus includes the manual feed tray on which the sheet is placed. The image forming apparatus is configured to be switchable between normal power mode and power saving mode. In the normal power mode, normal power is supplied. In the power saving mode, less power is consumed as compared to the power consumed in the normal power mode. The image forming apparatus includes a manual sheet feeding sensor which detects presence/absence of the sheet on the manual feed tray. The image forming apparatus includes a sheet length sensor S and a sheet length sensor L which include the light emitting element and a light receiving element to detect approximate sheet length of sheet placed on the manual feed tray in a conveying direction.

Abstract: The present invention relates to a power duplication apparatus for an HVDC system and a control method therefor, and the power duplication apparatus for an HVDC system comprises: a first independent power generator receiving first input power so as to generate and output first power; a second independent power generator receiving second input power so as to generate and output the first power; a first power supplier selectively receiving the first power output, respectively, from the first independent power generator and the second independent power generator so as to convert the first power into second power having a smaller size than that of the first power and output the same; a second power supplier for selectively receiving the first power output, respectively, from the first independent power generator and the second independent power generator so as to convert the first power into the second power having a smaller size than that of the first power and output the same; a first HVDC controller for receiv

Abstract: A power system with detecting function includes a power source, a power level detector, and a power floating detector. The power source includes multiple voltage sources for operations in multiple voltage domains, respectively. The power level detector is configured to constantly monitor the voltage level of each voltage domain. The power floating detector is configured to detect the presence of floating voltages in each voltage domain. Therefore, the present power system with detection function can guarantee stable operations and detect glitch attacks.

Abstract: The inventive technology, in certain embodiments, may be generally described as a solar power generation system with a converter, which may potentially include two or more sub-converters, established intermediately of one or more strings of solar panels. Particular embodiments may involve sweet spot operation in order to achieve improvements in efficiency, and bucking of open circuit voltages by the converter in order that more panels may be placed on an individual string or substring, reducing the number of strings required for a given design, and achieving overall system and array manufacture savings.

Abstract: Batteries having different form factors and power tools that are capable of using such batteries are described. In some embodiments, a power tool may use batteries having a post form factor as well as batteries having a slide form factor.

Abstract: A driving apparatus for an electric motor (11) comprising: an inverter (12) connectable to an electric motor (11) for supplying electrical current thereto; accumulator means (13) for providing a continuous electrical current, connected to the inverter (12) to provide electrical supply thereto; a transformer device (14) comprising first connection means (15) suitable to be coupled to a power grid to absorb power, and second connection means (16), suitable for coupling to the accumulator means (13). The transformer device (14) comprises: two buck converters (100, 200) connected in parallel to form an interleaved configuration; a boost converter (300) connected in series with respect to the buck converters; a control device connected to the converters (100) and configured to operate the converters so as to obtain a preset constant voltage at the ends of said second connection means.

Abstract: A current balancing circuit is disclosed comprising a first current detector configured to measure a first current flowing from a first supply voltage to a first load, and a second current detector configured to measure a second current flowing through an inductor from a second supply voltage to the first load. The first current is compared to a first threshold to generate an error signal, and the error signal is amplified by a gain to generate a second threshold. When the first current is above the first threshold and the second current is below the second threshold, a first switch is controlled to connect a first end of the inductor to the second supply voltage. When the second current is above the second threshold, a second switch is controlled to connect the first end of the inductor to a current sink.

Abstract: A system and method (“utility”) for providing power to an electrically powered device from alternate, redundant power sources via a single power cord. The utility is operable to provide redundant power to an electrical device having a power cord terminating in a standard plug. The utility is operable to sense a loss of power quality from one power source, and to switch a connection to another power source in response to the loss. The utility may be configured to match the form factor of a standard (e.g., NEMA or other electrical standard) duplex receptacle unit. The utility may be incorporated into a standard outlet box or may plug into a standard outlet box.

Abstract: Various embodiments include systems and methods of operating a hybrid energy system that includes a gas-turbine generator configured to provide a full-load power output and a storage device configured to store energy. The hybrid energy system includes a generator step-up transformer, wherein the gas-turbine generator and the storage device are electrically co-located on a low side of the generator step-up transformer. Methods of operation include controlling power output from the storage device and/or the gas-turbine generator during scheduled and unscheduled grid power demands to achieve economic and environmental performance advantages.

Abstract: A system may include a power source selector device connected to a plurality of power sources. The system may also include multiple power supply modules (PSMs). A first PSM, of the multiple PSMs, may be connected to a first output of the power source selector device. A second PSM, of the multiple PSMs, may be connected to a second output of the power source selector device. The first output of the power source selector device may be different from the second output of the power source selector device. The system may also include a controller device connected to the power source selector device and each of the multiple PSMs.

