Abstract: Disclosed herein are an AC/DC converter which is simple in circuit configuration, generates little ElectroMagnetic Interference (EMI) and has no transformer so that it can be reduced in weight and size and improved in AC/DC conversion efficiency, and an AC/DC conversion method using the same. The AC/DC converter includes a rectification circuit for converting a commercial AC (85-264V) voltage into a ripple AC voltage, a first control circuit for comparing the converted ripple AC voltage with a reference voltage and outputting a first pulse control signal as a result of the comparison, a first switching circuit for switching and outputting the ripple AC voltage from the rectification circuit in response to the first pulse control signal outputted from the first control circuit, and a first charge storage circuit for smoothing the ripple AC voltage outputted from the first switching circuit to convert it into a primary DC voltage.

Abstract: An n-buck cascade converter, where the DC conversion ratio is Un where U is the duty ratio. The converter comprises n inductors, n capacitors, (2n-1) diodes and a MOSFET transistor. The cascading configuration uses the minimum number of active switches while avoiding complex control circuitry. It is assumed that this converter operates in continuous condition mode, i.e., all the inductor currents never decay to zero. The corresponding formulae for the ripples in the capacitor voltages and the inductor currents are given. This allows designing in principle a specific converter following some specifications.

Abstract: The present disclosure is concerned with a multilevel converter including a transformer arrangement comprising at least two transformer units, each with primary and secondary windings and a transformer core structure. The latter are merged into one shared transformer core comprising at least one return limb that is part of the closed magnetic flux paths of the at least two transformer units. Sharing return limbs among individual transformer units, in particular when fed with primary voltage signals that have a certain phase shift between each other, helps to reduce the volume and weight as compared to an individual transformer core structure for each of the transformer units. The multilevel converter is beneficially used in railway traction applications.

Abstract: The invention relates to a modular converter system (2). According to the invention, the modular converter system (2) has a basic converter device (4) and at least one additional converter device (6), wherein said devices (4, 6) can be plugged laterally one beneath the other by means of their power-supply and load busbars (8, 10) and by means of a communication line (12). A modular converter system (2), which can be matched individually to any desired power output which may be required without a great deal of complexity, can therefore be achieved.

Abstract: Methods and apparatus of dynamic topology power converters are provided. One method includes monitoring at least one variable of the power converter and based on the at least one monitored variable, using a converter topology selected between at least a full-bridge converter topology and a half-bridge converter topology to achieve an efficient operation at a then current operational load.

Abstract: A power conditioner for supplying controlled power generated from a power source such as a fuel cell or a solar battery to a load. The power conditioner includes a main converter converting the output voltage of the power source; an auxiliary converter converting the output voltage of the main converter to a voltage that is supplied to BOP elements; and a direct connecting line connecting the output voltage of the power source to the auxiliary converter bypassing the main converter. Accordingly, because the voltage for the power to be supplied to the BOP elements is converted only once, the power loss can be significantly reduced compared to the power loss from a conventional power conditioner.

Abstract: A DC/DC power conversion device with smoothing capacitors including three column circuits share the smoothing capacitors to be connected in parallel, each column circuit have a plurality of circuits connected in series where two MOSFETs are connected in series between both ends of respective smoothing capacitors and LC serial bodies of capacitors and inductors with the same resonant cycle are disposed between the circuits at two middle terminals. Driving signals for the respective column circuits have the same driving cycle identical with the resonant cycle of the LC serial bodies, and are out of phase with each other by 2?/3(rad), and thus charge-discharge currents towards the smoothing capacitors are circulated among the column circuits and ripple currents flowing through the smoothing capacitors are reduced.

Abstract: A circuit for, and method of, changing transient response characteristics of a DC/DC converter module having an output rail pin and a trim pin and a distributed power conversion system incorporating the system or the method. In one embodiment, the system includes a reactive component coupled to the output rail pin and the trim pin of the DC/DC converter module and configured to interact with at least one network internal to the DC/DC converter module to change the transient response characteristics.

Abstract: A system for measuring performance of a voltage regulator module (VRM) attached to a microprocessor includes: a voltage transient tester (VTT) fixture (5) for setting different working voltage levels of the VRM; an oscillograph (2) for measuring transient voltage levels of the VRM, and generating a transient voltage waveform according to the transient voltage levels; an voltmeter (3) for measuring steady voltage levels of the VRM under thermal effects generated by the microprocessor; a direct current (DC) electronic load (4) for educing load currents from the VRM; and a measurement control module (10) installed in a computer (1) for generating load current control signals, controlling the DC electronic load to educe the load currents from the VRM according to the load current control signals, and generating a performance report of the VRM by integrating various measurement results.

