Abstract: Systems and methods for management of a backup power system are described herein. At least one illustrative embodiment includes a backup power system configured to couple to a power source including a plurality of batteries, each comprising one or more cells, used to provide power if the power source fails, and processing logic coupled to the batteries and configured to monitor the state of each of the plurality of batteries and control the charging and discharging of each of the plurality of batteries. If the power source has not failed, the processing logic repeatedly and sequentially causes each battery to discharge while at least one of the remaining batteries remains fully charged, and monitors the power provided by the discharging battery. The processing logic determines the available energy stored in each fully charged battery based upon the power provided by the discharging battery during the time it takes to discharge.

Abstract: A vehicle includes a wireless communication device, a PLC processing device, and a communication control device. The wireless communication device wirelessly communicates with a wireless communication device external to the vehicle. The PLC processing device communicates with a PLC processing device external to the vehicle by utilizing, as a communication path, a charging cable and a charging port to which the charging cable is connected. The communication control device controls communication by the wireless communication device and communication by the PLC processing device, depending on the remaining amount of data to be transmitted.

Abstract: Systems and methods are described for controlling a power transfer rate in to and/or out of an energy storage device on-board a vehicle, such as a locomotive, during a power transfer opportunity. In one example, the method includes adjusting the power transfer rate based on a predetermination of a duration of the power transfer opportunity to match a duration of power transfer to the duration of the opportunity and achieve a specified state of charge.

Abstract: An automatic flow control apparatus includes a solar cell module that provides a received light signal, an energy storage module, a charging circuit, a regulating module, a control module, a rainfall detection module for generating a detected rainfall signal, and a pair of conductors. The control module converts the received light signal and the detected rainfall signal into measured light data and measured rainfall data, and stores a measured data set that includes the measured light data and the measured rainfall data. The controller determines based on at least the measured data set whether to output a control signal to the regulating module for controlling regulation of fluid flow.

Abstract: A detecting unit detects a usage state of a charge storage unit for each predetermined time period. A setting unit determines whether the usage state of the charge storage unit satisfies a predetermined condition for each time period, and when it is determined that the usage state satisfies the predetermined condition, sets a corresponding time period as a charge-use permitted time. A control unit determines whether a current time falls in the charge-use permitted time, and when it is determined that the current time falls in the charge-use permitted time, allows a discharging unit to discharge the charge storage unit.

Abstract: A system, a method, and an article of manufacture for determining an estimated battery cell module state indicative of a state of a battery cell module of a battery pack are provided. The method includes measuring at least one of a battery cell module voltage, a battery cell module current, and a battery cell module temperature. The method further includes determining the estimated battery cell module state of the battery cell module at a predetermined time based on an estimated battery pack state and at least one of the battery cell module voltage, the battery cell module current, and the battery cell module temperature. The method further includes storing a vector corresponding to the estimated battery cell module state in a memory.

Abstract: The method includes the simultaneous measurement of the current I, of the positive plate potential V+, and of the temperature T at the positive terminal of the battery, the determination of a temperature compensated value Vc+ of the positive plate potential and the use of the temperature compensated value Vc+ for estimation of the state of charge. This method is more particularly used for estimation of the state of charge of an alkaline battery having a NiOOH positive plate.

Abstract: This invention relates to a mobile electronic device and a power management method of a battery module thereof. The mobile electronic device includes a battery module, a charging/discharging module, and a control module. The charging/discharging module is coupled with the battery module. The control module is coupled with the battery module and the charging/discharging module. When the power supply is coupled with the mobile electronic device and the system time is not within a maintenance period, the control module controls the charging/discharging module to maintain capacity of the battery module within a first capacity range. When the power supply is coupled with the mobile electronic device and the system time is within the maintenance period, the control module controls the charging/discharging module to maintain the capacity of the battery module within a second capacity range.

Abstract: This invention generally relates to cable compensation, and is particularly applicable to cable compensation for an AC-DC voltage converter. In one embodiment, a cable compensation apparatus for compensating voltage drop of a cable connected between an electrical power supply and an electrical device comprises: a first capacitor; a timer circuit to time a predetermined time period; a current source to supply to said first capacitor during substantially said predetermined time period a first current substantially proportional to an output current outputted by the power supply to the cable; and a control circuit to adjust an output voltage outputted by said power supply to said cable dependent on a voltage on said first capacitor. The compensation in some embodiments is programmable by means of a discrete capacitor component.