Abstract: In an embodiment, processor includes at least one logic circuit to generate information to be output from the processor; an input/output (IO) interface circuit coupled to the at least one logic circuit to receive and transmit the information; a voltage regulator to provide an operating voltage to the IO interface circuit; and a controller to control the voltage regulator to provide the operating voltage at an adjusted level from a nominal operating voltage based on a process variation of at least a portion of a die including the IO interface circuit. Other embodiments are described and claimed.

Abstract: A solar panel is disclosed that can be daisy-chained with other solar panels. The solar panel automatically generates output alternative current (AC) power that is in parallel with input AC power coming into the solar panel when the solar panel senses the input AC power so that the solar panel operates as a slave in this state. The solar panel automatically generates standalone AC output power when the solar panel fails to detect input AC power coming into the solar panel where the solar panel operates as a master in this state. The solar panel generates the standalone output AC power without any reliance on input AC power generated by a utility grid and/or other AC power sources external to the solar panel.

Abstract: System, especially for use in aircraft, for controlling at least one switching device (5, 5b, 5n) able to open or close the connection between at least one power source and at least one supplied device, and means for measuring the state of the power supply channel. The system comprises: at least two microcontrollers (1a, 1b) each able to emit a command intended for each switching device (5, 5b, 5n), said microcontrollers (1a, 1b) being connected to at least one portion of the means for measuring the state of the power supply channel; and a means (14, 14b, 14n) for determining the command to be transmitted, able to determine the command to be transmitted to each switching device (5, 5b, 5n) from the commands emitted by each microcontroller (1a, 1b) and intended for said control switch.

Abstract: An apparatus includes a first power supply switch, a second power supply switch, and a control circuit. The first power supply switch includes a P-channel Metal Oxide Semiconductor Field Effect Transistor (PMOSFET) having a drain coupled to a first power rail to receive a first power voltage, a source coupled to an output node, and a gate to selectively turn on or off the PMOSFET to supply the first power voltage to the output node or isolate the first power rail. The second power supply switch receives a second power voltage and passes it to the output node if the second power voltage is present. The control circuit cooperates with the first power supply switch to control the gate voltage to turn on the PMOSFET if the first power voltage is present and the second power voltage is absent, and turn off the PMOSFET if the second power voltage is present.

Abstract: A method involves operating an internal combustion engine connected to an electric generator, in particular a synchronous generator, during a network fault, in particular during an electric short-circuit, in a power supply network connected to the generator. A mechanical power delivered by the internal combustion engine is introduced into the generator and converted into electric power in the generator. The electric power is delivered to the power supply network, and the mechanical power delivered by the internal combustion engine is at least temporarily increased depending on the value of at least one operating parameter of the generator and/or the internal combustion engine prior to the network fault and/or during the network fault, preferably by an amount of a fuel introduced into the internal combustion engine being increased.

Abstract: The invention relates to a DC power distribution system for distributing DC power from a power supply device (3) to an electrical device (2). The power supply device is operable in a high power mode or in a low power mode for supplying a higher power or a lower power, respectively, to the electrical device via an electrical conductor (4), wherein the electrical device is switchable between a high power mode and a low power mode in which the electrical device consumes more power or less power, respectively. An electrical device control unit (11) controls the mode of the electrical device depending on the power supplied by the power supply device. This automatic control of the electrical device depending on the provided power can lead to a better balance between the power consumption and the power supply and, thus, to an improved efficiency of supplying power to the electrical device.

Abstract: The present invention relates to a system and method for decentralized energy resource based active virtual power energy management. According to an embodiment of the present invention, there is provided a system for decentralized energy resource based active virtual power energy management comprising: a meter data management device receiving a customer load profile from a customer; a resource aggregator obtaining energy generation resource state information and position information of a decentralized energy resource from at least one decentralized energy resource; and a virtual energy generation resource management device generating a decentralized energy resource load profile using the energy generation resource state information and providing energy required to the customer based on the customer load profile, the decentralized energy resource load profile and the position information.

Abstract: Activation of a release button is detected, where the release button is to separate a tablet computing device from a docking station while a mass storage device of the docking station is performing an operation. In response to the detection, power is maintained to the mass storage device from a battery of the docking station to complete the operation.

