Abstract: A resonant conversion system is provided, in which a resonant converter receives an input voltage to generate an output voltage, and a buck converter provides the input voltage of the resonant converter, and controls the input voltage to perform an over-current protection process.

Abstract: Disclosed is flyback converter having a controller that performs a startup switching process when the flyback converter is powered up, and then performs normal switching afterward. The controller includes a pulse generator to generate a control signal for normal switching. During startup switching, the controller may generate a control signal by output every Nth pulse from the pulse generator. In another embodiment, the controller may generate pulses based on a sense signal provided from an input section of the flyback converter.

Abstract: A system for supplying an electrical system with direct current, the system including at least two direct current power supply devices each having means of electrical connection to an alternating current power supply source and an AC/DC converter of alternating current into direct current, a module for managing the power supply of the electrical system which, after reception of an information of failure of a first active power supply device, transmits a command to start up a second inactive power supply device and a back up electrical energy storage device electrically by-pass connected between the power supply devices and the electrical system. The management module also receives the information of failure from the back up device and/or from the electrical system and transmits the command to start up the second power supply device during a discharge phase of the back up device.

Abstract: For a more stable start-up procedure, a switch mode power converter has at least one inductive component including an output inductor L1 and a synchronous rectification element, said power converter comprising a control device and being characterized in that the control device is arranged, at startup of the power converter, to determine a duty-cycle of the control signal, including a normal pulse width of the control pulse, and provide an initial control signal to the at least one switch element that is designed to balance the current in the at least one inductive component of the converter. The initial control signal preferably has a duration of 50% of the normal pulse width.

Abstract: A start-up circuit with low standby power loss for power converters according to present invention comprises a first diode and a second diode coupled to an input voltage of the power converter. A start-up resistor is coupled to the join of the first diode and the second diode. A high-voltage switch is coupled to the start-up resistor to generate a power source. A control circuit generates a switching signal for switching a transformer. A detection circuit generates a disable signal in response to the input voltage to disable the switching signal. A winding of the transformer is coupled to the power source to generate the power for the power source. The high-voltage switch is turned off to cut off the start-up resistor for saving the power loss once the voltage of the power source is higher than a threshold.

Abstract: The present invention relates to a switch control device, a power supply device, and a switch control method. A switch control device controls a switching operation of a power switch by using a feedback voltage of an output voltage. In detail, the switch control device generates the feedback current according to the feedback voltage and the feedback signal corresponding to the feedback voltage by using the feedback current. The switch control device compares the sensing signal corresponding to the drain current flowing to the power switch and the feedback signal, and turns off the power switch according to the comparison result. The switch control device increases the feedback gain rather than the feedback current during the gain compensation period after a predetermined gain compensation period, and the gain compensation period is longer than a soft start period in which the output voltage is gradually increased.

Abstract: A gate driver of a switching element includes a first capacitor having a first end connected to a DC power source, a first switch having a first electrode connected to the first end of the first capacitor and a second electrode connected to a negative electrode of the DC power source, a second switch having a third electrode connected to the second electrode and the negative electrode of the DC power source and a fourth electrode connected to the first capacitor, a second capacitor connected in parallel with the third and fourth electrodes of the second switch and having a first end connected to the DC power source, and a negative voltage controller connecting the gate of the switching element to the second end of the first capacitor and a second end of the second capacitor when the switching element is turned off.

Abstract: A power system and a starting method thereof includes a power output circuit, a loop circuit, a soft start circuit, and a constant-current source that supplies power to the soft start circuit. The loop circuit includes a loop circuit capacitor. The power system further includes a precharge circuit that charges the loop circuit capacitor, and the precharge circuit charges the loop circuit capacitor when the soft start circuit charges the power output circuit.

Abstract: A semiconductor device incorporates a resistor on a structure that uses diffusion layers for sustaining the breakdown voltage thereof to realizes a very resistive element that exhibits a high breakdown voltage and high electrical resistance, includes a spiral very resistive element buried in an interlayer insulator film. A first end of the very resistive element is connected to a drain electrode wiring and the second end of the very resistive element is grounded. An intermediate point of the very resistive element is connected to ae voltage comparator of a control IC. The semiconductor device according to the invention facilitates reducing the components parts costs, assembly costs and size of a switching power supply that includes a very resistive element.

