Abstract: Methods of regulating an output voltage of a multi-output isolated power converter are disclosed. One method includes allowing the output voltage to vary unregulated when the output voltage is below a threshold value and preventing the output voltage from increasing when the output voltage reaches the threshold value. Additional methods and multi-output power supplies are also disclosed.

Abstract: A method of controlling a power converter having at least one switching device for supplying an output voltage and a load current to a load is disclosed. The method includes sensing the output voltage and sensing the load current. The method further includes controlling a duty cycle of the switching device according to the sensed output voltage and a voltage control loop when a rate of change of the load current does not exceed a threshold level. The method also includes adjusting the duty cycle of the switching device set by the voltage control loop when the rate of change of the load current exceeds the threshold level.

Abstract: A power supply includes an input, an output, a reverse current protection circuit, a synchronous rectifier and an output choke. The reverse current protection circuit is configured for detecting a flyback voltage indicative of reverse current, and for deactivating the synchronous rectifier in response to detecting the flyback voltage. The flyback voltage can be detected a variety of ways, including across the output choke, across a switch in the synchronous rectifier, across the secondary winding of a power transformer, etc.

Abstract: A control circuit for controlling a switching device having a first terminal, a second terminal, and a control terminal is disclosed. The control circuit includes a first diode for coupling to the first terminal of the switching device, a second diode for coupling to the second terminal of the switching device, a first transistor for coupling to the control terminal of the switching device, and a second transistor coupled to the second diode. The first transistor is coupled to the first diode. The control circuit is configured to allow current flow in only one direction between the first and second terminals of the switching device.

Abstract: A cost effective integrated automotive solution for a charger transformer with minimized fringing flux and core grounding for reducing electromagnetic interference (EMI). The method provides an air gap filled with a mixture of an adhesive and ferrite powder that bonds the ferrite core sections together. In addition, the ground pin of the transformer is exposed through a groove in the pocket of the bobbin on which the core is mounted and an electrical contact is established between the exposed end of the ground pin and the core surface by means of a drop of epoxy.

Abstract: A method of controlling an isolated switching power converter that includes a transformer with a primary side and a secondary side, at least one primary switch coupled to the primary side of the transformer and at least one synchronous rectifier coupled to the secondary side of the transformer is disclosed. The method includes turning on the synchronous rectifier a first fixed time after turning on the primary switch and turning off the synchronous rectifier a second fixed time after turning off the primary switch. Power converters for operation according to this method are also disclosed, including power converters without an output inductor.

Abstract: A method of controlling a dimming level of one or more light emitting diodes (“LEDs”) includes receiving a phase cut dimming signal having a pulse width and frequency, generating a PWM signal having a duty cycle and frequency corresponding to the pulse width and frequency, respectively, of the phase cut dimming signal, and controlling a power converter coupled to the one or more LEDs with the generated PWM signal so that the dimming level of the one or more LEDs is a function of the duty cycle of the generated PWM signal. Example circuits for practicing this method and alternative methods are also disclosed.

Abstract: A method of operating an LED driver including a power converter to generate an output current for powering an LED and to provide active power factor correction is disclosed. The power converter is coupled between an input to receive a rectified AC voltage and an output for providing the output current to the LED. The method includes operating the power converter at a substantially fixed frequency in an open loop mode based on a current through the inductive element and the rectified AC voltage. LED drivers operable in accordance with the disclosed method are disclosed.

Abstract: A switching power converter includes an input for receiving an input voltage, an output for providing an output voltage, a controller, and a power circuit coupled between the input and the output and including at least one switch. The controller is configured to determine a duty cycle for the switch to regulate the output voltage and control the switch with a PWM drive signal having an on-time and an off-time. The PWM drive signal has a constant frequency and a duty cycle equal to the determined duty cycle when the determined duty cycle is greater than or equal to a minimum duty cycle. The PWM drive signal has a variable frequency and a duty cycle equal to the minimum duty cycle when the determined duty cycle is less than the minimum duty cycle.

Abstract: A modular-based, zero-current-switched (ZCS), isolated full-bridge boost converter with multiple inputs is disclosed. Each converter module is used to match the connected input source and control the amount of power drawn from the source. The power from various sources are combined together and delivered to the load through a multiphase transformer. The input inductor of each boost-derived converter module keeps the input current constant and acts as a current source to drive the multiphase transformer through a phase-shifted-controlled full bridge converter. By connecting an auxiliary circuit across the full-bridge input in each module, the transformer leakage inductance and output capacitance of the switching devices are used to create resonant paths for facilitating zero-current-switching of all switching devices.

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: Multi-winding magnetic structures and methods of making multi-winding magnetic structures are disclosed. In one embodiment, a multi-winding magnetic structure includes a core constructed of a magnetic material and a plurality of windings. The core includes a core top, a core bottom, and a plurality of columns. The core top has an exterior edge defining a shape of the core top. A central section of the core top has a substantially constant thickness that defines a thickness of the core top. The core bottom is beneath the core top and has an exterior edge defining a shape of the core bottom. A central section of the core bottom has a substantially constant thickness that defines a thickness of the core bottom. The thickness of one of the core bottom and the core top decreases from an edge of its central section to its exterior edge. The plurality of columns extends from the core bottom to the core top and the plurality of windings are wound around the columns.

Abstract: Multi-level power converters are disclosed. In one embodiment, a multi-level power converter includes an input for receiving an input voltage and a converter output for providing a variable output voltage. The multi-level power converter includes a plurality of switching circuits. Each switching circuit is connected to the input in parallel with each other switching circuit. Each switching circuit includes an output. