Abstract: A gate driving power source device can be miniaturized by sharing power source units, and a large current can be prevented from locally flowing in a single chip even when a short-circuit failure occurs in a multi-phase conversion circuit included in a power conversion device. There is provided a shared power source unit supplying a shared DC power source to a gate drive circuit provided in any one of a plurality of lower arms of multi-phase conversion circuits or any one of a plurality of upper arms of the multi-phase conversion circuit and gate drive circuits provided in upper arms or lower arms of other conversion circuits.

Abstract: An embodiment voltage converter includes a first transistor connected between a first node of the converter and a second node configured to receive a power supply voltage, a second transistor connected between the first node and a third node configured to receive a reference potential, a first circuit configured to control the first and second transistors, and a comparator configured to compare a first voltage with a threshold, the first voltage being equal, during a first period, to a first increasing ramp and, during a second period, to a second decreasing ramp, the threshold having a first value during the first period and a second value during the second period, the first and second values being variable.

Abstract: A flyback converter to control conduction time in AC/DC conversion technology. The flyback converter includes a primary side and a secondary side. The primary side includes a main switch connecting a primary coil to the input of the flyback converter in series. The secondary side includes a secondary coil coupling with the output terminal of the flyback converter. When a switching frequency of the main switch is at a preset first on time in the range between the off frequency and the second switching frequency, the on-time of the main switch continuously changes corresponding to output load changes. When the switching frequency of the main switch is higher than the first switching frequency, the on time of the main switch is constant. The on time is controlled to change linearly, so as to avoid excessive changes in the output voltage ripples, thereby improving circuit efficiency.

Abstract: An amplifier system may include at least one input source, a flyback converter including a pair of complementary metal oxide silicon field effect transistor (MOSFETs), a controller integrated circuit (IC) having a quasi-resonant (QR) pin and configured to provide a biased drive current to the flyback converter, and a transition component arranged at the controller IC and configured to correct pulse width modulation at the IC to ensure the voltage at a transition pin of the IC is above a predefined threshold during a resonant transition.

Abstract: A method for driving an electronic switch in a power converter and a power converter are disclosed. The method includes: driving an electronic switch (1) coupled to an inductor (2) in the power converter, wherein driving the electronic switch (1) includes driving the electronic switch (1) in a plurality of drive cycles by a drive signal (SDRV), Driving the electronic switch (1) in at least one of the plurality of drive cycles includes: determining a desired duration (TON_DES) of a current (I1) through the switch (1); and adjusting a duration (TDRV) of an on-level of the drive signal (SDRV) dependent on the desired duration (TON_DES) and a delay time (TDEL) obtained in a preceding drive cycle. The delay time (TDEL) is a time duration, in the preceding drive cycle, between a first time instance (t1) when the drive signal (SDRV) changes from the on-level to an off-level and a second time instance (t2) when a current through the electronic switch (1) falls below a predefined threshold.

Abstract: A controller for use with a power converter and a power switch comprising a primary controller and a secondary controller. The primary controller to control the power switch to transfer energy from the input side to the output side of the power converter. The secondary controller to transmit a control signal to the primary controller through a communication link, and to initiate a transition operation with the primary controller through the communication link. The secondary controller comprises a secondary switch control circuit configured to output the control signal in response to an output of the power converter, a charging circuit coupled to an energy storage element for providing power to the secondary control circuit, and a voltage detection circuit coupled to the energy storage element, wherein the voltage detection circuit is configured to indicate to the secondary switch control circuit when to initiate the transition operation.

Abstract: A power supply control device includes a charge circuit charging a capacitor coupled to a second node with a full-wave rectified voltage input into a first node when activated, a first detection circuit detecting if the first node is less than a first voltage, a second detection circuit detecting if the second node is less than a second voltage and if the second node is equal to or higher than a third voltage higher than the second voltage, a discharge circuit discharging an electric charge accumulated in the first node by activation, and a control circuit activating the charge circuit when the voltage of the first node is less than the first voltage, activates the discharge circuit when the second node is less than the second voltage, and deactivates the discharge circuit when the voltage of the second node is equal to or higher than the third voltage.

Abstract: A switch detection circuit is provided that senses the voltage on a rectifying component for rectifying a secondary winding current through a secondary winding of a flyback converter's transformer to determine whether a power switch transistor attached to a primary winding of the transformer has ceased cycling.

Abstract: A controller for use in a power converter includes a secondary controller coupled to receive a feedback signal representative of an output of the power converter to generate d a request signal. A primary controller is coupled to receive the request signal to generate a primary drive signal. The primary drive signal is coupled to control switching of a power switch to control a transfer of energy from the input to the output of the power converter. A frequency to on-time converter included in the primary controller is coupled to receive the request signal. The frequency to on-time converter is coupled to control the duration of on-time pulses included in the primary drive signal in response to a period of the request signal.

Abstract: Example embodiments provide a device that includes a power transformer with a first output voltage terminal providing a first voltage and a second output voltage terminal providing a second voltage, a voltage regulator coupled to one or more of the first output voltage terminal and the second output voltage terminal, and a power storage element that stores power supplied by the second output voltage, and the first output voltage terminal supplies power to a remote entity until a load power requirement of the remote entity exceeds a threshold power level at which time the power storage element is used to provide power from the second output voltage terminal to the remote entity.

Abstract: An active clamp circuit includes an active clamp switch having a drain node and a source node, an active clamp capacitor coupled in a series combination with the active clamp switch, a delay circuit, and an active clamp controller circuit coupled to the active clamp switch and to the delay circuit. The active clamp controller circuit is configured to i) receive an active clamp switch voltage based on a voltage developed across the drain node and the source node of the active clamp switch, ii) enable the active clamp switch based on a voltage amplitude of the active clamp switch voltage, and iii) disable the active clamp switch based on a delay signal generated by the delay circuit.

Abstract: A method may include controlling switching behavior of switches of a switch-mode power supply based on a desired physical quantity associated with the switch-mode power supply, wherein the desired physical quantity is based at least in part on a slope compensation signal and generating the slope compensation signal to have a compensation value of approximately zero at an end of a duty cycle of operation of the switch-mode power supply.

Abstract: A power conversion device includes a transformer, a first electrical switch, a second electrical switch, at least one balanced capacitor, at least one voltage-stabilizing capacitor, and a power-providing circuit. The first electrical switch, the second electrical switch, the balanced capacitor, and the voltage-stabilizing capacitor are connected to the primary side of the transformer, and the secondary side of the transformer is connected to the power-providing circuit. The primary side has a first terminal, a second terminal, and a third terminal therebetween. The first electrical switch and the second electrical switch are respectively connected to a high-voltage terminal and a low-voltage terminal, and the voltage-stabilizing capacitor is connected between the two voltage terminals. One end of the balanced capacitor is connected to the third terminal, and another end of the balanced capacitor is connected to the voltage-stabilizing capacitor or the voltage terminals.

Abstract: A power converter circuit includes a power stage comprising a transformer and a power switch. The power switch can be controlled in response to a PWM signal to provide a primary current through a primary winding of the transformer to induce a secondary current in a secondary winding of the transformer to generate an output voltage. The power stage includes a switching node having a switching voltage between the power switch and the primary winding. A switching controller includes a control transistor device to initiate an operational voltage associated with the control transistor device during a startup mode of the power converter circuit and to provide a control voltage based on an amplitude of the switching voltage during a normal operating mode. The switching controller generates the PWM signal in response to comparing the control voltage and a predetermined switching threshold voltage.

Abstract: The power supply apparatus includes a switching element configured to drive a transformer, a primary side and a secondary side of the transformer being insulated from each other, a control unit configured to output a pulse signal for driving the switching element, and a comparing unit configured to compare a target voltage of an output voltage that is output from the secondary side of the transformer and the output voltage, and to control the output voltage to be the target voltage, wherein the comparing unit cuts off an input of the pulse signal to the switching element in a case where the output voltage is larger than the target voltage, and wherein the control unit determines a frequency or an on-duty ratio of the pulse signal according to the target voltage.

Abstract: Systems and methods for operating light emitting diodes (LEDs) circuits are provided. Aspects include a power supply coupled to the first node, a set of light emitting diodes (LEDs) arranged in series between a second node and a third node, a boost converter coupled to the first node and the second node, a first control circuit configured to operate a first switching element to control operation of the boost convertor, wherein the boost convertor outputs a step-up voltage to drive the set of LEDs, and a second control circuit to operate the second switching element to control operation of the set of LEDs, the second switching element coupled to the third node, wherein the set of LEDs are ON responsive to the second switching element being in an ON state.