Abstract: A regulating apparatus with soft-start and fast-shutdown function is applied to a voltage-supplying apparatus. The regulating apparatus includes a soft-start and fast-shutdown circuit, a regulating circuit, and a ground circuit. When voltages are supplied from the voltage-supplying apparatus to the soft-start and fast-shutdown circuit, the regulating circuit, and the ground circuit, the ground circuit is connected to ground, so that the starting time of the regulating circuit is delayed by the soft-start and fast-shutdown circuit. When voltages are not supplied from the voltage-supplying apparatus to the soft-start and fast-shutdown circuit, the regulating circuit, and the ground circuit, the ground circuit is not connected to ground, so that the regulating circuit is shut down fast by the soft-start and fast-shutdown circuit.

Abstract: Disclosed are a switch controller, a switch control method, a converter using the same, and a driving method thereof. A first voltage is generated by using a voltage that is input to an input terminal, and a soft start signal is generated by using the first voltage during a soft start duration. A switching operation is controlled by using the soft start signal during the soft start duration.

Abstract: An isolated DC-DC converter includes a transformer, a main switch, an active clamp circuit and a control unit. The transformer has a primary winding. The main switch and the active clamp circuit are connected to the primary winding. The active clamp circuit has an auxiliary switch and a clamp capacitor connected in series. The control unit is provided for controlling the main switch and the auxiliary switch. The control unit performs a soft start operation of the converter before a normal operation. The control unit performs anti-saturation control before starting the soft start operation. The anti-saturation control includes an act of controlling the main switch and the auxiliary switch so that the auxiliary switch performs ON-OFF operation with the main switch kept OFF until voltage of the clamp capacitor drops below a level at which the transformer is to be magnetically saturated after starting the soft start operation.

Abstract: An active damping switching system can include an active damper apparatus having a stabilization resistor, a stabilization switch coupled to the stabilization resistor, an active damper controller coupled to the stabilization switch, a current sensor coupled to the active damper controller. The system can further include a direct current power source coupled to the active damper apparatus, a constant power load and an input filter disposed between the constant power load and the active damper apparatus.

Abstract: An AC-DC power converter includes a rectifying unit for generating a rectified voltage, an output stage for converting the rectified voltage into a DC voltage for a load, a controller for controlling the output stage, and a start-up circuit. The start-up circuit includes a first power section coupled to the rectifying unit and configured to generate a first voltage from the rectified voltage and to output the first voltage to the controller to enable the controller before the output stage starts outputting power. The first power section includes a depletion mode transistor having a first terminal configured to receive the rectified voltage and a second terminal configured to output the first voltage.

Abstract: A power supply apparatus includes a power supply circuit and a power-on circuit. The power-on circuit detects a remotely transmitted control signal and causes a transition of the power supply circuit to a turned on state. The power-on circuit includes a transducer configured to provide a power-on signal in response to the remote control signal. The transducer triggers transition to the turned on state through a switch driven by the power-on signal output from the transducer and arranged to supply a power supply circuit enable signal. A DC blocking capacitor is connected between an output of the transducer and a control terminal of the switch.

Abstract: A DC-DC converter transforms a DC input voltage to generate a DC output voltage by complementary switching control of a main switching transistor and a synchronous rectifying transistor. The DC-DC converter includes a soft-start circuit configured to generate a soft-start voltage rising from an initial voltage at start-up of the DC-DC converter; and a control circuit configured to control switching of the main switching transistor and the synchronous rectifying transistor based on the soft-start voltage to perform soft start of the DC-DC converter. The control circuit brings both of the main switching transistor and the synchronous rectifying transistor to an off state while the soft-start voltage is lower than the DC output voltage.

Abstract: A control device for a switching device with separate start-up and holding coils includes control electronics to control the current supply to the start-up and holding coils and a direct voltage supply unit for the holding coil and the control electronics with the same reference potential for the holding coil and the control electronics.

Abstract: In one embodiment, a startup circuit for a power supply is provided. The startup circuit comprises a resistance coupled between a voltage source and a first node. A first capacitor, coupled to the first node, is operable to be charged by current flowing through the resistance. A first transistor has an emitter, a base, and collector, wherein the collector is coupled to the voltage source and the base is coupled to the first node. A diac circuit, coupled to the emitter of the first transistor, is operable to fire to turn on the first transistor, thereby allowing discharge of the first capacitor through the base-emitter junction of the first transistor. A second capacitor is operable to be charged by current related to a discharge voltage resulting from the firing of the diac circuit. The second capacitor operable to store charge to provide VCC voltage to a controller of the power supply.

