Abstract: A resonant converter includes an input terminal, an output terminal, a first switch, a second switch, a third switch, a fourth switch, a frequency controller, a resonant capacitor, a first transformer, a second transformer, a feedback circuit and a synchronous rectification controller. The input terminal is connected to an external power supply and the output terminal is connected to an external load. The synchronous rectifier controller is used to output a fourth control signal for controlling the fourth switch based on a voltage at the first terminal of the secondary side of the first transformer, and output a third control signal for controlling the third switch based on a voltage at the second terminal of the secondary side of said second transformer. The present application can effectively reduce the switching losses of the primary side, allowing the resonant converter to operate at a variable high frequency.

Abstract: Method of operating a bidirectional DC DC converter that transfers power among an energy source (for example, a solar PV array), an energy storage system, and an energy usage system (for example, a DC AC inverter) to control the charge and discharge times of the energy storage system so that power harvested during peak energy source production can be stored and can later be released to the energy usage system at predetermined times.

Abstract: In one embodiment, an apparatus includes a power adapter configured for direct connection to a Power Supply Unit (PSU) installed in a network device, the power adapter comprising a power input port for receiving power on an Ethernet cable, a power converter module for converting the power received at the power input port to a PSU input power, and a power output connector for connection with a PSU power input connector.

Abstract: A bidirectional DC DC converter that transfers power among an energy source (for example, a solar PV array), an energy storage system, and an energy usage system (for example, a DC AC inverter). The converter controls the charge and discharge times of the energy storage system so that power harvested during daylight can be metered to the DC AC inverter at predetermined times. During charge times, the converter utilizes synchronous rectification when down-converting higher voltages to lower voltages and during discharge times the converter utilizes variable overlapping of switch drive signals to provide a continuous range of voltage levels of transferred power from the energy storage system to the DC AC inverter.

Abstract: A half bridge switching cell includes two primary switching elements and a transformer with primary and secondary windings. Synchronized rectifiers correspond to the primary switching elements such that each of the synchronized rectifiers conducts when the corresponding primary switching element is not conducting. Each secondary winding is connected to one of the synchronous rectifiers and to a common connection and controlled current source. The primary switching elements conduct during offset times separated by a dead time. A magnetizing current flows through the secondary windings and synchronous rectifiers during the dead time. The magnetizing current flows into the primary winding when each of the synchronous rectifiers is turned off after the dead time, discharging a parasitic capacitance across the one of the primary switching elements when the corresponding synchronous rectifier is turned off, thereby creating a zero voltage switching condition at turn on for the primary switching elements.

Abstract: An input voltage control device including a first power line inputted with a voltage of 300V to 380V and a second power line inputted with a voltage of 0V. The potential difference between the first power line and the second power line is variable. A constant voltage generator outputs a constant potential voltage of (24V, for example) to a third power line. A reference potential generator outputs a reference potential of (10V, for example). A comparative potential generator outputs a comparative potential which is within the range of (0V to 24V, for example), based on the input voltage. A comparator outputs to an NMOS transistor a conducting potential voltage of (24V, for example) or an interrupting potential voltage of (0V, for example) depending on the comparison between the reference potential and the comparative potential. When the comparator outputs the conducting potential, the path between the source and drain of the NMOS transistor is made conductive.

Abstract: The present invention provides a multi-load control apparatus, a slave circuit and a control method thereof. The multi-load control apparatus includes a master circuit and at least one slave circuit. The master circuit generates at least one pulse width modulation (PWM) signal according to an input signal. The slave circuit controls a power switch according to a corresponding PWM signal. The slave circuit has a primary side circuit and a secondary side circuit. The primary side circuit generates an AC PWM signal according to the corresponding PWM signal. The power switch has a control terminal which is driven according to a floating ground level which is not a constant voltage level. The power switch has a current inflow terminal and a current outflow terminal, which are connected to a corresponding load circuit in series, wherein the series circuit of the power switch and the load circuit receives an AC voltage.

Abstract: The present invention provides a switching power supply and a controller thereof, wherein the controller comprises: a switching power supply control device having a power supply terminal and detecting a voltage at the power supply terminal; a composite device integrating therein a power transistor and a depletion transistor, wherein the power transistor has a gate coupled to a first input, a source coupled to a first output, and a drain coupled to an input signal terminal; the depletion transistor has a gate coupled to a second input, a source coupled to a second output, and a drain coupled to the input signal terminal; the first input, the second input and the second output are coupled to the switching power supply control device, the first input receives a driving signal generated by the switching power supply control device, and the input signal terminal receives an input signal of the switching power supply.

