Abstract: A power conversion controller having a novel power factor correction mechanism, including: a normalization unit, used to generate a normalized signal according to a line voltage by multiplying the line voltage with a normalizing gain, wherein the normalizing gain is proportional to the reciprocal of the amplitude of the line voltage; a reference current generation unit, coupled to the normalization unit to generate a reference current signal by performing an arithmetic operation, wherein the arithmetic operation involves the normalized signal; and a gate drive signal generation unit, used to generate a gate drive signal, wherein the duty of the gate drive signal is determined by a voltage comparison of the reference current signal and a current sensing signal.

Abstract: The present disclosure is concerned with controlling distributing of electrical power in a power distribution region. To effectively control the distribution of power in the distribution region, the substation of the region is provided with a distribution controller or Intelligent Substation Control System (ISCS). The distribution controller is connected to various process devices, which in turn are connected to primary devices of the region. The process devices send data corresponding to the primary devices to the distribution controller, and the distribution controller includes a processor which proposes a set of actions based on the received data. Further, the distribution controller includes a coordinating device which selects the final action from the set of proposed actions. The final action is implemented on the primary devices of the distribution region.

Abstract: Advances in the arts are disclosed with novel methods and circuit systems for controlling power in an energy harvesting system. Techniques and related systems for controlling power output of an energy harvesting device provide for monitoring at least one power parameter at a power source and monitoring at least one power parameter at a load such as a storage medium. The power source output is adjusted in order to optimize energy harvesting and/or storage based on real-time performance parameters.

Abstract: Generally, this disclosure provides an apparatus, method and system for DC-DC conversion. The apparatus may include a switch network including a first plurality of switches configured to operate in a Buck mode to generate an output voltage that is less than an input voltage, and a second plurality of switches configured to operate in an Up mode to generate an output voltage that is greater than the input voltage. The apparatus of this example may further include controller circuitry configured to generate control signals to control the conduction state of the first plurality of switches and the second plurality of switches based on a variable reference signal indicative of power demands from a load coupled to the switch network.

Abstract: An electronic device for DC-DC conversion of an input voltage into an output voltage is provided. The electronic device includes a current mode control loop for controlling a sensed current of the DC-DC conversion by comparing a voltage level indicating a magnitude of the sensed current with a reference voltage level indicating the maximum admissible magnitude of the sensed current. The reference voltage level is dynamically adjusted in response to a change of an input voltage level.

Abstract: A receiving circuit is provided that can accurately detect a clock signal that has a single phase and a small amplitude. A receiving circuit includes an AC coupled circuit 22 that creates an AC coupling between a first end and a second end, a low-pass filter circuit 23, 25 that produces a third signal by applying a low-pass filtering on a second signal that is produced on the second end in response to a first signal that is applied to the first end, and a comparator 21 that inputs the second signal and the third signal.

Abstract: One embodiment of an apparatus to control and sense a voltage through a single node can include a comparator to monitor single node voltage, a transistor to discharge voltage through the single node and control logic. The control logic can have at least two operational phases when actively controlling the voltage through the single node. In a first phase, the control logic can configure the comparator to determine if the single node voltage is greater than a reference voltage. In a second phase, the control logic can configure the transistor to discharge voltage through the single node when the comparator has previously indicated that the single node voltage is greater than a reference voltage. The control logic can alternatively execute first and second phases to discharge the voltage to a predetermined level.

Abstract: An overvoltage protection circuit is arranged in an electronic device for providing a proper working voltage to the electronic device. The overvoltage protection circuit includes a first selecting circuit and a second selecting circuit connected in parallel to the first selecting circuit between a voltage input port and a voltage output port of the overvoltage protecting circuit. When an input voltage from the input port is less than a first value, the input voltage is output to the output port directly through the first selecting circuit, and when the input voltage is greater than the first value, the input voltage is output to the output port after the value of the input voltage is reduced through the second selecting circuit.

Abstract: An active load management system (ALMS) controllably restarts electrical service to service points in a utility service area after a power outage. The ALMS includes client devices installed at the service points and a central controller. In one embodiment, the controller associates numbers with the service points and stores the associations. Each service point may be associated with a unique number or a group of service points may share a number. After receiving notification that power is available, the controller determines a number and communicates the number to one or more of the client devices. Where the number was determined randomly, the client devices associated with the number may restart electrical service upon receipt of the number. Where the number was determined sequentially, a client device may determine its own random number and compare it to the received number. If a match occurs, electrical service can be restarted.