Abstract: A DC converter is connected to a DC source on its input side. On the output side, the DC delivers a converted DC voltage to at least one electric consumer via a cable connection. To improve such a DC converter in that it has a comparatively simple structural design and is able to reliably convert high DC voltages even in the case of high power, and in such a way that the reliability of the converter is increased and cooling systems entailing high costs can be dispensed with, the DC converter comprises a plurality of DC converter components, each of said DC components being, on the input side, serially connected to the DC source and, on the output side connected in parallel to the cable connection so as to provide the converted DC voltage for the electric consumer.

Abstract: A power delivery system, and a method for operating it includes a plurality of power cells that are electrically connected to a multi-winding machine comprising one or more primary windings and a plurality of secondary windings such that each cell is electrically connected to one of the secondary windings and a plurality of the secondary windings are phase-shifted with respect to the primary windings. The method includes determining, for each cell in a set of the power cells, a carrier offset angle, and synchronizing, by the each cell in the set, a carrier signal to the secondary voltage for the cell based on the carrier offset angle determined for the cell. The carrier signal for each cell controls the timing of operation of switching devices within the cell.

Abstract: An output voltage detection circuit is provided for accurately detecting a secondary side output voltage based on a voltage induced to an auxiliary winding in an isolated switching power supply including a transformer having the auxiliary winding. A voltage waveform processing circuit (10-1) processes the waveform of the voltage induced to the auxiliary winding (7-3), a hold circuit (10-2) holds the voltage peak value after the processing, a secondary side current detection circuit (24) detects a period during which current passes through a secondary side winding (7-2), a correction circuit (22) performs correction to decrease the peak voltage which has been held by the hold circuit (10-2) during the period, and the corrected voltage is fed back to a control circuit (9). Meanwhile, a reset circuit (23) resets, for a fixed period after the current passes through the secondary side winding (7-2), the peak voltage having been held by the hold circuit (10-2).

Abstract: In a state where an abnormality of a boosting circuit is detected by monitoring a boosted voltage outputted from the boosting circuit, motor relays are turned to an off state when the boosted voltage outputted from the boosting circuit becomes less than a predetermined threshold value due to an action, such as the stopping of a supply of power source voltage to the boosting circuit. Therefore, there can be limited welding of the motor relays caused by an electric arc, which is generated when contacts of the motor relays, are separated.

Abstract: A method and apparatus for adaptively configuring an array of voltage transformation modules is disclosed. The aggregate voltage transformation ratio of the adaptive array is adjusted to digitally regulate the output voltage for a wide range of input voltages. An integrated adaptive array having a plurality of input cells, a plurality of output cells, or a plurality of both is also disclosed. The input and output cells may be adaptively configured to provide an adjustable transformer turns ratio for the adaptive array or in the case of an integrated VTM, an adjustable voltage transformation ratio for the integrated VTM. A controller is used to configure the cells and provide digital regulation of the output. A converter having input cells configured as a complementary pair, which are switched out of phase, reduces common mode current and noise. Series connected input cells are used for reducing primary switch voltage ratings in a converter and enabling increased operating frequency or efficiency.

Abstract: A method and apparatus for adaptively configuring an array of voltage transformation modules is disclosed. The aggregate voltage transformation ratio of the adaptive array is adjusted to digitally regulate the output voltage for a wide range of input voltages. An integrated adaptive array having a plurality of input cells, a plurality of output cells, or a plurality of both is also disclosed. The input and output cells may be adaptively configured to provide an adjustable transformer turns ratio for the adaptive array or in the case of an integrated VTM, an adjustable voltage transformation ratio for the integrated VTM. A controller is used to configure the cells and provide digital regulation of the output. A converter having input cells configured as a complementary pair, which are switched out of phase, reduces common mode current and noise. Series connected input cells are used for reducing primary switch voltage ratings in a converter and enabling increased operating frequency or efficiency.