Abstract: A power converter controller is disclosed. An example controller includes a control circuit coupled to receive a feedback signal representative of an output of the power converter. The control circuit coupled to control a switching of a power switch of the power converter in response to the feedback signal to control a transfer of energy from an input of the power converter to the output of the power converter. An internal programming interface circuit is coupled to the control circuit. A coupling switcher is coupled to the internal programming interface circuit. An external programming terminal is selectively coupled to the internal programming interface circuit through the coupling switcher. An external programming circuit coupled to the external programming terminal is coupled to the internal programming interface circuit through the coupling switcher during a startup programming condition and during a fault condition of the power converter.

Abstract: Improving start-up time of a light emitting diode (led) driver at lower input voltage is accomplished with a quick start circuit comprising a constant current source that replaces the traditional trickle charge start-up path for charging of a Vcc capacitor supplying operating voltage to an SMPS controller. Also the constant current source will only be operational during SMPS start-up, then will turn off after the SMPS is capable of producing its own regulated power supply to the Vcc terminal of the SMPS controller, thereby minimizing E2/R power losses in the SMPS.

Abstract: The present invention provides an isolated switch-mode power supply device capable of sufficiently reducing power consumption in a standby mode. An isolated switch-mode power supply device includes: a capacitor that supplies control power for controlling switching of a switching element; a first control unit that includes a constant current supplying unit that controls switching of the switching element; a switching element that connects or disconnects the first control unit and the capacitor; a capacitance element unit having a capacitor to which a constant current is supplied from the constant current supplying unit, a capacitor charge voltage of the capacitance element unit changing according to an outputted voltage in the standby mode; and a second control unit that controls power supply to the first control unit by closing or opening the switching element during a switching pause period in the standby mode according to the capacitor charge voltage of the capacitor.

Abstract: A voltage source inverter comprises a rectifier having an input for connection to a multi-phase AC power source and converting the AC power to DC power at an output. An inverter receives DC power and converts the DC power to AC power. A DC bus is connected between the rectifier circuit and the inverter circuit to provide a relatively fixed DC voltage for the inverter. A bus capacitor is across the DC bus. A soft charge circuit limits inrush current to the bus capacitor. The soft charge circuit comprises an input inductor for each phase connected between the rectifier input and the AC power source and a clamping circuit across each input inductor to limit DC bus voltage.

Abstract: A power inverter system includes a plurality of power semiconductor switching devices. Each switching device includes a corresponding gate turn off resistance configured to increase during starting up periods of the inverter system such that the open circuit voltage of a corresponding power source providing power to the power inverter system does not exceed the switching device blocking voltage ratings during the corresponding switching turn-off periods. The starting up period is the time required to bring the corresponding power source voltage from its open circuit voltage level to a predetermined voltage which constitutes a safe operating condition for the plurality of power semiconductor switching devices.

Abstract: AC/DC power converters having an under voltage lockout circuit with first and second thresholds and associated methods of operation are disclosed herein. In one embodiment, the first threshold is greater than the second threshold. The under voltage lockout circuit is configured to enable a current source to charge the capacitor when the voltage across the capacitor is less than the second threshold. The under voltage lockout circuit is configured to shut off the current source and to enable a pulse width modulator circuit to switch a transistor when the voltage is greater than the first threshold.

Abstract: An operation controller has a reference voltage generator, a starter circuit, and a switch element. The reference voltage generator is connected to an enable terminal to which an enable signal is supplied. After the enable signal is supplied and a start signal is generated, the reference voltage generator generates a reference voltage up to a stable value. After the reference voltage rises to the stable value, it generates a stop signal. When the enable signal is supplied, the starter circuit generates the start signal, and supplies it to the reference voltage generator. When the enable signal is no longer supplied or the stop signal is generated, the start signal is terminated. The switch element has one end connected to the enable terminal and the other end supplied with a prescribed voltage; it turns on when the start signal is generated, and turns off when the start signal is terminated.