Abstract: An example controller for a power supply includes a drive signal generator and a compensation circuit. The drive signal generator is to be coupled to control switching of a switch included in the power supply to regulate an output voltage of the power supply in response to a sensed output voltage such that the output voltage of the power supply is greater than an input voltage of the power supply. The compensation circuit is coupled to the drive signal generator and is also coupled to output an offset current to adjust the sensed output voltage in response to the input voltage of the power supply.

Abstract: A device comprises a first power cell, a second power cell, a power factor correction module, a boost inductor switch circuit, and an output. The first and second power cells are configured to provide first and second currents in response to an input voltage. The power factor correction module is configured to continuously activate and deactivate the first and second power cells based on an input current level, on the input voltage, and on an output voltage. The boost inductor switch circuit is configured to disable the first power cell in response to the input current level being below a predetermined level. The output is configured to provide the output voltage based on the first and second currents when the input current level is above the predetermined level, and to provide the output voltage based on the second current when the input current level is below the predetermined level.

Abstract: A system and method for controlling power supply input filter oscillations is provided. The method includes utilizing a converter power circuit to generate a positive input resistance to counteract input filter oscillations, which are generated in response to normal converter negative input impedance and current-mode control operation. A controller controls the converter power circuit to generate the positive resistance utilizing a first input corresponding to the voltage applied to the converter input. A second input disables the converter power circuit based on completion of output capacitor charge, the first and second inputs being different.

Abstract: A boost circuit is used for power factor correction (PFC). In a low power application, transition mode control is utilized. However, switching frequency varies with different input voltages, and over a wide input voltage range, the switching frequency can become too high to be practical. To address this issue, a boost circuit is provided whose effective inductance changes as a function of input voltage. By changing the inductance, control is exercised over switching frequency.

Abstract: A voltage converter is coupled to an input voltage for boosting the voltage to a much higher level so as to take advantage of smaller capacitors due to the quadratic energy equation ½*CV?2. The voltage converter has at least one boost converter having an inductive element coupled to the input voltage. A high voltage storage element is coupled to the inductive element. A switching circuit of the at least one boost converter transfers stored electrical energy in the inductive element to said storage element. The switching circuit allows for the combining of the stored electric energy of the storage element with the input voltage to illuminate a flash element, or provide an increased amount of current temporarily to the input for applications such as last gasp.

Abstract: A direct current (DC) power supply apparatus includes an input unit configured to receive an outside DC power; a plurality of polarity correction units configured to correct the polarity of the outside DC power; a plurality of switch units installed to correspond to each of the plurality of polarity correction units; a detection unit configured to detect a flow of current of the plurality of polarity correction unit; and a control unit configured to determine a polarity correction unit, at which current of DC power flows, among the plurality of correction units based on a detection signal of transmitted from the detection unit, and control the switch unit corresponding to the determined polarity correction unit at an ON position such that the current of DC power flows through the switch unit which is controlled at the ON position.

Abstract: An example controller for a power converter includes an input voltage sensor, a current sensor, an oscillator, a timing and multiplier circuit, and a drive signal generator. The input voltage sensor receives an input signal representative of an input voltage and the current sensor senses a current in a power switch. The oscillator generates a signal having a switching frequency and the timing and multiplier circuit adjusts the switching frequency of the signal to be proportional to a value that is the input voltage multiplied by a time it takes the current in the power switch to change between two current values. The drive signal generator drives the power switch into the on state for an on time period and an off state for an off time period in response to the current in the power switch and in response to the signal having the switching frequency.

Abstract: The present invention discloses a buck switching regulator including a power stage, a driver circuit and a bootstrap capacitor. The power stage includes an upper-gate switch, a first lower-gate switch and a second lower-gate switch. The first upper-gate switch is electrically connected between an input terminal and a switching node. The first lower-gate switch is connected in parallel with the second lower-gate switch, both of which are electrically connected between the switching node and a first node. The driver circuit controls the operation of the upper-gate switch and the first lower-gate switch. The bootstrap capacitor is electrically connected between a boot node and the switching node, wherein the boot node is electrically connected to a supply voltage. When a voltage across the bootstrap capacitor is smaller than a reference voltage, the second lower-gate switch is turned on to charge the bootstrap capacitor from the supply voltage.