Abstract: A power converter includes an input side to receive an input voltage, and an output side to provide an output voltage, a main switch, a controller, a transformer having a primary winding that couples the main switch to the input side, an active clamp switch coupled to the input side by an active clamp capacitor, and an active clamp controller circuit. The active clamp controller circuit includes a sampling circuit to generate a sampled main switch voltage, a delay circuit to generate a delayed sampled main switch voltage, a voltage comparison circuit, and an active clamp switch controller circuit configured to i) enable the active clamp switch based on a first comparison between the sampled main switch voltage and the delayed sampled main switch voltage, and ii) disable the active clamp switch based on a second comparison between the sampled main switch voltage and the delayed sampled main switch voltage.

Abstract: A quasi-resonant auto-tuning controller includes a zero-voltage crossing detection circuit and a valley tuning finite-state machine having a look-up table. The zero-voltage crossing detection circuit receives a reference voltage and receives an auxiliary signal from an auxiliary winding. The zero-voltage crossing detection circuit produces a comparison signal having pulses when the auxiliary signal is less than the reference voltage. The valley tuning finite-state machine produces a divided pulse width based on the comparison signal, stores the divided pulse width of each pulse in the look-up table, determines, from the comparison signal, that the auxiliary signal is less than the reference voltage, waits a time period corresponding to the divided pulse width stored in the look-up table if the auxiliary signal is less than the reference voltage, and produces a valley point signal after waiting the time period.

Abstract: LED backlight circuits for a display and methods for operating the circuits are disclosed. The LED backlight circuit includes a set of drivers and a set of LED strings. A driver can control a light output level of the LED strings. The LED strings can be controlled by a mixed-mode LED driver that utilizes a PWM control signal over a first range of light output levels and an analog control signal over a second range of light output levels. Clock signals used for PWM control and for frequency-to-current or frequency-to-voltage conversion for analog control can both be generated from a phase locked loop (PLL).

Abstract: A power converter includes an input side to receive an input voltage, and an output side to provide an output voltage, a main switch, a controller, a transformer having a primary winding that couples the main switch to the input side, an active clamp switch coupled to the input side by an active clamp capacitor, and an active clamp controller circuit. The active clamp controller circuit includes a sampling circuit to generate a sampled main switch voltage, a delay circuit to generate a delayed sampled main switch voltage, a voltage comparison circuit, and an active clamp switch controller circuit configured to i) enable the active clamp switch based on a first comparison between the sampled main switch voltage and the delayed sampled main switch voltage, and ii) disable the active clamp switch based on a second comparison between the sampled main switch voltage and the delayed sampled main switch voltage.

Abstract: The proposed variant devices are intended for producing a highly stable constant voltage in a wide range of output voltages. A highly stable constant voltage is produced by generating a control signal which adjusts the relative pulse duration as a constant voltage is converted into a pulse voltage, taking into account a constant voltage setpoint value in the load, while also stabilizing a constant current and reducing the pulse components in the constant current through the use of negative feedback.

Abstract: A gate driving circuit includes a first transistor, a first control circuit that changes a gate voltage of the first transistor from a low level to a high level, and a second control circuit that changes the gate voltage of the first transistor from the high level to the low level, wherein the first control circuit and the second control circuit are coupled to each other in parallel with respect to a gate of the first transistor.

Abstract: The invention relates to a constant voltage dimming power supply for lighting device, which is used for adjusting output voltage regulated by dimmer to realize constant voltage PWM output, including a rectifying circuit performing rectifier filtering to output voltage regulated by dimmer; a constant voltage circuit electrically connected to output end of the rectifying circuit; a constant current load circuit electrically connected to output end of the rectifying circuit; a frequency conversion and protection sampling circuit electrically connected to output end of the constant current load circuit and constant voltage; and a switching circuit for controlling lighting load illumination; the frequency conversion and protection sampling circuit converts an output signal of the constant current load circuit into a duty cycle signal suitable for controlling the switching circuit and detects the output abnormality of the constant voltage circuit in real time, and the switching circuit is controlled to be turned on

Abstract: A discrete-time current sense circuit includes: a current mirror circuit, which includes: a power switch, for providing the communication current; and a sampling switch, which is for sampling the communication protocol current in a sampling period in a discrete manner, to generate a sampling current; a bias circuit, for providing a reference voltage to the reference node in the sampling period according to a communication protocol voltage of the communication protocol voltage node; a signal conversion circuit, for generating the discrete-time current sense signal according to the sampling current; and a first switch, for operating to determine the sampling period; wherein the sampling period is part of a complete period in which the power switch provides the communication protocol current.