Abstract: An apparatus for controlling a battery includes a capacitor for charging a voltage when the apparatus is on and discharging a voltage when the apparatus is off, a discharging circuit for discharging the voltage charged in the capacitor; a first switching unit for connecting or disconnecting the capacitor to/from a predetermined power source for the purpose of charging of the capacitor; a second switching unit for connecting or disconnecting the capacitor to/from the discharging unit; a voltage measuring unit for measuring a voltage charged in the capacitor; and a controller for calculating a power-off duration time according to the measured voltage. This apparatus may continuously calculate a power-off duration time of a battery pack.

Abstract: A method of testing a battery including several steps described herein is provided.

Abstract: A battery charging and electrical energy delivery system (25) that allows for separation of charging of a battery (23) and delivery of electrical energy to a first set of consumers (24). The battery may be charged via a first path (29) for connecting the battery with an energy source (22), while electrical energy may be supplied via a second path (30) (separate from the first path) from the energy source to the first set of consumers. The first set of consumers may also be powered by the battery via third path (31) e.g. if the energy source is off. A control unit (32) is adapted to control the supply of electrical energy along the first, second and third paths in response to a detected state of the energy source. A battery operated system (21a) including the battery charging and electrical energy delivery system (25) is also provided.

Abstract: A method for managing operation of a device, the method including performing using one or more processors and/or circuits in a handheld device, the one or more processors and/or circuits including a control device and one or more other devices, functions including receiving from the control device, one or more power setting signals indicative of a desired power level setting. The handheld device may operate utilizing a NORMAL power level setting in a normal mode, or a standby power level setting in standby mode. The standby power level setting may include a LOW power level setting and a sleep mode setting. One or more corresponding power adjustment signals may be generated based on the received one or more power setting signals. Power supplied to the handheld device may be adjusted based on the generated one or more corresponding power adjustment signals.

Abstract: A smart battery device includes an adapter, a switch electrically connected to the adapter, a battery pack electrically connected the switch, a sense resistor electrically connected to the battery pack and the adapter, an analog preprocessing circuit electrically connected to the battery pack and the sense resistor for digitizing analog signals measured at the battery pack and the sense resistor to form digital signals, and an adaptive control circuit electrically connected to the analog preprocessing circuit for receiving the digital signals, and electrically connected to the switch for selectively turning the switch on or off according to the digital signals.

Abstract: A method includes charging a battery to a first percentage of full capacity, where the first percentage of full capacity is above a pre-charge capacity and below the full capacity, monitoring, using a controller, the battery for a predetermined threshold and in response to the battery reaching the predetermined threshold, charging the battery to a second percentage of full capacity, where the second percentage of full capacity is greater than the first percentage of full capacity.

Abstract: If it is determined that excess power is generated based on overcharge information of a power storage device, a controller starts an operation of consuming the excess power by an excessive power consuming circuit. The controller counts elapsed time from the time point when the power consuming operation started, and if the counted elapsed time exceeds a minimum on-time set in advance, switches the excessive power consuming circuit from active to inactive state. The minimum on-time is set based on a pattern that is expected to cause generation of excessive regenerative power from an AC electric motor because of abrupt change in running status of an electric powered vehicle mounting a motor drive system.

Abstract: An input/output control device for a secondary battery mounted on a vehicle includes a current estimating unit estimating a battery current input to or output from the secondary battery based on an input/output power of the secondary battery and outputting an estimated value (estimated current (Is)), a current sensor measuring the battery current and outputting a measured value (measured current (It)), and an input/output control unit controlling the input/output power based on the estimated value and the measured value. The input/output control device controls the input/output of the secondary battery, using the measured current (It) as well as the estimated value (Is), and therefore can suppress more reliably significant increase in heating value of the secondary battery and its peripheral parts.

Abstract: A lithium-ion battery controlling apparatus includes a controller. The controller is configured to raise an upper-limit voltage in response to capacity degradation of a lithium-ion battery which is configured to supply power to a load and receive power from the load.

Abstract: A battery pack, a battery charger, a method for charging a battery pack are provided. The battery pack includes a secondary battery, a switch element for controlling charging and discharging the secondary battery, a controller for controlling the switch element, and a communication unit for performing with a battery charger. During charging, an initial charging is switched to a quick charging when a voltage of the secondary battery reaches a predetermined voltage, and the battery charger judges the battery pack as abnormal when the voltage does not reach the predetermined voltage within a timeout period after the initial charging is started. At least one of the timeout period and the predetermined is stored. At least one of the timeout period and the predetermined voltage to be read out is transmitted through the communication unit to the battery charger.

