Abstract: A DC/DC converter may be formed out of the combination of a first converter that is optimized to transfer energy from a voltage source to a load, and a second converter that receives a control signal derived from the load voltage to regulate the load voltage. The DC/DC converter may be configured as a sigma converter, a delta converter, or a sigma-delta converter. The mode of operation being selected according to the source voltage or the load voltage, either of which may vary over a wide range.

Abstract: A resonant converter includes a transformer, a resonant network, control circuit, primary and secondary circuits. One of the primary switches is turned on from a first switching moment until a second switching moment. The resonant network is coupled between the primary circuit and the primary winding. A current of the resonant network changes a direction at a first moment between the first and second switching moments. The secondary circuit is coupled to the secondary winding. One of the secondary switches is turned on during first and second preset time interval to increase the current in a direction by the secondary winding being clamped by a preset voltage, in which the output current is increased in an opposite direction or equal to zero.

Abstract: A resonant converter includes a transformer, a resonant network, control circuit, primary and secondary circuits. One of the primary switches is turned on from a first switching moment until a second switching moment. The resonant network is coupled between the primary circuit and the primary winding. A current of the resonant network changes a direction at a first moment between the first and second switching moments. The secondary circuit is coupled to the secondary winding. One of the secondary switches is turned on during first and second preset time interval to increase the current in a direction by the secondary winding being clamped by a preset voltage, in which the output current is increased in an opposite direction or equal to zero.

Abstract: A DC/DC converter may be formed out of the combination of a first converter that is optimized to transfer energy from a voltage source to a load, and a second converter that receives a control signal derived from the load voltage to regulate the load voltage. The DC/DC converter may be configured as a sigma converter, a delta converter, or a sigma-delta converter. The mode of operation being selected according to the source voltage or the load voltage, either of which may vary over a wide range.

Abstract: A gradient amplifier driver stage circuit includes: a gradient coil and a plurality of gradient driver modules electrically cascaded with each other and forming an output end, the output end being electrically connected to the gradient coil, wherein each gradient driver module includes a pre-stage power supply and a bridge amplifier connected in parallel, output voltage of the pre-stage power supplies of the plurality of gradient driver modules are the same, and each gradient driver module is configured to provide an inductive voltage drop and a resistive voltage drop on the gradient coil.

Abstract: The present disclosure provides a gradient amplifier driver stage circuit, a gradient amplifier system and a control method thereof. The gradient amplifier driver stage circuit includes: a gradient coil and a plurality of gradient driver modules electrically cascaded with each other and forming an output end, the output end being electrically connected to the gradient coil, wherein each gradient driver module includes a pre-stage power supply and a bridge amplifier connected in parallel, output voltage of the pre-stage power supplies of the plurality of gradient driver modules are the same, and each gradient driver module is configured to provide an inductive voltage drop and a resistive voltage drop on the gradient coil.

Abstract: A power supply includes multiple power modules and a control circuit. Input terminals of the power modules are connected in star connection such that each power module receives a phase input voltage. Output terminals of the power modules are connected in parallel. Each power modules includes a first and a second converter. The first converter converts the phase input voltage into an intermediate bus voltage. The second converter outputs a DC supply voltage according to the intermediate bus voltage. The control circuit is coupled to the power modules and configured to output first and second driving signals to control the first and second converters in the power modules. A bus voltage average value is calculated by the control circuit according to the intermediate bus voltages of the power modules, and the first and the second driving signals for the power modules are generated according to the bus voltage average value.

Abstract: A flyback power converter includes a hybrid clamp circuit and a corresponding power management unit that substantially optimizes the performance of the flyback power converter in its entire line and load ranges. The clamp circuit, which is connected in parallel to a primary winding of the flyback transformer, includes a parallel combination of a capacitor and resistor that is connected in series with a parallel combination of a switch and a diode. By sensing the operating conditions, the power management circuit configures the clamp circuit either as a passive clamp or as an active clamp. In the passive-clamp configuration, the switch is kept turned off. In the active-clamp configuration, the switch operates with pulse-width modulation (PWM) which enables ZVS turn-on of the main switch.

Abstract: A flyback power converter includes a hybrid clamp circuit and a corresponding power management unit that substantially optimizes the performance of the flyback power converter in its entire line and load ranges. The clamp circuit, which is connected in parallel to a primary winding of the flyback transformer, includes a parallel combination of a capacitor and resistor that is connected in series with a parallel combination of a switch and a diode. By sensing the operating conditions, the power management circuit configures the clamp circuit either as a passive clamp or as an active clamp. In the passive-clamp configuration, the switch is kept turned off. In the active-clamp configuration, the switch operates with pulse-width modulation (PWM) which enables ZVS turn-on of the main switch.

Abstract: A power supply having an input and an output, includes a power converter coupled between the input and output of the power supply including at least one switch that is controlled by comparing a sensed voltage, the sensed voltage corresponding to a current flowing through the switch, to a reference voltage. A controller, in response to a change detected in a switching frequency of the switch, reduces audible noise generated by the power supply by at least one of: adjusting the reference voltage; adjusting the current sense voltage; or adjusting a resistance used to generate the sensed voltage.

