Abstract: A magnetic core for use with a printed circuit board transformer can include one or more inside corners of the magnetic core formed to include a curved channel that serves as a strain relief and facilitates positioning a printed circuit board within a core window defined by the core. The magnetic core can be an E-core. A center post of the E-core can define a notch configured to receive a complementary tab of a printed circuit board of the printed circuit board transformer. A center post of the E-core can be shorter than outside legs of the E-core, so that when assembled with an I-core a resulting core has an air gap. The core can be made of a ferrite material. A printed circuit board transformer can include a printed circuit board having one or more turns of a conductive trace disposed thereon and a magnetic core as described above.

Abstract: A quasi-planar transformer can include a first winding comprising one or more turns of wire, a second winding comprising one or more turns of a conductive trace disposed on a printed circuit board, and a magnetic core positioned with respect to the first and second windings so as to provide a magnetic flux path coupling the first and second windings. The first winding can be a primary winding having a first half wound in a clockwise direction on a first side of the printed circuit board and a second half wound in a counterclockwise direction on a second side of the printed circuit board, wherein the first and second halves are formed of a single continuous wire. The single continuous wire can pass through an opening in the printed circuit board. The first and second halves of the primary winding can be secured to the printed circuit board.

Abstract: A method of assembling a quasi-planar transformer can include passing a continuous wire through an opening in a printed circuit board having one or more printed circuit traces that define one or more printed circuit windings of the quasi-planar transformer, winding the continuous wire in a first direction to form a first half of a wire-wound winding on a first side of the printed circuit board, and winding the continuous wire in a second direction opposite the first to form a second half of the wire-wound winding on a second side of the printed circuit board. The method can further include securing the first and second halves of the winding to the printed circuit board. The continuous magnet wire can be self-bonding wire and securing the first and second halves of the winding can include applying heat to the assembly.

Abstract: Disclosed herein is an improved flyback converter that separates the magnetic components of the converter into a transformer and a separate, discrete energy storage inductor. This arrangement can improve the operating efficiency of the converter by reducing the commutation losses as compared to a conventional flyback converter. The magnetic components may be constructed on separate magnetic cores or may be constructed on magnetic cores having at least one common element, thereby allowing for at least partial magnetic flux cancellation in a portion of the core, reducing core losses.

Abstract: Disclosed herein is an improved flyback converter that separates the magnetic components of the converter into a transformer and a separate, discrete energy storage inductor. This arrangement can improve the operating efficiency of the converter by reducing the commutation losses as compared to a conventional flyback converter. The magnetic components may be constructed on separate magnetic cores or may be constructed on magnetic cores having at least one common element, thereby allowing for at least partial magnetic flux cancellation in a portion of the core, reducing core losses.

Abstract: A two-stage power converter can incorporate a buck pre-regulator and a resonant bus converter. Such a converter may be operated to achieve unconditional soft switching operation (zero voltage switching a/k/a ZVS) over a wide input and output range, while delivering excellent power conversion efficiency at lower power levels and in a no load condition.

Abstract: The described shielding system comprises a first shield and a second shield. The first shield comprises a first plurality of conductive segments extending from a first location. The first plurality of conductive segments are separated from each other by a first plurality of gaps. The second shield comprises a second plurality of conductive segments extending from a second location. The second plurality of conductive segments are separated from each other by a second plurality of gaps. An insulator may be interposed between the first shield and the second shield. The first plurality of gaps may at least partially align with the second plurality of conductive segments and the second plurality of gaps may at least partially align with the first plurality of conductive segments.

Abstract: Disclosed herein is an improved flyback converter that separates the magnetic components of the converter into a transformer and a separate, discrete energy storage inductor. This arrangement can improve the operating efficiency of the converter by reducing the commutation losses as compared to a conventional flyback converter. The magnetic components may be constructed on separate magnetic cores or may be constructed on magnetic cores having at least one common element, thereby allowing for at least partial magnetic flux cancellation in a portion of the core, reducing core losses.

Abstract: Isolated buck converters can be an efficient solution in applications that deal with wide variations in input and/or output voltage. The double ended embodiments of such converters can also offer improved transformer utilization. Such converters can be operated in fixed frequency DCM mode operation or variable frequency boundary conduction mode (BCM). The buck/energy storage inductor may be placed in series with primary or secondary winding of the isolation transformer The inherent leakage inductance of the isolation transformer may also utilized as part of the buck inductance. If the leakage inductance of the isolation transformer is sufficiently high (such as in wireless power transfer applications), such converters can use the leakage inductance as the buck inductor.

Abstract: Disclosed herein is an improved flyback converter that separates the magnetic components of the converter into a transformer and a separate, discrete energy storage inductor. This arrangement can improve the operating efficiency of the converter by reducing the commutation losses as compared to a conventional flyback converter. The magnetic components may be constructed on separate magnetic cores or may be constructed on magnetic cores having at least one common element, thereby allowing for at least partial magnetic flux cancellation in a portion of the core, reducing core losses.