Abstract: Methods, systems, and apparatuses for determining battery state of health are provided. A battery that is substantially uncharged is charged with a substantially constant charge current. A time duration of the charging of the battery with the substantially constant charge current is determined. A state of health of the battery is estimated based upon the determined time duration and the constant charge current. The state of health of the battery may be calculated by multiplying the determined time duration with a value of the constant charge current to determine a total accumulated charge, and applying a predetermined factor to the accumulated charge to determine the state of health. The predetermined factor is a fixed percentage of the total charge capacity of the battery that corresponds to the battery type.

Abstract: A battery testing apparatus includes a charge circuit, a discharge circuit, a computer, and a control circuit. The charge circuit is coupled to a direct current (DC) adapter, the DC adapter charges a battery through the charge circuit. The discharge circuit is coupled to the battery and configured to discharge the battery. The computer records charge/discharge time and charge/discharge cycles of the battery, and calculates capacity and cycle life of the battery according to the time and cycles of charge and discharge. The control circuit has an input terminal coupled to the computer, and a plurality of output terminals respectively coupled to the charge circuit and the discharge circuit, the control circuit controls the charge and discharge circuits charging and discharging the battery.

Abstract: When a battery pack having an output voltage of 14.4 V that is connectable to an electric tool in a sliding manner is used as a power supply source for the electric tool that is connectable to a battery pack in an insertion manner and has a rated voltage of 12 V, the electric tool and the battery pack are connected to each other with an adaptor interposed therebetween. The adaptor has an FET that is switched at a predetermined duty of a predetermined frequency. The battery pack and the electric tool are connected or disconnected to or from each other by the switching operation, thereby dropping the output voltage of the battery pack. The voltage from the battery pack is detected. When the detected voltage is out of a predetermined value range, it is judged that the overcurrent or overdischarge has occurred. Then, the FET is turned off to stop the electric tool.

Abstract: Power consumption of an electronic device is measured by using circuitry within the electronic device to make power consumption measurements of the electronic device at predetermined time intervals. Each of the power consumption measurements is provided to a user of the device. This may involve incorporating each of the power consumption measurements in a debug printout generated by the electronic device. The measurements may be initiated by retrieving a parameter from a storage area within the electronic device, and initiating the power consumption measuring techniques in response to detecting that the retrieved parameter is in a predetermined state.

Abstract: System and method for estimating a time to recharge a rechargeable power source of an implantable medical device. A plurality of measured parameters relating to the implantable medical device and an external charging device are applied to a model of recharging performance and an estimate is provided to a patient, perhaps in advance of charging. Once charging has begun, updated estimates can be provided until charging is complete. Once charging is complete, the model may be updated to reflect any differences in the estimated time to complete charging and the actual time required to complete charging. The model may be based on limitations to the rate at which charge may be transferred to the rechargeable power source over a plurality of intervals.

Abstract: A battery charger capable of correcting the deterioration of a secondary battery left unattended in a charge state and capable of accurately grasping a residual capacity. A battery pack having a nonvolatile memory and a secondary battery cell is attached to the battery charger. Full charge capacity data indicating a chargeable capacity of the battery pack at full charge and a left-charged battery deterioration correcting table to correct the full charge capacity data in accordance with the number of charge cycles are read out from the nonvolatile memory. The charged state data is counted each time it is stored in the nonvolatile memory. A battery cycle deterioration correcting value is specified based on the number of charge cycles, and full charge capacity data is corrected using the specified correcting value. The full charge capacity stored in the nonvolatile memory is rewritten.

Abstract: An automotive power supply system comprises a battery module that includes serially connected battery groups each constituted with serially connected battery cells, integrated circuits each disposed in correspondence to one of the battery groups, a control circuit, a transmission path through which the integrated circuits are connected to the control circuit and a relay circuit via which an electrical current is supplied from the battery module. In response to a start signal instructing an operation start and received via the transmission path, each integrated circuit measures terminal voltages at the individual battery cells in the corresponding battery group and executes an abnormality diagnosis. If abnormality diagnosis results provided by the integrated circuits indicate no abnormality, the control circuit closes the relay, enabling supply of electrical current from the battery module and subsequently, the control circuit receives measurement results from the integrated circuits via the transmission path.