Abstract: To provide a receiver, a communication device, and a communication method capable of restoring a signal transmitted via a non-contact transmission channel with high accuracy. A communication device has a transmission circuit that converts an input signal into a pulse, a non-contact transmission channel that has a primary side coil and a secondary side coil and transmits the pulse from the transmission circuit in a non-contact manner, a restoration circuit that restores the input signal on the basis of a reception signal corresponding to the pulse transmitted via the non-contact transmission channel, an initialization unit that initializes an output of the non-contact transmission channel, and an initialization control unit that outputs a control signal of controlling the initialization unit on the basis of the reception signal corresponding to the pulse received via the non-contact transmission channel.

Abstract: In one embodiment, an undervoltage protection circuit for a switching power supply can include: (i) an undervoltage detection circuit that determines whether an input voltage of the switching power supply is in an undervoltage state; (ii) a selection circuit configured to select a first or a second control signal to be provided as a main control signal to a control circuit; (iii) the control circuit being configured, in response to the main control signal being the first control signal, to control a switching operation of a power transistor in the switching power supply such that an output voltage of the switching power supply is maintained as substantially stable; and (iv) the control circuit being configured, in response to the main control signal being the second control signal, to control the switching operation of the power transistor to reduce an input power of the switching power supply.

Abstract: Disclosed are systems, devices, apparatus, circuits, methods, and other implementations, including a system that includes one or more power switching devices that receive power delivered by a power unit, and a high-speed charge control circuit electrically coupled to the one or more power switching devices. The high-speed charge control circuit includes an optocoupler coupled to the power unit and further coupled to a first switching device of the high-speed charge control circuit, the first switching device actuated based on output of the optocoupler to establish an electrical path to discharge at least a portion of electrical charge present at least on the one or more power switching devices when power delivery from the power unit is stopped.

Abstract: A power converter having a clock module and a method for controlling a clock signal of the power converter. The clock module is configured to provide the clock signal and to set a clock frequency of the clock signal to a first predetermined frequency at the moment when the power converter is powered on. The clock module is further configured to regulate the clock frequency to increase from the first predetermined frequency to a second predetermined frequency through a predetermined times of step type frequency increase during a startup procedure of the power converter.

Abstract: A knee voltage detector for a flyback converter is provided. The knee voltage detector comprises a delay unit, for delaying an auxiliary related voltage for a specific period, to generate a delay signal; a subtracting unit, for generating a subtraction signal according to the auxiliary related voltage and the delay signal; a comparing unit, for generating a sampling signal when the subtraction signal indicates that a voltage difference between the auxiliary related voltage and the delay signal is greater than a threshold; and a sample and hold unit, for sampling the delay signal to generate a knee voltage according to the sampling signal when the voltage difference between the auxiliary related voltage and the delay signal is greater than the threshold.

Abstract: In one embodiment, a method of compensating for transmission voltage loss from a switching power supply, can include: (i) receiving a sampling signal that represents an output current of the switching power supply; (ii) delaying the sampling signal to generate a delayed sampling signal; (iii) converting the delayed sampling signal to generate a compensation signal; and (iv) regulating an output voltage of the switching power supply based on the compensation signal to compensate for the transmission voltage loss from the output voltage transmission to a load such that a voltage at the load is maintained as substantially consistent with an expected voltage at the load.

Abstract: A switch-mode power supply includes a converter, a controller and a charging current. The charging current includes a logic circuit, a first current source and a second current source, to generate a charging current proportional to an input voltage of the switch-mode power supply, and also to generate a logic control signal indicative of either of two operation modes.

Abstract: A power distribution system includes controller of a switching power converter to control the switching power converter and determine one or more switching power converter control parameters. In at least one embodiment, the controller determines the one or more switching power converter control parameters using a resonant period factor from a reflected secondary-side voltage and an occurrence of an approximate zero voltage crossing of the secondary-side voltage during a resonant period of the secondary-side voltage. In at least one embodiment, the switching power converter control parameters include (i) an estimated time of a minimum value of the secondary-side voltage during the resonant period and (ii) an estimated time at which a current in the secondary-side of the transformer decayed to approximately zero.