Abstract: An integrated circuit (IC) is disclosed herein for adjustable power rail multiplexing. In an example aspect, an IC includes a first power rail, a second power rail, and a load power rail. The IC further includes multiple power-multiplexer (power-mux) tiles and adjustment circuitry. The multiple power-mux tiles are coupled in series in a chained arrangement and implemented to jointly perform a power-multiplexing operation. Each power-mux tile is implemented to switch between coupling the load power rail to the first power rail and coupling the load power rail to the second power rail. The adjustment circuitry is implemented to adjust at least one order in which the multiple power-mux tiles perform at least a portion of the power-multiplexing operation.

Abstract: A power conversion device, which includes an insulation type full bridge converter and can switch a power transmission direction at a high speed, is provided. A DC/DC converter (10) constitutes a power conversion device, which operates as a first type converter that converts a voltage within a first range applied to a first input/output terminal pair into a voltage within a second range and outputs the voltage from a second input/output terminal pair or a second type converter that converts a voltage within the second range applied to the second input/output terminal pair into a voltage within the first range and outputs the voltage from the first input/output terminal pair, as a device that performs a predetermined state transition of the DC/DC converter (10) after waiting for a load current value of a primary or secondary side of a transformer (TR) becomes a value within a predetermined current value range.

Abstract: A rectifier is configured to convert a three-phase AC voltage to a 12-pulse DC voltage, drawing a 12-pulse AC current from a three-phase network. The rectifier may comprise a first interleaved phase-leg, a second interleaved phase-leg, and/or a third interleaved phase-leg. Respective interleaved phase-legs may comprise positive portions configured to conduct positive current from a transformer towards a load, and negative portions configured to conduct negative current from the load back to the transformer. The rectifier may be configured to sequentially cycle respective interleaved phase-legs into positive and/or negative 120 conducting states over a 360 degree cycle to output the 12-pulse DC voltage. For example, during a first 120 degree conducting state a positive portion of the first interleaved phase-leg may conduct positive current towards the load, while a negative portion of a different phase-leg may conduct negative current back to the transformer.

Abstract: An embodiment of the disclosure provides an electronic device including a power supply, an optical to electrical converter and a controller. The power supply outputs a first electric power. The optical to electrical converter receives an infrared light beam and converts the infrared light beam to a second electric power. The controller is coupled to the power supply and the optical to electrical converter. The controller operates in a first mode and a second mode. When the controller operates in the first mode, the controller is activated by the second electric power and after the controller is activated, the controller operates in the second mode and drives the power supply. Then, the controller receives the first electric power and stops receiving the first electric power for operation.

Abstract: A power supply device for supplying power to a load by combining a secondary battery and a capacitor includes a switching element which switches the supply of power to the load from the capacitor, a DC-DC converter which enables a voltage of the capacitor to be stepped up and supplied to the load and a control unit which enables power to be supplied to the load by pulse-controlling the switching element, controlling the DC-DC converter to output a pulse current alternately with the switching element and combining the alternately output pulse currents if the voltage of the capacitor drops below a minimum voltage capable of driving the load.

Abstract: A device is provided for intrinsically safe redundant current supply of field devices with a common current-limiting resistor in the mesh of the field device and with redundant current supply units. A current sensor can be provided in the mesh of the field device, the output signal of which sensor is connected to a controllable voltage source in the redundant current supply units.

Abstract: A method and apparatus for maximum power point tracking (MPPT). In one embodiment, the method comprises (i) modulating an operating voltage of a first DC source by a first perturbation function to generate a first output power; (ii) modulating an operating voltage of a second DC source by a second perturbation function to generate a second output power, wherein the first and the second perturbation functions are synchronized with one another and out of phase with one another; (iii) comparing the first and the second output powers; and (iv) adjusting MPPT set points for both the first and the second DC sources in the same direction based on a result of comparing the first and the second output powers.

Abstract: A bi-directional direct current to direct current converter includes a first inductor, a first switch, a first capacitor, a middle voltage point, a second inductor, a second switch, a second capacitor, a third switch and a fourth switch. A direct current voltage supply unit provides the bi-directional direct current to direct current converter with an input direct current voltage. When the third switch is turned on, and the fourth switch is turned on, and the first switch is turned off, and the second switch is turned off, then the first inductor and the second inductor store energy. When the third switch is turned off, and the fourth switch is turned off, and the first switch is turned on, and the second switch is turned on, then the first inductor and the second inductor release energy to the first capacitor and the second capacitor.

Abstract: A dockable device and a power method thereof are provided. The dockable device includes a main device, a main device battery, a connector, a switch and a voltage down-converter. The connector may be coupled to a docking device. The switch, coupled to the main device battery, is configured to be closed to provide power to the main device from the main device battery. The voltage down-converter is configured to provide power with a backup voltage to the main device, wherein the backup voltage is less than a discharge voltage output by a fully discharged main device battery.