Abstract: A battery pack and a charging method for the same. The battery pack automatically regulates the full-charge voltage of a battery according to deterioration of lifespan of the battery. The battery pack includes: a rechargeable battery having a positive electrode and negative electrode; a switching module having a charge switching device and discharge switching device electrically connected to a high-current path of the battery; and a battery management unit electrically connected to the switching module to control the charge switching device and discharge switching device, electrically connected to the battery to measure an open-circuit voltage and a use time of the battery, determining whether the battery is deteriorated with reference to at least one of the open-circuit voltage and the use time of the battery, and setting a full-charge voltage of the battery when the deterioration of the battery is determined.

Abstract: A method is provided that achieves improved battery pack performance, system reliability and system safety while impacting only a small region of the battery pack/battery module, and thus having only a minor impact on battery pack cost, complexity, weight and size. The battery pack/battery module is designed such that the fusible interconnects associated with a single battery, or a specific fusible interconnect associated with a single battery, will be the last interconnect(s) to fuse during a short circuit event. The risk of sustained arcing for the predetermined interconnect(s) is minimized through the use of rapid clearing interconnects. As a result, the risk of damage and excessive heating is also minimized.

Abstract: A battery pack, or battery pack module, is provided that achieves improved battery pack performance, system reliability and system safety while impacting only a small region of the battery pack/battery module, and thus having only a minor impact on battery pack cost, complexity, weight and size. The battery pack/battery module is designed such that the fusible interconnects associated with a single battery, or a specific fusible interconnect associated with a single battery, will be the last interconnect(s) to fuse during a short circuit event. The risk of sustained arcing for the predetermined interconnect(s) is minimized through the use of rapid clearing interconnects. As a result, the risk of damage and excessive heating is also minimized.

Abstract: A method of operating a Real Time Clock (RTC) in a terminal is provided. The method includes detecting a clock signal transmitted to an RTC block when the main power supply is switched off, and supplying a power to the RTC block for its operation by charging and discharging the power periodically supplied from the backup battery according to the detected clock signal. A DC/DC converter connected to a backup battery is periodically switched on and off, and a capacitor is charged and discharged using the power of the backup battery, thereby avoiding supplying power from a backup battery continuously to an RTC block. Therefore, power consumption is reduced and a duration of time for maintaining RTC data is extended.

Abstract: A system for balancing the charge level of a plurality of electrically coupled battery units. The system configuration may utilize an architecture and/or methodology that is more appropriate for lower power applications. In particular, the present invention, in accordance with at least one embodiment, may provide a battery balancing system that implements low loss charge balancing circuits in a compact configuration suitable for a multitude of applications, such as smaller cell battery balancing. The charge balancing circuits may be incorporated within each battery unit.

Abstract: The present invention discloses a universal serial bus (USB) charging circuit, comprising: a charging path for charging a battery from a USB host; a charging switch located on the charging path; a current sensing circuit for sensing current information on the charging path; a maximum available current detection circuit for detecting the maximum available current from the USB host; and a loop controller circuit for controlling the charging switch so that the charging current on the charging path is substantially equal to the maximum available current detected by the maximum available current detection circuit, wherein the maximum available current detection circuit detects the maximum available current during circuit initialization and stores it.

Abstract: Disclosed herein are representative embodiments of methods, apparatus, and systems for charging and discharging an energy storage device connected to an electrical power distribution system. In one exemplary embodiment, a controller monitors electrical characteristics of an electrical power distribution system and provides an output to a bi-directional charger causing the charger to charge or discharge an energy storage device (e.g., a battery in a plug-in hybrid electric vehicle (PHEV)). The controller can help stabilize the electrical power distribution system by increasing the charging rate when there is excess power in the electrical power distribution system (e.g., when the frequency of an AC power grid exceeds an average value), or by discharging power from the energy storage device to stabilize the grid when there is a shortage of power in the electrical power distribution system (e.g., when the frequency of an AC power grid is below an average value).