Abstract: A method for maintaining reliability of a distributed power system including a power converter having input terminals and output terminals. Input power is received at the input terminals. The input power is converted to an output power at the output terminals. A temperature is measured in or in the environment of the power converter. The power conversion of the input power to the output power may be controlled to maximize the input power by setting at the input terminals the input voltage or the input current according to predetermined criteria. One of the predetermined criteria is configured to reduce the input power based on the temperature signal responsive to the temperature. The adjustment of input power reduces the input voltage and/or input current thereby lowering the temperature of the power converter.

Abstract: A voltage reference generation circuit includes a current supply circuit and a core circuit. The current supply circuit is arranged to provide a plurality of currents. The core circuit is coupled to the current supply circuit, and arranged to receive the currents and accordingly generate a voltage reference. The core circuit includes a first transistor, a second transistor and a third transistor, wherein the first transistor and the third transistor generate a first gate-to-source voltage and a third gate-to-source voltage, respectively, according to a first current of the received currents; the second transistor generates a second gate-to-source voltage according to a second current of the received currents; and the voltage reference is generated according to the first gate-to-source voltage, the second gate-to-source voltage and the third gate-to-source voltage.

Abstract: A method of controlling a photovoltaic system includes providing a photovoltaic device having a variable DC voltage output and a variable DC current output. The photovoltaic device has a combination of a voltage output level and a current output level corresponding to a maximum power point. A DC power supply is connected in a parallel and/or series combination with the photovoltaic device. A DC load is connected in series to the combination of the DC power supply and the photovoltaic device such that the load is powered by the combination. A characteristic of the DC power supply is adjusted such that the voltage output and the current output of the photovoltaic device substantially match the voltage output level and the current output level corresponding to the maximum power point or other desired power point.

Abstract: A driver circuit, in accordance with one example, includes a controllable current source operably coupled to the load and configured to sink or source a first current in accordance with a control signal. A controllable switch is responsive to an input signal, operably coupled to the current source, and configured to take over, or not, the first current in accordance with an input signal. The first current is directed as a load current through the load when the controllable switch is driven into a blocking state. The first current is directed through the controllable switch when the controllable switch is driven into a conducting state thus bypassing the load. An input signal includes a first series of pulses defining the desired load current waveform in accordance with a desired modulation scheme.

Abstract: Systems and methods are provided for delivering energy from an input interface to an output interface. An electrical system includes an input interface, an output interface, an energy conversion module coupled between the input interface and the output interface, and a control module. The control module determines a duty cycle control value for operating the energy conversion module to produce a desired voltage at the output interface. The control module determines an input power error at the input interface and adjusts the duty cycle control value in a manner that is influenced by the input power error, resulting in a compensated duty cycle control value. The control module operates switching elements of the energy conversion module to deliver energy to the output interface with a duty cycle that is influenced by the compensated duty cycle control value.

Abstract: A system comprises an AC/DC adapter having a connector. The system also comprises a portable computer that receives said connector. The portable computer comprising a delay circuit coupled to a power transistor that is coupled in parallel with a resistor. The delay circuit causes the power transistor to activate following a time delay after current from the adapter begins to flow through the resistor. As a result of a user beginning to remove the connector from the portable computer, a control transistor is activated to reset the delay circuit.

Abstract: A power supply system includes a battery and a power management system. The power management system is coupled to the battery and to an external power source that is operable to charge the battery using a first charge level. The power management system is operable to determine that a battery power level of the battery is greater than a first predetermined level that depends on a battery storage option and, in response, disable power from being supplied from the external power source such that power is supplied from the battery until the battery power level is below the first predetermined level. The power management system is also operable to determine that the battery power level of the battery is less than the first predetermined level and, in response, charge the battery with a second charge level that is less than the first charge level until the battery power level is above a second predetermined level that depends on the battery storage option.

Abstract: Methods, apparatus and media for controlling a switching circuit controlling an amount of power drawn from an energy converter, to optimize the amount of power drawn from the energy converter. An output voltage and an output current of the energy converter are measured to produce signals representing converter output voltage and current. Converter power is calculated from the product of the converter output voltage and current. A perturb voltage is calculated as a decreasing nonlinear function of the converter power. A new reference voltage signal representing a desired converter output voltage is produced in response to a previous reference voltage signal and the perturb voltage. The reference voltage signal is used by the switching circuit to adjust the power drawn from the converter to achieve the desired converter output voltage.