Abstract: In one general aspect, a control circuit for a power converter can include a feedback terminal configured to be coupled to a non-isolated feedback of the power converter when a feedback of the power converter is the non-isolated feedback, or configured to be coupled to a ground when the feedback of the power converter is an isolated feedback. The control circuit can include a detection circuit, coupled to the feedback terminal. The detection circuit can be configured to trigger a feedback voltage at the feedback terminal within an initial setting of the power converter. The feedback voltage can be high in response to the feedback terminal being coupled to the feedback of the power converter, and the feedback voltage can be low in response to the feedback terminal being coupled to the ground of the power converter.

Abstract: A system for supplying adapted power to an electronic device with a reduced level of power consumption when the device is not in use includes a first power supplying module, a control module coupled to the first power supplying module, and an MCU coupled to the control module and coupled to the electronic device. The MCU is configured to switch on the first power supplying module when the first power supplying module is in normal state, the normal state being an AC power supply coupled to the first power supplying module. The MCU detects an instant mode of the electronic device and outputs a first signal to the control module when the electronic device is in a standby mode. The control module is configured to switch off the first power supplying module when the first signal is received. A power supplying method is further provided.

Abstract: In a calculation method of calculating a switching wave form of an inverter by expressing a wave form obtained by measurement or simulation using a function formula, an intermediate terminal is provided between an upper terminal and a lower terminal of an inverter arm and a power supply of a voltage function formula is provided between the upper terminal and the intermediate terminal or the intermediate terminal and the lower terminal. Further, it may be configured such that a variation impact from peripheral circuits at time of switching is calculated and voltage correction calculation is performed to prevent the calculated switching wave form from changing due to the calculation of the variation impact.

Abstract: A flyback converter with a secondary side control includes a transformer having a primary winding and a secondary winding, a rectifier switching device in the secondary side configured to provide a rectifier path and a switching path, a secondary side control circuit configured to detect the output voltage or current value and to control the states of the rectifier switching device according to the variations between the pre-set voltage or current value and the output voltage or current value, a primary side switching device in the primary side configured to switch between on and off states, an auxiliary winding coupled to the secondary winding for providing power and detecting the states of the secondary side rectifier switching device, and a primary control circuit configured to control the primary side switching device based on the detected output state of the secondary winding from the auxiliary winding.

Abstract: A flyback converter (21) for use in a power supply for an electric actuator system comprises a snubber circuit with a snubber capacitor (23) for accumulating energy stored in a leakage inductance of a flyback transformer (4) when a primary current (Iprim) is switched off. The snubber circuit further comprises a controllable switching element (24) in series with the snubber capacitor (23) with a control terminal connected to a voltage reference. The controllable switching element (24) can be in a conducting mode when the snubber capacitor voltage exceeds the reference voltage. In this way, the leakage inductance energy can be transferred to the secondary side instead of being dissipated in a resistor in the snubber circuit. This increases the power efficiency of the converter and reduces electromagnetic interference. At the same time, the solution is very simple and can thus be implemented at a low cost.

Abstract: Systems and methods are provided for voltage regulation of power conversion systems. An example system controller includes: a first sampling component configured to sample a sensing signal and determine a compensation signal based on at least in part on the sensing signal, the sensing signal being associated with a first current flowing through a primary winding of a power conversion system; a signal processing component configured to receive a feedback signal and the compensation signal and generate a first signal based at least in part on the feedback signal and the compensation signal, the feedback signal being associated with an auxiliary winding coupled with a secondary winding of the power conversion system; an error amplifier configured to receive the first signal and a reference signal and generate an amplified signal based at least in part on the first signal and the reference signal.

Abstract: A primary resonant flyback converter may include a primary winding, a resonant capacitor in series with the primary winding, a secondary winding magnetically coupled to the primary winding, and an output electrically coupled to the secondary winding. A main switch may be operated to energize the primary winding when closed and transfer energy stored in the primary winding to the secondary winding when open. An auxiliary switch may be configured to switch complimentarily to the main switch, thereby allowing a resonant current to circulate through the primary winding and capacitor. Switch timing may be controlled to produce a desired output voltage. The switching frequency may be varied as a function of output load, input voltage and/or voltage ripple on a DC bus of the converter. Switching may also be temporarily disabled responsive to a decrease in output load and re-enabled responsive to an increase in output load.

Abstract: System controller and method for regulating a power converter. For example, the system controller includes a first controller terminal and a second controller terminal. The system controller is configured to: receive, at the first controller terminal, an input signal; generate a drive signal based at least in part on the input signal, the drive signal being associated with an on-time period and an off-time period, the on-time period including a first beginning and a first end; and output, at the second controller terminal, the drive signal to a switch to close the switch during the on-time period and open the switch during the off-time period to affect a current associated with a secondary winding of the power converter. The system controller is further configured to detect a demagnetization period associated with the secondary winding based at least in part on the input signal.