Abstract: A DC/DC converter for use in power supply applications employing multiple parallel-connected converters employs a digital controller referenced to the secondary or output side of an isolation boundary and having non-isolated direct connections to secondary side components. The controller directly monitors output voltage and output current and uses feedback control techniques to precisely control these values in a desired manner. The DC/DC converter can implement so-called “droop” current sharing with increased accuracy arising from the secondary-side digital control, so that a desired balanced sharing of current across multiple converters can be achieved. The converter uses calibration establish accurate set points, and any of a variety of additional functions/features to attain operational goals.

Abstract: A resonant mode converter includes a PFC power converter having an input coupled to receive an input voltage. An LLC power converter is cascaded with the PFC power converter. The LLC power converter includes a transformer coupled to generate an output of the resonant mode converter. A feedback circuit is coupled to generate a first current representative of the output of the resonant mode converter. A control unit includes a current limiting circuit coupled to receive the first current and a second current generated in response to a reference voltage. The current limiting circuit is coupled to limit the first current in response to the second current. The control unit further includes an oscillator coupled to generate a control signal having a control frequency in response to the first current. The resonant mode converter output is controlled in response to the control frequency.

Abstract: A switching converter in which deterioration and breakage can be suppressed is provided. A switching converter whose area can be reduced is provided. The switching converter includes a switch connected to a power supply portion; a transformer connected to the power supply portion; a first rectifying and smoothing circuit and a second rectifying and smoothing circuit each connected to at least the transformer; and a switching control circuit which is connected to the first rectifying and smoothing circuit and the second rectifying and smoothing circuit and which controls operation of the switch. The switching control circuit includes a control circuit controlling on/off of the switch and operation of a starter circuit; and the starter circuit controlling startup of the control circuit. The starter circuit includes a transistor and a resistor each including a wide-gap semiconductor.

Abstract: A power supply system and method includes a switch state controller that is operational to control a switching power converter during certain power loss conditions that cause conventional switch state controllers to have diminished or no functionality. In at least one embodiment, during certain power loss conditions, such as when an auxiliary power supply is in standby mode or when the switching power converter is not operating, a power supply for the switch state controller does not provide sufficient operating power to the switch state controller during certain power loss conditions. In at least one embodiment, during such power loss conditions power is generated for the switch state controller using sense input and/or sense output currents of the switching power converter to allow an integrated circuit (IC) switch state controller to generate a control signal to control a switch of the switching power converter.

Abstract: An AC-DC power converter has a phase-shifting autotransformer based rectifiers and DC capacitors. Soft start of the AC-DC power converter is achieved by designing the autotransformer to operate at a low peak flux density at a point of AC voltage step application (initial turn on). The addition of a controlled impedance segregates capacitor charging from the initial magnetizing process of the autotransformer.

Abstract: A power adapter and an electrical connector for the power adapter operate to provide power to an electronic device such as a laptop computer. The power adapter includes a switch and a circuit for detecting whether or not the electrical connector is connected to the electronic device. If the adapter is not connected to an electronic device, the switch is opened so that no power is drawn from an AC supply. The electrical connector includes first and second conductors that are electrically connected to the detection circuit. The detection circuit detects a change in potential when the connector is plugged into an electronic device.

Abstract: Damage to an inverter due to an excessively high start-up current, when using space vector control without a voltage sensor in conjunction with small connection inductances, can be prevented with a method for controlling the inverter, and with a corresponding controller, wherein the controller is configured to transmit in a start-up phase of an inverter circuit a control signal to a control input of the inverter circuit, wherein the control signal simultaneously switches three first semiconductor switches, which are connected to a first DC voltage terminal of the inverter circuit, temporarily into a conducting state.

Abstract: A synchronous buck regulator includes a voltage regulator, a sample unit, a switch element, a comparison unit, a time delay unit, and a control unit. The sample unit is connected to the external power source for sampling a voltage drop in the external power source. The comparison unit is connected to the sample unit for outputting a result-high signal when the current passing through the sample unit is greater than a predetermined current rating. The time delay unit is connected to the comparison unit for outputting a first result-low signal. The control unit is connected to the time delay unit and outputs a first a low level signal to the switch element according to the result-low signal. The switch element connects the sample unit and the voltage regulator and can isolate the voltage regulator from the external power source when the low level signal is received.

Abstract: An electronic device includes a power supply, a load, and a switch circuit controlling the power supply. The switch circuit includes a control unit and a key switch capable of establishing an electrical connection between the power supply and the control unit in response to an operation by a user. When the key switch establishes the electrical connection, the control unit receives a supply voltage from the power supply and is charged-up by the supply voltage to generate a first control signal, the first control signal enables the power supply to power the load.

Abstract: A power supply device includes a transformer including a primary coil, a secondary coil, and a tertiary coil; a switching element connected via the primary coil to a direct-current power supply; a first rectifying-and-smoothing circuit rectifying and smoothing a voltage generated in the secondary coil; a control circuit turning on and off the switching element; a second rectifying-and-smoothing circuit rectifying and smoothing a voltage generated in the third coil to generate a driving voltage for the control circuit; and a starting circuit including a first transistor, a first resistor, and a first capacitor connected in series between the direct-current power supply and a ground, a second transistor connected between the direct-current power supply and the second rectifying-and-smoothing circuit, and a turn-off unit turning off at least the second transistor out of the first transistor and the second transistor when the first capacitor is charged to a predetermined voltage.

Abstract: A control circuit of a power converter for light-load power saving according to the present invention comprises a first feedback circuit coupled to an output voltage of the power converter to receive a first feedback signal. A second feedback circuit is coupled to the output voltage to receive a second feedback signal. A control circuit generates a switching signal for switching a transformer of the power converter and regulating the output voltage of the power converter in response to the first feedback signal and the second feedback signal. The switching signal is generated in accordance with the first feedback signal when an output load is high. The switching signal is generated in accordance with the second feedback signal during a light-load condition.

Abstract: A startup circuit for a switching-mode power supply (SMPS) includes a first voltage detector configured to trigger the switching-mode power supply from a first operation mode to a second operation mode when an input supply voltage exceeds a first threshold voltage, a current consumption in the first voltage detector in the first operation mode being determined by a reverse leakage current of a diode. A feedback circuit is coupled to the first voltage detector and being capable of maintaining a positive feedback loop. A second voltage detector is coupled to the first voltage detector and the feedback circuit, and is configured to trigger the switching-mode power supply to switch from the second operation mode to the first operation mode when the input supply voltage is below a second threshold voltage.

Abstract: In a clock-based soft-start circuit configured to generate a soft-start reference voltage that restrains an inrush current at an initialization of power supplied to a DC-DC converter, the clock-based soft-start circuit comprises a time setting unit configured to set a soft-start time period in response to a clock signal. A ramp circuit is configured to generate a soft-start reference voltage which is ramped upward or downward between a base level and a reference voltage level during the soft start time period set by the time setting unit. In this manner, the clock-based soft-start circuit is applicable for all DC-DC converters and the soft-start in a linear slope is possible.

Abstract: A power switch module for an electronic device includes a flip-flop circuit, a first current path for coupling a voltage source to the flip-flop circuit, and a second current path for coupling the voltage source to the flip-flop circuit. In response to a user power-on event, an output of the flip-flop circuit is at a first logic state for normally powering on the electronic device. In response to a user power-off event, the output of the flip-flop circuit is at a second logic state for normally powering off the electronic device. When the voltage source is suddenly interrupted, the output of the flip-flop circuit is kept at the first logic state but the electronic device is abnormally powered off. After the voltage source is resumed, the output of the flip-flop circuit kept at the first logic state reboots the abnormally powered-off electronic device.

Abstract: A power isolation system and method is disclosed. The system includes a transformer suitable for use in the power isolation system, and a semiconductor device electrically connected to the transformer to provide a reduction of the inrush current associated with powering the transformer, wherein the semiconductor device is activated upon power up based upon the previous shutdown state of the power isolation system to provide a soft start to the transformer, and after activation of the transformer, the semiconductor device is shorted in the system.

Abstract: A power converter that controls a collector current of a bipolar junction transistor (BJT) by controlling the base current to the BJT after having determined the gain of the BJT. A gain detection block determines a gain of the BJT during a first mode. A current calculation block generates a current setting for the base current based on the gain of the BJT determined by the gain detection block during a second mode distinct from the first mode. In some embodiments, the power converter may be included in a LED lamp system.

Abstract: A power supply includes an energy transfer element coupled between an input and an output. A switch is coupled to an input of the energy transfer element. A threshold detection circuit includes in an integrated circuit coupled to measure a signal from a resistive external circuit coupled between fourth and first external terminals of the integrated circuit during an initialization period after the fourth external terminal has been charged to a supply threshold value. A regulator circuit is coupled between second and fourth external terminals of the integrated circuit. The regulator circuit is coupled to charge the fourth external terminal to the supply threshold value during the initialization period. A selection circuit is coupled to the threshold detection circuit to select a parameter/mode of the integrated circuit in response to the measured signal.

Abstract: Various embodiments of a fluorescent lamp power supply are disclosed herein. In one embodiment, a power supply includes a power input connected to a pulse generator. The power supply also includes a filter connected to a variable pulse width output on the pulse generator and to the power input. The filter is adapted to substantially block at least one harmonic frequency component of the variable pulse width output and to substantially pass a fundamental frequency component of the variable pulse width output. The power supply also includes a power output connected to the filter, wherein an amplitude at the power output is related to the pulse width at the variable pulse width output.

Abstract: A starter of the grid-connected inverter and a control method thereof are disclosed. The starter comprises a controller, and a first switch and a first resistor connected in parallel. The controller includes an input end, and first and second output ends. The input end inspects the DC voltage signal from the inverter. When the DC voltage exceeds a predetermined voltage threshold, the first output end sends a first control signal to turn on the first switch, and the second output end sends a second control signal to make the grid-connected inverter enter into a chopping mode. There is a delay period between the send time of the first control signal and that of the second control signal.

Abstract: Methods and circuits related to power regulator start-up are disclosed. In one embodiment, a start-up circuit can include: (i) a delay circuit having a resistor and a capacitor, where the capacitor is coupled between ground and a common node; and (ii) a control chip that receives a reference voltage, and includes an input pin coupled to an input source, an output pin supplying power for a device, and a multiplexed pin coupled to the resistor at the common node to receive an enable signal. The start-up circuit outputs an electrical signal at the output pin based on a comparison of a voltage at the multiplexed pin against the reference voltage, and after a delay time determined by the capacitor and the reference voltage. The voltage at the multiplexed pin can increase continuously with a rising slope determined by input current flowing through the multiplexed pin during a start-up process.

Abstract: To provide a switching power supply device, and an operation condition setting method thereof, wherein it is possible to set an operation condition during an initialization period by adjusting the resistance value of a resistor that grounds an OUT terminal or IS terminal.

Abstract: A power source circuit which includes input portions, a limiting resistor connected to one of the input portions, a rectifier connected to the limiting resistor, a sampling resistor connected to the rectifier, output portions connected to the rectifier, a control circuit, and a switch circuit connected to the control circuit. The control circuit is connected to the two ends of the sampling resistor and the switch circuit is connected to the two ends of the limiting resistor. The control circuit is configured to output a first signal to the switch circuit if the current in the sampling resistor is greater than a predetermined value. The predetermined value is less than the level of current being consumed by a load in normal operation. The switch circuit is configured to isolate the sampling resistor when the first signal is received.

Abstract: The present invention relates to a power factor correction circuit and a driving method thereof. The power factor correction circuit receives an input voltage and maintains an output voltage at a constant level by controlling switching operation of a power switch connected to an inductor that supplies the output voltage. In this case, the power factor correction circuit controls switching operation of the power switch by differentiating a control structure for an output voltage respectively according to a stabilization period during which the output voltage is constantly maintained and a start-up period during which the output voltage is increased before being stabilized. In addition, the power factor correction circuit controls the switching operation of the power switch according to the control structure of the start-up period during a predetermined correction delay period from a time that the stabilization period starts.

Abstract: A chain-link converter including one or more phases. The one or more phases each includes one or more series-connected converter cells. The chain-link converter includes a power source connected to a converter cell of one of the one or more phases. A cost-efficient start-up of the converter is provided. The invention also relates to a corresponding static compensator system and a method.

Abstract: A device (1) for feeding electrical energy from an energy source with variable source voltage into an electric power supply network (15), said device (1) including a transformer (112) for galvanic isolation, a resonant inverter (11) with semi-conductor switches (a-d; A, B), one or several resonant capacitors (17; 18, 19; 20, 21) and one rectifier (113), is intended to provide high efficiency and have galvanic isolation. This is achieved in that the resonant inverter (11) is operated in the full resonant mode if the operating voltage is in an operation point (MPP) and in the hard-switching mode if the voltages exceed the operation point (MPP).