Abstract: A two-stage power converter can incorporate a buck pre-regulator and a resonant bus converter. Such a converter may be operated to achieve unconditional soft switching operation (zero voltage switching a/k/a ZVS) over a wide input and output range, while delivering excellent power conversion efficiency at lower power levels and in a no load condition.

Abstract: A two-stage power converter can incorporate a buck pre-regulator and a resonant bus converter. Such a converter may be operated to achieve unconditional soft switching operation (zero voltage switching a/k/a ZVS) over a wide input and output range, while delivering excellent power conversion efficiency at lower power levels and in a no load condition.

Abstract: A two-stage power converter can incorporate a buck pre-regulator and a resonant bus converter. Such a converter may be operated to achieve unconditional soft switching operation (zero voltage switching a/k/a ZVS) over a wide input and output range, while delivering excellent power conversion efficiency at lower power levels and in a no load condition.

Abstract: A flyback converter can include a series-parallel mode (SPM) active clamp circuit. The active clamp circuit, coupled in parallel with the primary coil, may include multiple networks in parallel. The first network, comprising a switch, one or more snubber capacitors, and one or more diodes, may be configured to absorb and retain the leakage energy from the leakage inductance of the flyback converter. The second network, comprising another switch and a diode, may be configured to create a circulating circuit for the flow of current through the primary coil in a reverse direction and clamp the current to a threshold level. With the active clamp circuit, the flyback converter may first re-capture the leakage energy in the active clamp circuit and then recover it back to the power source.

Abstract: A flyback converter can include a series-parallel mode (SPM) active clamp circuit. The active clamp circuit, coupled in parallel with the primary coil, may include multiple networks in parallel. The first network, comprising a switch, one or more snubber capacitors, and one or more diodes, may be configured to absorb and retain the leakage energy from the leakage inductance of the flyback converter. The second network, comprising another switch and a diode, may be configured to create a circulating circuit for the flow of current through the primary coil in a reverse direction and clamp the current to a threshold level. With the active clamp circuit, the flyback converter may first re-capture the leakage energy in the active clamp circuit and then recover it back to the power source.

Abstract: A power conversion system for use with a photovoltaic (PV) power source may include a DC/DC converter for converting a first DC voltage into a second DC voltage, an isolation transformer, an inverter for converting DC power to AC power, and at least one controller for controlling the DC/DC converter and the inverter. The controller may be configured to operate the DC/DC converter as a buck converter or a boost converter based, at least in part, on whether the first DC voltage is less or greater than a reference voltage. Additionally, the controller may operate the converter according to a maximum power point tracking algorithm. Further, the controller may be configured to operate the inverter to control the DC voltage at the inverter's input as a function of the AC voltage at the inverter's output. Example embodiments of power systems, DC/DC converters, DC/AC inverters and related methods are also disclosed.

Abstract: A cost effective solution for construction of high frequency, double ended, isolated, push pull, center tapped power transformers operating in continuous/discontinuous mode with minimized winding proximity losses comprises at least two identical sets of windings with identical coupling coefficients. Each set of windings consists of at least one primary winding and at least one secondary winding tightly coupled to each other. Both the sets of windings are loosely coupled to each other with a magnetic field isolating separator.

Abstract: A driver circuit for one or more LEDs includes a power circuit having an output terminal, a capacitor coupled to the output terminal and a switch, and a control circuit coupled to the power circuit for controlling the power circuit. The control circuit is configured to operate the switch for coupling a resistance in series with the capacitor in response to detecting an open circuit condition at the output terminal. Additionally, or alternatively, the driver circuit may include a switched mode power supply, and the control circuit may be configured to switch operation of the switched mode power supply from a current control mode to a voltage control mode, and reduce a current setting for the current control mode, in response to detecting an open circuit condition at the output terminal.

Abstract: A method of generating an output voltage from a variable input voltage with a power factor correction (PFC) system is disclosed. The PFC system includes a first power rail and a second power rail connected in parallel between an input for receiving the input voltage and an output for outputting the output voltage. The method includes operating one or both of the first power rail and the second power rail to generate the output based, at least in part, on whether the input voltage exceeds a threshold voltage. Power supplies and PFC systems suitable for performing the method are also disclosed.

Abstract: A power system includes a plurality of DC/DC converters and a DC/AC inverter. The plurality of DC/DC converters having outputs electrically connected in parallel for supplying a DC voltage bus to an input of the DC/AC inverter. The plurality of DC/DC converters each include a maximum power point tracker (MPPT). Various DC/DC converters and DC/AC inverters suitable for use in this system and others are also disclosed.