Abstract: A distributed power supply is incorporated in a device including a plurality of PCB. An on-board power supply is provided in the distributed power supply. The on-board power supply individually supplies a secondary power to each PCB using a primary power. Each PCB includes a primary power supply monitoring circuit, a PCB internal power supply monitoring circuit, and a pulse generation circuit. The primary power supply circuit detects an abnormality in the voltage of in the primary power supplied to the on-board power supply. The PCB internal power supply monitoring circuit restarts the PCB when the abnormality is detected. The pulse generation circuit transmits a restart signal to the other PCBs in the device.

Abstract: A switched current power converter including an input power source, an output terminal, and a plurality of current stages. Each current stage includes a converter coupled to the input power source for providing a current, and a switch circuit for selectively coupling the current in such current stage to the output terminal. A control circuit selectively decouples the input power source from less than all of the current stage converters upon detecting a low load condition, thereby reducing circulating current losses and improving operating efficiency under low load conditions.

Abstract: An arrangement having a first converting element configured to convert an input current linearly into an auxiliary current, a second converting element configured to convert the auxiliary current into an output voltage, and a separating element configured to separate slow changes of the auxiliary current from fast changes of the auxiliary current, wherein the first, second, and separating elements are arranged as a dynamic control loop regulating the input current with the slow changes.

Abstract: A device and method for dynamically optimizing a power converter is disclosed. The dynamically optimized power converter unit includes a processor that maximizes efficiency of a power converter supplying energy to a load.

Abstract: Systems and methods of converting alternating current (AC) power into direct current (DC) power at an intermediate DC voltage are disclosed. Briefly described, one system embodiment comprises a separated front end rectifier system that provides intermediate voltage, direct current (DC) power to a plurality of loads, comprising a modular alternating current to direct current (AC/DC) rectifier coupled to an AC power system that converts received AC power to DC power at a rectified DC voltage, a rectified DC voltage bus coupled to the AC/DC rectifier and at least one modular direct current to direct current (DC/DC) conversion unit coupled to the rectified DC voltage bus and to an intermediate DC voltage bus.

Abstract: A power factor correcting power supply includes an input stage power converter and an output stage power converter. The input stage power converter includes a plurality of series connected boost switches and a power factor correction controller. The power factor correction controller may direct the operation of the boost switches with series interleave phasing to perform power factor correction and voltage regulation. The boost switches are supplied input voltage and input current from a power source. The input voltage is converted to a DC boost voltage by high frequency series interleaved switching of the boost switches. The DC boost voltage is converted to a DC output voltage by the output stage power converter. The DC output voltage is provided on a DC rail for a load of the power factor correcting power supply.

Abstract: The present invention is an apparatus for providing an uninterruptible power supply for an electronic device. The apparatus includes an AC-to-DC power supply that receives an external AC voltage supply and outputs a DC voltage to the electronic device. The power supply includes a bridge rectifier that rectifies the AC voltage from the external AC voltage supply, a boost power factor correction (PFC) converter that boosts the rectified voltage, and a line isolated DC-to-DC converter that changes the boosted voltage to the operating voltage range of the electronic device. The apparatus also includes an uninterruptible power supply (UPS) subsystem that contains, a controller that monitors the external AC voltage supply for interruptions, and a high voltage isolated DC-to-DC (HVDC) converter that supplies high voltage DC power directly to the PFC converter if the controller detects an interruption in the external AC voltage supply.

Abstract: A switched mode power supply assembly that has a plurality of power supply modules cyclically coupled to each other. Each power supply module has a synchronization control module for generating a synchronization control signal for a next neighboring module and for receiving a synchronization control signal from a previous neighboring module to ensure interleaved operation of all modules.

Abstract: Provided is a backup power supply comprising at least one DC/DC power electrically connected to a DC power source for taking DC current therefrom prior to providing regulated DC current, at least one AC/DC power electrically connected to an AC power source for taking AC current therefrom prior to providing rectified DC current, and a power control device including a power balance unit, a power output circuit, and a detection circuit each interconnected the AC/DC power and the DC/DC power. The power control device can combine DC current from both the AC/DC power and the DC/DC power prior to providing to an electronic device (e.g., computer). The invention can continue providing electricity to the computer in the event of not only a malfunctioning of the AC/DC or DC/DC power but also a power outage of either the AC or DC power source.