Abstract: An electronic apparatus which is capable of correctly displaying the remaining usable time even if a discharged current of a battery pack is changed by an unexpected load due to an external apparatus connected. The electronic apparatus has a battery pack with a secondary battery mounted therein. A first remaining usable time of the electronic apparatus is calculated based on a consumed current of the electronic apparatus. A second remaining usable time of the electronic apparatus is calculated based on a discharged current of the secondary battery. The first remaining usable time calculated by the first remaining usable time calculating unit or the second remaining usable time calculated by the second remaining usable time calculating unit, whichever is smaller, is selected, and then a displaying unit displays the selected remaining usable time.

Abstract: A method for managing operation of a device is disclosed and may include performing the following using one or more processors and/or circuits in a handheld multistandard communication system, the one or more processors and/or circuits comprising a control device and one or more other devices: receiving from the control device, one or more power setting signals indicative of a desired power level setting. The handheld multistandard communication system may operate utilizing a NORMAL power level setting or a standby setting. The standby setting may include a LOW power level setting and a sleep mode setting. One or more corresponding power adjustment signals may be generated based on the received one or more power setting signals. Power supplied to the control device and/or the one or more other devices may be adjusted based on the generated one or more corresponding power adjustment signals.

Abstract: The present invention discloses a charger control circuit and a charger control method for controlling a charger having a transformer, the transformer including a primary winding and a secondary winding. The charger control circuit comprises: a power switch coupled to the primary winding; a switch control circuit controlling the operation of the power switch; and a detection circuit which generates a signal according to a voltage at a node between the power switch and the primary winding, and supplies the signal to the switch control circuit.

Abstract: A system, a method, and an article of manufacture for determining an estimated battery cell module state indicative of a state of a battery cell module of a battery pack are provided. The method includes measuring at least one of a battery cell module voltage, a battery cell module current, and a battery cell module temperature. The method further includes determining the estimated battery cell module state of the battery cell module at a predetermined time based on an estimated battery pack state and at least one of the battery cell module voltage, the battery cell module current, and the battery cell module temperature. The method further includes storing a vector corresponding to the estimated battery cell module state in a memory.

Abstract: A system, a method, and an article of manufacture for determining an estimated battery parameter vector indicative of a parameter of a battery are provided. The method determines a first estimated battery parameter vector indicative of a parameter of the battery at a first predetermined time based on a plurality of predicted battery parameter vectors, a plurality of predicted battery output vectors, and a first battery output vector.

Abstract: A battery pack is disclosed. The battery pack includes a battery, an impact sensor, a processor and a memory. The impact sensor is capable of generating an impact signal in response to a detection of an impact on the battery pack. The processor is capable of generating impact information based on the impact signal, and processor continues to count a number of charging times to the battery after the generation of the impact information. The memory is capable of storing the impact information and the number of charging times. The processor can refer to the memory to deliver a control command to a battery charger so that the battery can only be charged up to an allowable charge capacity smaller than a full charge capacity after an occurrence of an impact when the battery pack is attached to the battery charger. The charging to the battery stops when the number of the counted charging times reaches a predetermined number of allowable charging times that is allowed after the generation of the impact information.

Abstract: Disclosed is a method for measuring a battery charge level of a portable terminal having a removable back-up battery. The method includes determining that the back-up battery is connected in parallel to an main battery of the portable terminal, disconnecting the main battery from the back-up battery for a period of time in a cycle, and checking voltage levels of the main battery and the back-up battery to measure a charge level of each battery while the batteries are disconnected.

Abstract: One aspect of the invention involves: maintaining a record of how long a circuit operates in each of a plurality of different operating modes thereof, starting from a point in time at which a battery that powers the circuit is replaced; calculating for each of the operating modes as a function of the record a cumulative current drain from the point in time to a current time; and determining as a function of the cumulative current drains whether the battery is subject to a low voltage condition. Another aspect involves: monitoring a voltage of a battery; periodically determining whether the voltage of the battery is subject to a low voltage condition; and maintaining a count of the number of times that the determining results in a determination that the battery is subject to a low voltage condition.