Abstract: A power supply having an input and an output, includes a power converter coupled between the input and output of the power supply including at least one switch that is controlled by comparing a sensed voltage, the sensed voltage corresponding to a current flowing through the switch, to a reference voltage. A controller, in response to a change detected in a switching frequency of the switch, reduces audible noise generated by the power supply by at least one of: adjusting the reference voltage; adjusting the current sense voltage; or adjusting a resistance used to generate the sensed voltage.

Abstract: A power supply having an input and an output, includes a power converter coupled between the input and output of the power supply including at least one switch that is controlled by comparing a sensed voltage, the sensed voltage corresponding to a current flowing through the switch, to a reference voltage. A controller, in response to a change detected in a switching frequency of the switch, reduces audible noise generated by the power supply by at least one of: adjusting the reference voltage; adjusting the current sense voltage; or adjusting a resistance used to generate the sensed voltage.

Abstract: A variable inductor comprises one or more magnetic cores providing magnetic flux paths. An inductor coil is wound around one or more inductor sections of the one or more magnetic cores. An inductor magnetic flux flows through one or more closed flux paths along the inductor sections of the magnetic core. A control coil is wound around one or more control sections of the one or more magnetic cores. A control magnetic flux flows through one or more closed flux paths along the control sections of the magnetic core. Under this arrangement, the inductor magnetic flux substantially does not flow through the control sections of the magnetic core and the control magnetic flux substantially does not flow through the inductor sections of the magnetic core. The closed flux paths associated with the inductor magnetic flux and the closed flux paths associated with the control magnetic flux share one or more common sections of the magnetic core not including the control sections and inductor sections.

Abstract: A variable inductor comprises one or more magnetic cores providing magnetic flux paths. An inductor coil is wound around one or more inductor sections of the one or more magnetic cores. An inductor magnetic flux flows through one or more closed flux paths along the inductor sections of the magnetic core. A control coil is wound around one or more control sections of the one or more magnetic cores. A control magnetic flux flows through one or more closed flux paths along the control sections of the magnetic core. Under this arrangement, the inductor magnetic flux substantially does not flow through the control sections of the magnetic core and the control magnetic flux substantially does not flow through the inductor sections of the magnetic core. The closed flux paths associated with the inductor magnetic flux and the closed flux paths associated with the control magnetic flux share one or more common sections of the magnetic core not including the control sections and inductor sections.

Abstract: A power supply having an input and an output, includes a power converter coupled between the input and output of the power supply including at least one switch that is controlled by comparing a sensed voltage, the sensed voltage corresponding to a current flowing through the switch, to a reference voltage. A controller, in response to a change detected in a switching frequency of the switch, reduces audible noise generated by the power supply by at least one of: adjusting the reference voltage; adjusting the current sense voltage; or adjusting a resistance used to generate the sensed voltage.

Abstract: Control device for a switching converter structure comprising at least a first and a second interleaved converter, wherein the control device is configured to designate one converter as master and at least the other converter as slave, to set a time delay of the operating cycle of the slave converter and to synchronize the master and the at the least one slave converter.

Abstract: Control device for a switching converter structure comprising at least a first and a second interleaved converter, wherein the control device is configured to designate one converter as master and at least the other converter as slave, to set a time delay of the operating cycle of the slave converter and to synchronize the master and the at the least one slave converter.

Abstract: A single-stage input-current-shaping (S2ICS) flyback converter achieves substantially reduced conduction losses in the primary side of the S2ICS flyback converter by connecting a bypass diode between the positive terminal of a full-bridge rectifier and the positive terminal of an energy-storage capacitor. An effective current interleaving between an energy-storage inductor and the bypass diode is thus obtained in the S2ICS flyback converter around the peak of the rectified line voltage, resulting in a significantly reduced input-current ripple and reduced current stress on the switch. Further, by rearranging the rectifiers in the ICS part of the S2ICS flyback converter in such a way that the energy-storage capacitor and the ICS inductor are connected to the ac line voltage through only two rectifiers, one diode forward-voltage drop is eliminated, which results in a substantially reduced conduction loss in the primary-side rectifiers.

Abstract: A single-stage input-current-shaping (S2ICS) flyback converter achieves substantially reduced conduction losses in the primary side of the S2ICS flyback converter by connecting a bypass diode between the positive terminal of a full-bridge rectifier and the positive terminal of an energy-storage capacitor. An effective current interleaving between an energy-storage inductor and the bypass diode is thus obtained in the S2ICS flyback converter around the peak of the rectified line voltage, resulting in a significantly reduced input-current ripple and reduced current stress on the switch. Further, by rearranging the rectifiers in the ICS part of the S2ICS flyback converter in such a way that the energy-storage capacitor and the ICS inductor are connected to the ac line voltage through only two rectifiers, one diode forward-voltage drop is eliminated, which results in a substantially reduced conduction loss in the primary-side rectifiers.

Abstract: A single-stage input-current-shaping (S.sup.2 ICS) converter of the present invention integrates a voltage-doubler-rectifier front-end with a DC/DC output stage. Two families of voltage-doubler S.sup.2 ICS converters are disclosed. In one family, a 2-terminal dither source is provided between a boost inductor and a common input terminal of a storage capacitor and the DC/DC output stage. The 2-terminal dither source includes two paths connected in parallel: a first path for charging and a second path for discharging the boost inductor at a high frequency (HF). In the other family, a 3-terminal dither source includes a third terminal coupled to a pulsating node of the DC/DC output stage.