Abstract: A converter control apparatus comprises menas (14) (15) (17) for detecting output powers of a plurality of converters (100) connected in parallel to a load; an arithmetic circuit (19) for calculating an average output power of the converters on the basis of the detected output powers, and an output power control circuit (18) for controlling the output power of each converter such that it is equal to the average output power. This prevents non-uniformity from occurring in supplying the power from each converter to the load and hence prevents any of the converters from exhibiting an overload condition beyond a rating range.

Abstract: Multi-cell DC-DC power converters are described. In an adaptive version the isolated regulating multi-cell converter adaptively configures the input cells in a series connection to share the input voltage and in a parallel configuration to share the input current. Double-clamped buck-boost ZVS switching DC-DC, active clamped flyback, and flyback converter topologies may be used in the cells of the converter.

Abstract: A system includes an energy source configured for operating as a current limited source and a DC-to-DC converter or current switched inverter configured to receive current from the energy source and comprising a normally-on switch.

Abstract: A method and apparatuses are used for power conversion. The apparatus according to one embodiment comprises a plurality of power conversion modules (130—1, . . . 130—n), the plurality of power conversion modules (130—1, . . . , 130—n) being optionally controllable to function independently of each other to supply a plurality of systems (200—1, . . . , 200—n), function in an inter-relational mode in which at least one power conversion module from the plurality of power conversion modules (130—1, . . . , 130—n) drives a system and, upon a failure of the at least one power conversion module, at least another power conversion module from the plurality of power conversion modules (130—1, . . . , 130—n) will drive the system, and function in a scalable mode in which at least two power conversion modules of the plurality of power conversion modules (130—1, . . . , 130—n) are connected to provide an additive output.

Abstract: A power converter system for supplying an output voltage is provided. The power converter system is adapted to operate in a normal mode and a fault mode. The system comprises a plurality of bridges and a plurality of transformers. The system further comprises a plurality of dc link capacitors, each coupled across a corresponding bridge. The system also includes a controller adapted for, during the normal mode, switching each bridge with a respective normal phase shift. During the fault mode, the controller is adapted for switching each of the remaining ones of the bridges with a respective adjusted phase shift to generate the output voltage. During the fault mode, at least one of the plurality of bridges is bypassed.

Abstract: A multi-phase regulator that provides a smooth transition between DCM and CCM by employing partially synchronous rectification in which a duty cycle of a synchronous switch enable signal is gradually increased to 100%. The regulator includes a separate inductor, high-side switch, and synchronous switch for each phase. The high-side switches are controlled based on a separate PWM signal for each phase. Each PWM signal is provided by pulse width modulating the error signal, with each of the PWM signals having a different phase. During the partially synchronous rectification, the synchronous switch turns on when the high-side switch is off and the synchronous switch enable signal is asserted, and the synchronous switch is off otherwise. The synchronous switch enable signal has a frequency relative to the frequency of each of the pulse width modulation output signal such that good current sharing among the inductors of each phase is achieved.

Abstract: A power converter includes multiple phase circuits, each phase circuit includes a power switch for delivering power to an output of the power converter, a current sensor connected to the power switch for sensing a current in the power switch, a duty cycle controller having an output connected to the current sensor, and a low pass filter connected to the current sensor. The low pass filter is configured to produce a substantially direct current signal proportional to the average current in the power switch. Further, the duty cycle controller is configured to receive the direct current signal and control a duty cycle of the power switch in response to the direct current signal thereby balancing the currents in the phase circuits.

Abstract: A fault handling system for short circuit recovery in three-phase multiple-level inverter bridges, used to drive inductive loads, to assure a proper sequence for turning-off switches in the inverter bridge. Switches are selected for use in the inverter bridge so that outer switches toward the most positive and most negative bus voltage levels of the inverter bridge have lower transconductances than inner switches closest to an output phase of the inverter bridge. Additionally, driver cards driving outer switches utilize lower magnitude excitation control signals than driver cards driving inner switches. Driver cards driving outer switches, when detecting desaturation of an on-state switch, are set to automatically command the outer switch to an off-state, whereas driver cards driving inner switches wait for instructions from a controller before taking action.