Abstract: The present invention discloses a charging method for equalization charging a battery array consisting of at least two cells, comprising the following steps: (a) charging the cells of the battery array with a constant charging current; (b) detecting the cell voltages of the individual cells to judge whether some of the cell voltages have reached a pre-set safe reference voltage; (c) repeating the step (a) when determining that none of the cell voltages has reached the safe reference voltage, or maintaining at least one of the cell voltages at the safe reference voltage and reducing the charging current at the same time when determining that said at least one of the cell voltages has reached the safe reference voltage; (d) judging whether all of the cell voltages have reached the safe reference voltage when the charging current is reduced to a pre-set minimum charging current; and (e) reducing the charging current continuously below the minimum charging current and then terminating the charging operation when

Abstract: The present invention provides a battery rejuvenation method for rejuvenating a battery, which firstly pre-charges the battery for a short period of time and judges the battery condition by comparing the battery voltage to a preset reference voltage value, and then alternately performs an equalizing mode operation and a reconditioning operation to rejuvenate the battery until the battery voltage is not higher than the reference voltage value. The operations in equalizing mode and reconditioning mode could enhance the rejuvenating results by each other, which is not only dissolve the lead sulphate crystal, but also bring the electrolyte fluid to a well-distributed and fully-restored state. The present invention also provides a battery rejuvenation apparatus for rejuvenating a battery.

Abstract: A battery charging circuit is used by being connected to a direct-current power source. The battery charging circuit includes a control transistor, a backflow prevention transistor and a charging controller. The control transistor is disposed in a charging path between the direct-current power source and a battery, and is configured to control a direct-current voltage from the direct-current power source, and to output controlled direct-current voltage as a charging voltage. The backflow prevention transistor is disposed in the charging path, and is configured to output the charging voltage to the battery, and to be turned off when an electric current flows backward from the battery to the direct-current power source. The charging controller is configured to turn on the backflow prevention transistor when charging of the battery starts, and to turn on the control transistor after a fixed period of time elapses from a start of the charging.

Abstract: An integrated circuit battery sensor and system thereof are provided. The battery sensor includes a voltage sensor configured to sample a voyage of a battery and a buffer in electrical communication with the voltage sensor and configured for scaling the sampled battery voltage and outputting a voltage signal proportional to the sampled battery voltage; wherein the voltage sensor is further configured for isolating the buffer from the battery. The voltage sensor includes a first capacitor coupled to a positive potential terminal of the battery and a second capacitor coupled to a negative potential terminal of the battery. The battery sensor includes a first die including a first and second input terminal configured for coupling to the positive and negative potential terminals of the battery; and a second die including the voltage sensor, wherein the first and second die are electrically isolated from each other.

Abstract: Systems and methods for opportunistically charging a rechargeable power source of a portable electronic unit are provided. The system includes a primary inductance assembly energized by a main power source for inducing an electro-magnetic flux in a secondary coil assembly associated with a power source of the portable unit. Such electro-magnetic flux creates an electric current that is subsequently employed for charging the power source of the portable unit. A controller of the charging system can monitor state of charge, and notify a user when a recharge is required. Scavenging modes may also be employed for recharging the main power source and the rechargeable source of the portable unit.

Abstract: A battery charging controller according to the present invention controls battery charging in response to a charging-control signal sent from a CPU, and includes an starting controller which is started upon a detection of an insertion of an AC adapter, and which then starts a regulator at a predetermined timing by using a regulator control signal. The regulator is started upon a detection of the regulator control signal, and thereafter starts the CPU by using an starting signal. The CPU is started upon a detection of the starting signal.

Abstract: In one embodiment, a battery management system includes a charger controller for controlling a charging current of a battery according to a status of a load which is powered by the battery, and a counter coupled to the charger controller for determining a charging time according to such status. Advantageously, a first charging current is selected when the load is off. A second charging current that is less than the first charging current is selected when the load is on. Furthermore, a frequency of the counter is set to a first frequency when the load is off. The frequency is set to a second frequency that is less than the first frequency when the load is on.

Abstract: Method for treatment, in the form of regeneration, of an accumulator (160) having at least one cell, preferably lead batteries, in which a varying direct current from a power source (130) is applied in intermittent current supply periods, which are interrupted by pauses of substantially less current, preferably current free, the direct current being sufficient to generate gas in the accumulator. During the treatment process, process data is registered, which process data is used in order to control the treatment process.

Abstract: A smoothing circuit for realizing the miniaturization and the increase of integration scale of a circuit and for easily varying attack time and release time. This smoothing circuit comprises a capacitor, voltage comparator, charging circuit, and discharging circuit. The voltage comparator compares the terminal voltage of the capacitor with its input voltage and actuates the charging circuit or the discharging circuit according to a comparison result. The charging circuit charges the capacitor by intermittently supplying charging current. The discharging circuit discharges the capacitor by allowing discharging current to flow intermittently.