Abstract: The embodiments of the present invention disclose a single board energy-saving device, which includes: a power calculation module, configured to detect the input current of the single board, and calculate the real-time power of the single board according to the detected input current and a previously measured and obtained input voltage of the single board; a single board energy-saving control module, configured to determine the load condition of the single board according to the real-time power of the single board and send a voltage adjustment command according to the load condition; a power supply adjustment module, configured to receive the voltage adjustment command and adjust the bus voltage of the single board according to the voltage adjustment command. The corresponding embodiments of the present invention also disclose a single board energy-saving method and a single board. Through the foregoing technical solutions, energy-saving is realized for the single board.

Abstract: A solar device is provided. The solar device includes a solar module configured to absorb solar energy to convert the solar energy to electrical energy, a DC converter configured to detect an input voltage output from the solar module and outputs a DC voltage corresponding to a maximum power point through the detected input voltage, an interface unit configured to transmit data including the input voltage detected from the DC converter and the DC voltage corresponding to the maximum power point, a data combiner configured to combine and transmit data on the solar module with the data received from the interface unit, a data synthesizer configured to remove a DC voltage offset from the data received from the data combiner, and a data controller configured to track a maximum power point using data from which the DC voltage offset has been removed.

Abstract: A method includes searching for a point of maximum power based on a systematic load variation, setting the point of maximum power as the operating point of the photovoltaic generator, and tracking the operating point based on a load variation with a narrow variation range. The method also includes analyzing operating variables of the photovoltaic generator to determine the level of probability that the operating point deviates from the point of maximum power, selectively interrupting the tracking and carrying out another search to determine the point of maximum power as a function of the analysis of the operating variables, and setting the point of maximum power as the operating point, and resuming the tracking. The method further takes into account previous searches carried out in the presence of comparable operating variables to determine the probability.

Abstract: A power circuit is provided. The power circuit comprises an input terminal configured to receive a DC input, a DC-DC converting module configured to convert the DC input received at the input terminal into one or more DC outputs at predefined ratings, and a parameter configuring module configured to configure parameters of the DC-DC converting module to match with the DC input received at the input terminal based on different DC inputs. The DC-DC converting module is further configured to operate at the parameters configured by the parameter configuring module, and an output terminal configured to output the one or more converted DC output.

Abstract: This disclosure describes an invention that is a basic charge recycling gate 70 that includes a precharge node 75, a output charging network 78, an output pre-charge and null propagate network 77, an evaluation network 76, a first time varying power supply TVS0, a second time varying power supply TVS2, and a keeper circuit 79. Additionally, this disclosure describes an invention that is a time varying power supply 130 that includes a resonator circuit 131, an amplitude and power check circuit 135, one or more overshoot and an undershoot voltage clamps 1105 and 112, exciter circuits 137 and 136, and current monitor circuits 138 and 139. In addition, the invention includes frequency self tuning with the amplitude and power check circuit 135, capacitor banks 132 and 134, and the inductor tap select controller 133. Amplitude self tuning is provided by the amplitude sample and compare circuit 144. Further, a phase shift control circuitry 150 is also provided.

Abstract: Methods and apparatuses are disclosed for power conversion for fuzes and other electrical power consumers. A current monitor coupled to a power source signal generates a source current indicator. A controller generates a control signal responsive to the source current indicator. A filter well is coupled to the power source signal. An inductive switch circuit switchably grounds a rectified inductive load coupled to an output side of the filter well in response to the control signal, developing a pulsed power signal. A resonance rectifier presents substantially lossless resistive impedance for the pulsed power signal and rectifies the pulsed power signal to charge a charge storage device and generate a power output signal. The filter well, the inductive switch circuit, and the controller maintain the source current indicator within a predetermined current range by filtering the pulsed power signal and adjusting the control signal's frequency responsive to the source current indicator.

Abstract: A voltage regulating device includes a connector, a slot, a voltage regulating circuit, and a control module. The connector is obtains an initial voltage from an external power supply. The slot is configured for electrically connecting to a load. The voltage regulating circuit is connected between the connector and the slot. In accordance with user input into a keyboard connected to a control microchip as to a voltage level required, the voltage regulating circuit converts the initial voltage to a required test voltage and outputs the required test voltage to the load by the slot. The control microchip controls the voltage regulating circuit to convert the initial voltage into the required test voltage.