Abstract: One embodiment of the invention relates to a switching converter having at least two converter stages, an output and an actuation circuit. The at least two converter stages each have power supply terminals for terminal to a supply voltage, a control terminal for supplying an actuation signal, an output terminal for providing an output current and a measurement terminal for providing a measurement signal which is dependent on the respective output current. The output is configured for connecting a load and providing an output voltage for the load, to which output the output terminals of the at least two converter stages are connected. The actuation circuit, to which the measurement signals and a signal which is dependent on the output voltage are supplied, provides the actuation signals. The converter stages are designed to provide a pulse-width-modulated measurement signal whose pulse duration is dependent on the respective output current.

Abstract: A method in connection with a network converter, and a network converter, the network converter comprising two or more network converter modules coupled in parallel, and first control means for controlling the network converter modules. The method comprises the steps of controlling the network converter modules by the first control means, preventing or allowing use of one or more network converter modules in order to reconfigure the network converter during operation of the network converter.

Abstract: A method for controlling at least two variable frequency drives connected in parallel. The method comprises, for each variable frequency drive, communicating a magnetizing current component value to a master controller, and receiving a speed demand, a flux demand, and an average magnetizing current component value from the master controller. The method also comprises determining a motor speed and a motor flux based on measurements of a stator voltage and current of a motor coupled to the variable frequency drive, determining a speed reference based on a torque current component value, and determining a flux reference based on the magnetizing current component value and the average magnetizing current component value. The method further comprises adjusting a torque current component based on the speed reference and/or adjusting a magnetizing current component based on the flux reference.

Abstract: Methods and apparatus for converting power from a power source are described. In one example embodiment, the method includes controlling multiple transformer and switchgear units coupled to a power source, and controlling multiple converter units connected in parallel. Each converter unit is coupled to a respective one of the transformer and switchgear units to form an individual thread. The transformer and switchgear unit and power converters are controlled so that the carrier waveforms for each individual thread are interleaved between each other over a carrier cycle.

Abstract: A power supply comprises at least one power switch adapted to convey power between input and output terminals of the power supply, and a digital controller adapted to control operation of the at least one power switch responsive to an output measurement of the power supply. The digital controller comprises an analog-to-digital converter providing a digital error signal representing a voltage difference between the output measurement and a reference value, a digital filter providing a digital control output based on a sum of previous error signals and previous control outputs, an error controller adapted to modify operation of the digital filter upon an error condition, and a digital pulse width modulator providing a control signal to the power switch having a pulse width corresponding to the digital control output.

Abstract: A power factor correction controller simultaneously controls several power converters to be operated at a critical conduction mode to improve the overall conversion efficiency and conversion power of the power factor corrector. The controller includes a primary power converter control circuit for feeding back an input voltage signal, an output voltage signal and a primary current signal, and outputting a primary gate control signal for controlling a primary power switch; at least one secondary power converter control circuit for receiving the primary gate control signal and outputting a secondary gate control signal for controlling a secondary power switch; and a phase splitter circuit for receiving the primary gate control signal to control a gate output driving circuit, so that the gate output driving circuit outputs the secondary gate control signal.

Abstract: A medium voltage power converter is provided that has an input transformer adapted to connect to a multi-phase power source, multiple low voltage drives each coupled to a respective set of secondary windings of the input transformer and operatively configured to provide a corresponding set of three-phase power outputs, and an output transformer. The output transformer has multiple input primary winding circuits each operatively coupled to the three-phase power outputs of a respective one of the drives, a plurality of output secondary winding circuits each disposed in relation to a respective input primary winding circuit, and a secondary winding connection arrangement in which each output secondary winding circuit has three secondary windings each of which is connected in series or in parallel with each other secondary winding of each other output secondary winding circuit to form a respective one of three phase-shifted outputs of the secondary winding connection arrangement.

Abstract: A method and an apparatus are used for power supply input connection.

Abstract: A power converter, and an associated method, for converting input power into output power. The power converter is capable of converting direct current input power as well as alternating current input power into direct current output power available for use to power an electrical load device, such as a consumer electronic device. The power conversion is performed at improved levels of efficiency, and less input power is dissipated as thermal energy.

Abstract: A power converter architecture interleaves full bridge converters to alleviate thermal management problems in high current applications, and may, for example, double the output power capability while reducing parts count and costs. For example, one phase of a three phase inverter is shared between two transformers, which provide power to a rectifier such as a current doubler rectifier to provide two full bridge DC/DC converters with three rather than four high voltage inverter legs.