Abstract: A power conversion circuit includes a voltage boost circuit configured to generate an output voltage in response to an input voltage, a boost controller configured to control operation of the voltage boost circuit, and a bias voltage generation circuit configured to generate a bias voltage. The bias generation circuit is configured to regulate a level of the bias voltage in response to a level of the input voltage.

Abstract: A switching regulator configured to convert an input voltage input to an input terminal into a predetermined constant voltage by switching with at least two elements including a pair of switching elements or a switching element and a rectifying element, and output the converted voltage as an output voltage from an output terminal includes a comparison unit configured to compare a signal showing an oscillating frequency of the switching regulator with a signal showing a constant frequency, and a driver configured to delay a pulse signal generated by feeding-back a control signal and an output signal of the switching regulator according to the comparison result by the comparison unit with a predetermined time, and switch the input voltage by using the at least two elements based on the pulse signal after the delay.

Abstract: Aspects of the disclosure provide a method that including receiving a sensed signal corresponding to a current flowing through an energy transfer module in response to an on/off state of a forward-type triode for alternating current (TRIAC), determining the TRIAC on/off state based on the sensed signal, and controlling the energy transfer module based on the determined TRIAC on/off state.

Abstract: Disclosed is a method for controlling a permanent magnet synchronous motor to maximize use of voltages of a battery by voltage phase control within weak magnetic flux area and to achieve compensation for a torque error through a torque compensator when driving the permanent magnet synchronous motor for hybrid vehicles. In particular, the method controls a permanent magnet synchronous motor so that voltage use can be maximized in a weak magnetic flux area by using voltage near maximum voltage through voltage phase control utilizing magnetic flux-based map data receiving a torque command and motor speed/batter output voltage as inputs and torque error can be compensated using a torque compensation filter when a motor constant is changed in the weak magnetic flux by a circumstance parameter, when the permanent magnet synchronous motor mounted in a hybrid vehicle and an electric vehicle is driven.

Abstract: A bi-directional DC/DC converter includes at least one module having a module input for providing a bi-directional module input current, and a module output with an output inductor for providing a bi-directional module output current. A transformer has a primary winding wound around a transformer core and connected to the module input, and a secondary winding wound around the core and connected to the module output. A primary set of switches is connected in an H-bridge configuration between the module input and the primary winding. And, a secondary set of switches is connected in an H-bridge configuration between the module output and the secondary winding. A current sensing component senses the module output current. A hysteretic control drives the primary set of switches to control flux. The hysteretic control drives the secondary set of switches to control the module output current as a function of the sensed module output current.

Abstract: System and method for regulating a power converter. The system includes a comparator configured to receive a first signal and a second signal and generate a comparison signal based on at least information associated with the first signal and the second signal. The first signal is associated with at least an output current of a power converter. Additionally, the system includes a pulse-width-modulation generator configured to receive at least the comparison signal and generate a modulation signal based on at least information associated with the comparison signal, and a driver component configured to receive the modulation signal and output a drive signal to a switch to adjust a primary current flowing through a primary winding of the power converter. The modulation signal is associated with a modulation frequency corresponding to a modulation period.

Abstract: Some implementations are directed to a A DC-to-DC converter that includes a power transformer having a primary side and a secondary side and a plurality of power transistors coupled to the primary side of the transformer. The converter also includes a secondary bias supply coupled to the secondary side of the transformer and a secondary side controller coupled to the secondary side of the transformer and configured to generate a feedback control signal based on a voltage level associated with the secondary side of the transformer. The the secondary side controller receives operating power only from the secondary bias supply.

Abstract: The frequency characteristic of a voltage-feedback class-D amplifier circuit for driving an output load is improved. A triangular-wave correction circuit which compensates a gradient of a triangular wave is provided to a triangular-wave signal generator which supplies a triangular wave signal used as a PWM carrier to a comparison circuit for performing PWM modulation of an input signal. In an area where a duty of a command value for an output circuit drive becomes about 50%, a slew rate (gradient) of the triangular wave is decreased.

Abstract: Provided is a drive device for an alternating current motor which performs vector control on sensorless driving of the alternating current motor in an extremely low speed region without applying a harmonic voltage intentionally while maintaining an ideal PWM waveform. A current and a current change rate of the alternating current motor are detected, and a magnetic flux position inside of the alternating current motor is estimated and calculated in consideration of an output voltage of an inverter which causes this current change. The current change rate is generated on the basis of a pulse waveform of the inverter, and hence the magnetic flux position inside of the alternating current motor can be estimated and calculated without applying a harmonic wave intentionally.