Abstract: A method for regulating a power converter includes initiating a transition of a switch coupled to an input side of the power converter from an OFF to an ON state to regulate a transfer of energy from the input to an output side of the power converter after a switch control signal generator receives an enable signal and if a feedback signal representative of an output of the power converter indicates a change in an output of the power converter. The enable signal is generated to communicate a control signal from the output to the input side in response to a first signal representative of a voltage on an output terminal that oscillates in response to an ending of the transfer of energy. The transition of the switch from the OFF to the ON state occurs substantially at a time that the first signal reaches an extremum.

Abstract: System controller and method for regulating a power converter. For example, the system controller includes a first controller terminal and a second controller terminal. The system controller is configured to: receive, at the first controller terminal, an input signal; generate a drive signal based at least in part on the input signal, the drive signal being associated with an on-time period and an off-time period, the on-time period including a first beginning and a first end; and output, at the second controller terminal, the drive signal to a switch to close the switch during the on-time period and open the switch during the off-time period to affect a current associated with a secondary winding of the power converter. The system controller is further configured to detect a demagnetization period associated with the secondary winding based at least in part on the input signal.

Abstract: A switching power converter is provided that includes a detector to detect whether a controller power supply voltage has fallen below a threshold voltage during a dormant period in which a power switch is no longer cycling to deliver power to a load. In response to a detection of such a threshold crossing by the detector, a controller powered by the controller power supply voltage is configured to cycle the power switch to replenish the controller power supply voltage.

Abstract: The present disclosure provides a common voltage adjustment circuit, a common voltage adjustment method, a display panel and a display device. The common voltage adjustment circuit includes: a filter unit; and a control unit configured to, at a compensation stage, enable a common voltage feedback line to be electrically disconnected from a second input end of a common voltage negative-feedback amplification unit and enable a reference common voltage output end to be electrically connected to the second input end of the common voltage negative-feedback amplification unit through the filter unit, and at a non-compensation stage, enable the common voltage feedback line to be electrically connected to the second input end of the common voltage negative-feedback amplification unit and enable the reference common voltage output end to be electrically disconnected from the second input end of the common voltage negative-feedback amplification unit.

Abstract: A power factor correction circuit corrects a filter current flowing through a filter capacitor asymmetrically based on a peak of an input voltage by controlling a switching operation of a power switch, thereby correcting distortion of an input current.

Abstract: An apparatus for delivering power to a load, which comprises a power converter that converts input power at a primary side to an output power and to a supply voltage to a secondary side. On the secondary side, a load switch is located on a current path to the load. A secondary-side control circuitry controls the load switch to operate in an ON mode in which current is provided to the load, and in response to a fault condition corresponding a voltage drop across the load switch exceeding a threshold value, activates circuitry on the secondary side. The circuitry, in response to the fault condition, causes the primary-side control circuitry to limit an extent to which the power converter is capable of supplying power.

Abstract: A switching power converter may include a power switch coupled to a primary winding of a transformer, and a primary controller configured to turn on and off the power switch, a synchronous rectifier switch coupled to a secondary winding of a transformer, and a synchronous rectifier controller configured to turn on and off the synchronous rectifier switch. The synchronous rectifier controller may monitor a voltage across the synchronous rectifier switch. The synchronous rectifier controller may detect a fault condition responsive to the voltage reaching a turn-off voltage threshold before a minimum on-time timer expires. The synchronous rectifier controller may detect a fault condition responsive to the synchronous rectifier switch being turned off at the same time, immediately after, or within a timing guardband after the minimum on-time timer expires. The synchronous rectifier controller may adaptively increase a minimum off-time period for the synchronous rectifier switch.

Abstract: A switch mode power supply (SMPS) has a primary-side controller configured to control a power switch for turning on and turning off a current flow in the primary winding. A secondary-side controller is coupled to the secondary winding for providing constant voltage (CV) and constant current (CC) control of the SMPS. The secondary-side controller is configured to receive an output selection signal and, based on the output selection signal, select a voltage reference signal from a plurality of voltage reference signals and select a current reference signal from a plurality of current reference signals. The secondary-side controller is configured to monitor an output voltage and an output current of the SMPS, and is configured to provide a turn-on signal to the primary-side controller for turning on the power switch upon determining that the output voltage is below the selected voltage reference signal and the output current is below the selected current reference signal.