Abstract: A method, system and apparatus for controlling a pulse width modulator (PMW) converter for direct AC/AC conversion and/or AC voltage regulation. According to some embodiments of the invention, an output voltage may be provided, independent of the input voltage quality, thereby avoiding or minimizing power company irregularities, brownouts and the like. Embodiments of the present invention may be useful, for example, for use in connection with motors and motored devices or other applications.

Abstract: In a DC/DC converter, a first operation section calculates a first operation value, based on a difference voltage between an instruction value for a high-voltage-side voltage and a detected value of a high-voltage-side voltage, a second operation section calculates a second operation value, based on a difference voltage between a voltage instruction value for a charge-discharge capacitor and a voltage detected value of the charge-discharge capacitor, and a switching control section obtains a conduction ratio, based on the first operation value and the second operation value, and controls, based on the conduction ratio, switching operations of first to fourth semiconductor circuits, thereby controlling the high-voltage-side voltage, and the voltage of the charge-discharge capacitor.

Abstract: The present invention discloses a bi-directional switching regulator and its control circuit, wherein the bi-directional switching regulator converts an input voltage to an output voltage in a power supply mode, and it includes: a power stage including an upper gate switch, a lower gate switch and an inductor coupled to a common switching node, wherein the inductor is coupled to the input voltage; a load switch coupled between the output voltage and the upper gate switch; and a driver circuit controlling the load switch to adjust an output current flowing through the load switch according to current information at an input terminal of the input voltage.

Abstract: A wide input voltage power supply circuit for a load includes a first stage and a second stage. The first stage includes a linear regulator circuit configured to maintain an output voltage at a predetermined output voltage level. The linear regulator includes an input for shutting the linear regulator off when an input voltage exceeds a predetermined shut off threshold. The second stage includes a high voltage detection circuit coupled to the input of the linear regulator. The high voltage detection circuit is configured to detect the level of the input voltage and to shut the linear regulator off when the input voltage exceeds the predetermined shut off threshold. An under voltage lockout circuit may be included, the under voltage lockout circuit configured to set a minimum turn-on voltage for the load.

Abstract: A power converter is configured to transfer energy from a photovoltaic (PV) array to a DC bus internal to the power converter. The power converter executes a modulation module to selectively connect one or more switching devices between the output of the PV array and the DC bus. The power converter is configured to operate in multiple operating modes. In one operating mode, the converter operates with a fixed modulation period and a variable on time, and in another operating mode, the converter operates with a variable modulation period and a fixed on time. The improved power converter provides highly efficient low power energy capture, improving power efficiency and enabling energy capture in low light conditions with reduced converter losses.

Abstract: Disclosed herein is a power supply apparatus, including: a first switch configured to change over electric connection to an electric power generation section; a voltage sensor configured to acquire a magnitude of an input voltage; a control section configured to control the first switch in response to an input from the voltage sensor; and a voltage conversion circuit configured to convert an input voltage into a desired voltage and output the converted voltage, wherein, when the input voltage is lower than a voltage necessary for starting up of the voltage conversion circuit, switching on and off of the first switch are repeated until the input voltage reaches the voltage necessary for starting up of the voltage conversion circuit.

Abstract: A boost circuit is used for power factor correction (PFC). In a low power application, transition mode control is utilized. However, switching frequency varies with different input voltages, and over a wide input voltage range, the switching frequency can become too high to be practical. To address this issue, a boost circuit is provided whose effective inductance changes as a function of input voltage. By changing the inductance, control is exercised over switching frequency.

Abstract: The response characteristics of an output signal and current consumption are kept constant. A drive circuit for outputting an output signal having a voltage determined by a logic of an input signal includes a constant voltage generating section generating a constant bias voltage, a CML circuit outputting the output signal having the voltage determined by the logic of the input signal, where an amplitude of the output signal is determined by a constant current flowing through the CML circuit and a potential of the output signal is determined by the bias voltage, an adjustment constant current source that allows a constant current to flow out from a bias voltage output end of the constant voltage generating section, and a current setting section that sets in advance the constant current flowing into the adjustment constant current source, according to the constant current flowing through the CML circuit.

Abstract: Some embodiments include an electrical surge protector. Other embodiments of related systems and methods are also disclosed.