Abstract: A method according to one embodiment may include providing a redundant feedback circuit. The method of this embodiment may also include coupling the redundant feedback circuit to a feedback control loop and decoupling a feedback circuit from the feedback control loop. The method of this embodiment may also include calibrating the feedback circuit. The method of this embodiment may also include recoupling the feedback circuit to the feedback control loop and decoupling the redundant feedback circuit from the feedback control loop. Of course, many alternatives, variations, and modifications are possible without departing from this embodiment.

Abstract: A switching regulator raises power from a USB terminal to 100 V, and performs the charging of an electrolytic capacitor. After the charging has been completed, a switching regulator drops the voltage to 5 V, and supplies the power to an amplifier. When the power consumed by the amplifier exceeds the maximum power to be supplied in accordance with the USB standard, the charge accumulated in the electrolytic capacitor is discharged, and for use, the switching regulator drops the power to 5 V. Thus, when the power consumed exceeds the maximum power to be supplied by the USB terminal, the amplifier can be driven without any problem.

Abstract: A distributed power supply is incorporated in a device including a plurality of PCB. An on-board power supply is provided in the distributed power supply. The on-board power supply individually supplies a secondary power to each PCB using a primary power. Each PCB includes a primary power supply monitoring circuit, a PCB internal power supply monitoring circuit, and a pulse generation circuit. The primary power supply circuit detects an abnormality in the voltage of in the primary power supplied to the on-board power supply. The PCB internal power supply monitoring circuit restarts the PCB when the abnormality is detected. The pulse generation circuit transmits a restart signal to the other PCBs in the device.

Abstract: There is provided a power source apparatus that includes a master circuit and a slave circuit provided in parallel and outputs an electric current that adds an electric current output from the master circuit and an electric current output from the slave circuit as a power-supply current. The master circuit includes: a main circuit side output section operable to output an electric current depending on a given voltage; a main circuit side reference power source operable to generate a reference voltage corresponding to a power-supply voltage that the power source apparatus is to output; and a main circuit side control section operable to supply the voltage corresponding to the reference voltage to the main circuit side output section in order to control the current output from the main circuit side output section.

Abstract: A two stage multiple output power supply device is capable of outputting programmable DC voltages onto multiple outputs. The first stage receives an AC supply voltage and outputs a DC supply voltage. The second stage includes a DC-ID controller and multiple DC-to-DC converters, each DC-to-DC converter receiving the DC supply voltage and capable of outputting a programmable DC voltage onto a conductor of a power cord to power an electrical device. For each DC-to-DC converter, the DC-ID controller receives information in an AC signal on the conductor, the information indicating the voltage and current requirements and the polarity of an electrical device connected to the power cord for that DC-to-DC converter. In response to the information, the DC-ID controller controls the DC-to-DC converter to set a magnitude, a polarity and a current limit for the programmable DC voltage that will be output by the DC-to-DC converter.

Abstract: A voltage/voltage converter for integrated circuits is characterized in that it presents a multistage symmetrical structure and comprises at least one input stage constituted by a clock booster circuit (CB) of symmetrical structure which delivers two output voltages, a voltage multiplier stage of symmetrical structure comprising two voltage multiplier circuits (CMi; CMip) respectively connected in two branches (B1; B2) of the converter and having applied respectively thereto the output voltages from the first stage, and an output stage (S) constituted by a multiplexer circuit (MX) having applied thereto the two output voltages from the voltage multiplier stage. The invention is particularly applied to EEPROMs and to low-voltage integrated circuits.

Abstract: In a switching power supply circuit, completion of discharging of a capacitance provided in a soft-start circuit requires a period longer than a cycle with which an activating/deactivating portion switches switching control operation of a driving portion (which performs switching control to turn on/off a switching device provided in a stepping-up DC-DC converter) between an activated state and a deactivated state. Moreover, the soft-start circuit is prevented from performing soft-start operation until discharging of the capacitance is completed.

Abstract: A single sleep mode controller which ensures that there is at least a corresponding minimum voltage level across capacitors when the corresponding regulators are turned off. In an embodiment, the sleep mode controller uses a single comparator which compares the voltages across capacitors in a time division multiplexed (TDM) manner, and initiates the charging operation for the capacitor if the voltage level falls below a corresponding minimum voltage level. The sleep mode controller continues the charging operation until the voltage level exceeds a corresponding upper threshold value. Due to the use of the single controller, power and/or space savings may be attained.