Abstract: An apparatus includes logic to determine a discharge drop of a capacitor and to adjust an enablement charge level of the capacitor according to the discharge drop.

Abstract: A switching power converter is provided that extrapolates from a reference voltage during dead periods of a rectified input voltage as determined from a comparison of an Isense voltage to a current threshold.

Abstract: Systems and methods are provided for voltage regulation of power conversion systems. An example system controller includes: a first sampling component configured to sample a sensing signal and determine a compensation signal based on at least in part on the sensing signal, the sensing signal being associated with a first current flowing through a primary winding of a power conversion system; a signal processing component configured to receive a feedback signal and the compensation signal and generate a first signal based at least in part on the feedback signal and the compensation signal, the feedback signal being associated with an auxiliary winding coupled with a secondary winding of the power conversion system; an error amplifier configured to receive the first signal and a reference signal and generate an amplified signal based at least in part on the first signal and the reference signal.

Abstract: In accordance with embodiments of the present disclosure, a switch mode power supply may include a transformer, a controller configured to generate a periodic switching signal, a switching transistor coupled between a sense node and the transformer, primarily configured to prevent or permit current flow in the transformer primary winding in accordance with the switching signal, a sense resistor coupled to the switching transistor at a sense node, and a limit circuit configured to obtain a voltage of the sense node at a particular point of the switching period as an indicator of the primary winding current, detect a duration of a demagnetizing interval, and generate a limit signal, based on the sense node voltage and the demagnetizing interval, indicating a power supply output current exceeding a limit threshold.

Abstract: Systems and methods are provided for voltage regulation of power conversion systems. An example system controller includes: a first sampling component configured to sample a sensing signal and determine a compensation signal based on at least in part on the sensing signal, the sensing signal being associated with a first current flowing through a primary winding of a power conversion system; a signal processing component configured to receive a feedback signal and the compensation signal and generate a first signal based at least in part on the feedback signal and the compensation signal, the feedback signal being associated with an auxiliary winding coupled with a secondary winding of the power conversion system; an error amplifier configured to receive the first signal and a reference signal and generate an amplified signal based at least in part on the first signal and the reference signal.

Abstract: To provide a delay circuit improved in the accuracy of a delay time. A delay circuit is provided which includes a plurality of switches respectively provided between a plurality of constant current sources and a delay time adjustment terminal, a control circuit which ON/OFF-controls the switches, and a comparator circuit which compares a voltage of the delay time adjustment terminal and a reference voltage. The control circuit sequentially turns ON the switches every preset period after a signal is inputted to a signal input terminal and sets as a delay time, a time taken for the comparator circuit to detect that the voltage of the delay time adjustment terminal exceeds the reference voltage.

Abstract: A bipolar junction transistor (BJT) may be used in a power stage DC-to-DC converter, such as a converter in LED-based light bulbs. The power stage may be operated by a controller to maintain a desired current output to the LED load. The controller may operate the power stage by monitoring a start and end of a reverse recovery time of the BJT. Information regarding the start and end of the reverse recovery time may be used in the control of the power stage to improve efficiency of the power stage.

Abstract: When detecting an amount of noise current generated in an inverter and flowing into a noise filter, sampling the detection values with an interval of a carrier frequency, determining whether envelope curves of respective sampled values are deemed to be constant, and in a case where the envelope curves of the sampled values are deemed to be constant, the motor control device changes the carrier frequency to another frequency that does not overlap a cutoff frequency fr of the noise filter, or to another frequency that is not close to the cutoff frequency fr of the noise filter. Due to this configuration, even when the noise filter incorporated in the motor control device is a noise filter that is manufactured without demanding any special measures to be taken to the manufacturers and is manufactured with specifications of noise filter manufacturers, a desired noise reduction effect can be obtained.

Abstract: A power supply device includes a power switch, a power delivering means configured to convert an input in accordance with switching operation of the power switch and output a result, and a switch control circuit configured to linearly control switching frequency of the power switch in accordance with an output detection voltage corresponding to an output voltage according to the output.

Abstract: A switch control circuit that controls a switching operation of a power switch includes: an input current calculator generating an input sense voltage by integrating a sense voltage that indicates a switching current flowing to the power switch for a switching period unit of the power switch; and an input current comparator generating a gate-off signal according to a result of comparison between the input sense voltage and a predetermined input reference voltage, wherein the power switch is turned off according to the gate-off signal.