Abstract: Disclosed are a maximum power point tracker, a power conversion controller, a power conversion device having an insulating structure, and a method for tracking maximum power point. The power conversion device includes: a DC/AC converter including a primary DC chopper unit having a primary switch, a transformer, and an AC/AC conversion unit including a secondary switch; a current detector detecting current from an input stage of the DC/AC converter and providing a detected current value; a voltage detector detecting a system voltage from an output stage of the DC/AC converter; and a power conversion controller generating a primary PWM signal to be provided to the primary DC chopper unit and secondary first and second PWM signals, having the mutually opposing phases, to be provided to the AC/AC conversion unit by using the detected current value and the system voltage.

Abstract: A step-down converter is provided. The step-down converter includes a DC-DC converter including a boost capacitor and an NMOS transistor, the DC-DC converter converting an input direct current (DC) voltage to an output DC voltage; and an electric discharge circuit which adjusts the output voltage to be less than or equal to the input voltage.

Abstract: An LD driver is disclosed, which improves the rising and falling times of the driving current for the LD. The LD driver includes an inverting amplifier, an emitter follower connected in down stream of the inverting amplifier, a driving transistor driven by the emitter follower, and a current-mirror circuit connected in series to the inverting amplifier. The mirror current generated from the current flowing in the inverting amplifier is provided to the output of the emitter follower served for discharging the input capacitance of the driving transistor.

Abstract: Circuitry and methodology for tracking the maximum power point (MPP) of a solar panel is disclosed. The voltage and current generated by the solar panel are monitored and used to generate a pulse signal for charging a capacitor. The changes in the voltage and current generated by the solar panel are also monitored, and that information is used to generate a pulse signal for discharging the capacitor. The charging and the discharging pulse signals are used to charge and discharge the capacitor. A reference signal indicative of the charge level of the capacitor is generated. As the current and voltage generated by the solar panel approach the maximum power point (MPP), the frequency of the discharging pulse signal becomes progressively higher, so that the capacitor charging occurs in progressively smaller increments. When the MPP is reached, the reference signal level becomes steady because the charge level of the capacitor becomes steady.

Abstract: A power system is disclosed. The power system comprises a plurality of power supply units, a voltage sharing bus, and a current sharing bus. The sharing bus is used to transmit a sharing voltage, and the current sharing bus is used to transmit a first current reference value. Each of the power supply units comprises: a power converter, a feed-forward control (FFC) circuit, and a feedback control (FBC) circuit. The feed-forward control circuit is used to generate a second current reference value according to a difference between an input voltage of the power converter and the sharing voltage. The feedback control circuit is used to generate a current compensation value according to the second current reference value and the first current reference value. The power converter can adjusts the output current thereof in accordance with the current compensation value.

Abstract: A maximum power point tracking method is provided. The method includes temporarily determining a next voltage command using voltage and power measured at current and previous time points. When an increase or decrease in voltage command is continued predetermined times or more, it is decided that the next voltage command temporarily determined to be increased is decreased or that the next voltage command temporarily determined to be decreased is increased. The output voltage of a solar cell is regulated based on the decided next voltage command.

Abstract: A buck converter includes a power supply unit, two MOSFETs and a delay circuit. The PWM module is coupled to the gates of the two MOSFETs to alternatively turn on the two MOSFETs. The delay circuit is coupled between an output terminal and an input node of the PWM module for making sure that a voltage applied to the PWM module is after a voltage applied to a drain the MOSFETs.

Abstract: According to one embodiment, a power supply stabilizing circuit includes at least one bias voltage generation circuit and at least one voltage supply circuit. The at least one bias voltage generation circuit is configured to compare a reference voltage and a signal corresponding to a bias voltage which is generated from an unstable voltage, thereby generating the bias voltage. The at least one voltage supply circuit is disposed near a functional circuit, is connected to the functional circuit by a wiring line, and is configured to stabilize the unstable voltage, based on the bias voltage which is supplied from the at least one bias voltage generation circuit, and to supply a stabilized voltage to the functional circuit.

Abstract: A synchronous buck DC/DC converter to perform an improved switching operation by adjusting a variable resistor is provided. The synchronous buck DC/DC converter includes a switching unit for switching two PWM signals inverted with a dead time and outputting the PWM signals, a smoothing circuit for outputting DC power using a waveform output from the switching unit as an input, a variable resistor connected to the switching unit and adjusting a switching time of the waveform output from the switching unit, and a variable resistor controller for sensing a current from an output terminal of the smoothing circuit and setting the resistance of the variable resistor to a resistance corresponding to the sensed current.