Abstract: A synchronous rectifier for a switching power converter is provided and includes a power transistor, a diode, and a control circuit. The power transistor and the diode are coupled to a transformer and an output of the power converter for the rectification. The control circuit generates a drive signal to switch on the power transistor once the diode is forward biased. The control circuit includes a phase-lock circuit. The phase-lock circuit generates an off signal to switch off the power transistor in response to a pulse width of the drive signal. The pulse width of the drive signal is shorter than a turned-on period of the diode. The phase-lock circuit further reduces the pulse width of the drive signal in response to a feedback signal. The feedback signal is correlated to an output load of the power converter.

Abstract: The PWM control circuit is provided. The PWM control circuit includes: a PWM control signal generator that generates a PWM period signal defining a period of a PWM signal and a PWM resolution signal specifying a resolution in one period of the PWM period signal; and a PWM unit that generates the PWM signal based on the PWM period signal and the PWM resolution signal, wherein the PWM control signal generator changes a frequency of the PWM resolution signal while keeping a frequency of the PWM period signal unchanged.

Abstract: Embodiments of the invention relate generally to power management and the like, and more particularly, to an apparatus, a system, a method, and a computer-readable medium for providing power controlling functionality to generate configurable power signals and to deliver power during fault conditions. In at least some embodiments, a power control unit can generate power signals having configurable attributes as a function of a mode of operation, a fault type, and the like.

Abstract: The present invention relates to an oscillator that is capable of realizing duty balancing. The oscillator determines a switching frequency of a converter converting an input voltage according to a switching operation of switches to generate an output voltage. The oscillator determines a first half cycle of a duty signal determining the switching frequency by using a reference current according to a feedback signal corresponding to the output voltage. The oscillator senses a first half cycle period by using an output of the frequency setting unit, and determines the same period as the first half cycle as a second half cycle of the duty signal after the first half cycle.

Abstract: Embodiments of the invention relate generally to power management and the like, and more particularly, to an apparatus, a system, a method, and a computer-readable medium for providing power controlling functionality to generate configurable power signals and to deliver power during fault conditions. In at least some embodiments, a power control unit can generate power signals having configurable attributes as a function of a mode of operation, a fault type, and the like.

Abstract: A control circuit selectively energizes a load, such as an elevator or escalator brake (12). The circuit includes a transformer (28) with a primary-winding connected to a series with a semiconductor switch (40) that is driven by a pulse width modulation (PWM) controller. Power to the PWM controller is supplied through safety relay contacts (52A, 52B). When the load is to be energized, the safety relay contacts are closed and the PWM controller drives the semiconductor switch to supply energy through the transformer to the secondary circuit. A command signal to secondary circuitry (64) causes power in the secondary to be applied to the load (12). If the safety relay contacts open, the PWM controller turns off and power is no longer delivered to the secondary circuit and the load.

Abstract: A power supply unit includes a switching power converter responsive to a control signal to switch a power switch thereof to provide an output voltage and an output current for a load. To reduce light-load or no-load power consumption of the power supply unit, the power supply unit repeats a process of stopping switching the power switch and recovering switching the power switch for a period of time once the output voltage decreases to be lower than a reference voltage.

Abstract: An example controller for use in a power supply regulator includes a switch signal generator, a modulation circuit, and a multi-cycle modulator circuit. The modulation circuit modulates the period of a modulation switching signal when an equivalent switching frequency is greater than a reference frequency and fixes the switching period when the equivalent switching frequency is less than the reference frequency. The multi-cycle modulator circuit enables the switch signal generator to provide a switch signal uninterrupted if the equivalent switching frequency is greater than the reference frequency and disables the switch signal generator for a first time period and then enables the switch signal generator for a second time period when the equivalent frequency is less than the reference frequency. The multi-cycle modulator circuit varies the first time period to regulate the output.

Abstract: Extending pulse width modulation phase offset when generating phase shifted groups of pulse width modulation (PWM) signals is accomplished with a separate phase counter that is independent of the time-base counters used in traditional PWM generation circuits and that is prevented from being retriggered until an existing duty cycle has completed. This is accomplished with a phase offset counter, a phase comparator and a circuit that is triggered via a master time base for overall synchronization of the multi-phase PWM signal generation.

Abstract: With the use of a voltage across a secondary winding of a transformer, a DC output voltage and a conduction time width of a current in the DC reactor on the secondary side circuit in an immediately preceding period, the turning-on time width and the turning-off time width of a synchronous rectification MOSFET in the secondary side circuit of the transformer are obtained by calculations, without receiving any signals from a primary side circuit, to thereby carry out control of a synchronous rectification circuit in a forward DC-DC converter with the time in which a current flows in a diode reduced to the minimum.

Abstract: A switching power controller circuit comprises a first terminal pin for a high potential of a power supply for the controller circuit, a second terminal pin for providing output of switch drive signals and for receiving feedback signals, and a third terminal pin for receiving external current signals and for a low potential of the power supply. The switching power controller further comprises a clock generator, a pulse width modulation (PWM) generator, a reference generator, a power switch driver, a feedback signal sampler, a PWM comparator and a floating sampler.

Abstract: Novel system and methodology are provided for controlling a DC/DC forward converter having a transformer with primary and secondary windings, a reset switch, and a first switch coupled to the primary winding of the transformer. The control system involves a PWM control circuit responsive to an output signal of the converter for producing a PWM signal to control switching of the reset switch, and the first switch. A period of the PWM signal includes an on-time interval for enabling transfer of power via the transformer when the first switch is on, and a reset time interval for enabling reset of the transformer when the reset switch is on. A maximum value of the on-time interval is pre-set to provide sufficient time for the reset. The reset switch is turned off when the PWM signal goes from a first level to a second level. A first delay period is set between time when the reset switch turns off and time when the first switch turns on.

Abstract: In order to convert an input power to one or more DC power levels that are provided to an output load, some aspects of the present disclosure relate to techniques for driving a switching regulator as a function of a pulsed voltage signal. In particular, this pulsed voltage signal is provided substantially at a target frequency, but exhibits frequency jitter that causes the pulsed voltage to vary slightly from the target frequency in time. The frequency jitter has a frequency range that varies as a function of the output load.

Abstract: The PWM control circuit is provided. The PWM control circuit includes: a PWM control signal generator that generates a PWM period signal defining a period of a PWM signal and a PWM resolution signal specifying a resolution in one period of the PWM period signal; and a PWM unit that generates the PWM signal based on the PWM period signal and the PWM resolution signal, wherein the PWM control signal generator changes a frequency of the PWM resolution signal while keeping a frequency of the PWM period signal unchanged.

Abstract: A power converter in one aspect limits the magnetic flux in a transformer. A control circuit included in the power converter includes a pulse width modulator, a logic circuit and a saturation prevention circuit. The saturation prevention circuit asserts a first signal when a first integral value of the input voltage reaches a first threshold value and asserts a second signal after a delay time that begins when a difference between the first integral value and a second integral value of a reset voltage of the transformer falls to a second threshold value. The logic circuit turns off the switch when the first signal is asserted, and allows the switch to turn on and off in accordance with the pulse width modulator when the second signal is asserted.

Abstract: An example controller for use in a power supply regulator includes a switch signal generator, a modulation circuit, and a multi-cycle modulator circuit. The modulation circuit modulates the duty cycle of a pulse width modulated switching signal to provide a fixed peak switching current in the switch during light load conditions and a variable peak switching current during load conditions other than the light load condition. The multi-cycle modulator circuit enables the switch signal generator to provide a switch signal uninterrupted if the load condition is other than the light load condition and disables the switch signal generator for a first time period and then enables the switch signal generator for a second time period when the load condition is the light load condition. The multi-cycle modulator circuit adjusts the first time period in response to the feedback signal to regulate the output.

Abstract: The frequency characteristic of a voltage-feedback class-D amplifier circuit for driving an output load is improved. A triangular-wave correction circuit which compensates a gradient of a triangular wave is provided to a triangular-wave signal generator which supplies a triangular wave signal used as a PWM carrier to a comparison circuit for performing PWM modulation of an input signal. In an area where a duty of a command value for an output circuit drive becomes about 50%, a slew rate (gradient) of the triangular wave is decreased.

Abstract: A slope compensation method and circuit for a peak current control mode power converter circuit is provided. Since the power converter circuit has a synchronous signal of a driven signal of enabling the first primary switch and the second primary switch, a triangular wave signal is generated. The driven signals of the first and second primary switches determine the ramp up time of the triangular wave signal. The triangular wave signal is added to one of the output DC voltage feedback signal of the corresponding power converter circuit that are used to compare with a current peak value of the voltage feedback signals. Therefore, a high level triangular wave DC voltage feedback signal that is higher than the DC voltage feedback signal is formed, and the switching noises do not effect comparing result of a PWM controller of the power converter circuit.

Abstract: A driver for driving a driving element includes: a signal source, for providing a square signal; a first modulation circuit, for providing on-pulses and off-pulses according to edges of the square signal; a transformer for coupling output signals of the first modulation circuit to a secondary winding of the transformer to form coupled signals; a second modulation circuit for providing first operating pulses according to coupled on-pulses of the coupled signals, and providing second operating pulses according to coupled off-pulses of the coupled signals; a switch device for turning off the switch device according to the first operating pulses and turning on the switch device according to the second operating pulses, and when the switch device is turned off, coupled on-pulses charge an equivalent capacitor of the driving element to a first driving potential to turn on the driving element, and when the switch device is turned off, the equivalent capacitor discharges to a second driving potential to turn off the

Abstract: Embodiments of the invention relate generally to power management and the like, and more particularly, to an apparatus, a system, a method, and a computer-readable medium for providing power controlling functionality to generate configurable power signals and to deliver power during fault conditions. In at least some embodiments, a power control unit can generate power signals having configurable attributes as a function of a mode of operation, a fault type, and the like.

Abstract: A practical method and system for oversampled digitally controlled DC-DC converters is presented. To minimize the switching losses while maintaining all advantages of the oversampling, “glue logic” and application specific oversampling digital pulse-width modulator are introduced. Experimental results demonstrate transient response with 50% smaller deviation than that of conventional controllers, allowing for proportional reduction in the size of the power stage output capacitor.

Abstract: A power supply system allowing remote adjustments of the power output of the power supply unit without having to physically access the power supply unit itself is disclosed. A power supply system in accordance with the present invention utilizes a central processing unit (CPU) to provide a command that adjusts to the power output via a modified pulse width modulator (MPWM). Moreover, the central processing unit (CPU) may also be used to provide fine tune adjustments to the error signal of the power supply system, wherein the central processing unit (CPU) produces a command for the modified pulse width modulator to control the power output.

Abstract: A high-voltage discharge lamp lighting device provides a starting pulse voltage sufficient to turn on a high-voltage discharge lamp having terminal wire connections of variable length. A power conversion circuit is coupled to a commercial AC power source input and rectifies the AC input into a predetermined DC voltage output. A charging capacitor is coupled to the power conversion circuit. A full bridge circuit is coupled to the power conversion circuit and the charging capacitor and provides a rectangular wave AC output signal to a transformer primary winding circuit of at least a capacitor, a single switching element and a primary winding of a transformer. A low pulse voltage is induced in the primary winding and a transformer secondary winding is connected on one end to the high-voltage discharge lamp, wherein the low pulse voltage is stepped up to a high pulse voltage and applied to the high-voltage discharge lamp.

Abstract: Circuitry includes an acquiring circuit to acquire period and phase information of an oscillation. The acquiring circuit includes a first input electrically coupled to a first connection and a second input electrically coupled to a second connection. The first connection and the second connection are for electrically coupling to an oscillating circuit. A control circuit includes a first input electrically coupled to an output of the acquiring circuit. The control circuit includes a second input electrically coupled to a third connection for supply of a voltage that is based on the rectified voltage. A switch includes a controlled segment for electrically coupling a fourth connection to a reference potential connection, and a control connection that is electrically coupled to an output of the control circuit to excite an oscillation in the oscillating circuit via a DC voltage.

Abstract: A resonant switching power converter having burst mode transitioning operates during low or zero load conditions with reduced audible noise and component stresses, while improving efficiency. Pulse bursts are generated with a beginning and/or ending pulse duration that differs from mid-burst pulse durations, in order to reduce an amplitude of transients otherwise generated at the beginning and/or end of the bursts. Alternatively, the spacing between the pulses at the beginning and/or end of the bursts may differ from the spacing between the pulses in the middle of the bursts to reduce the transient(s). A number of pulses at the beginning and/or end of the burst can also be set with gradually varying durations, to further reduce component stress and audible vibration in a transformer that couples the resonant tank to the output of the converter.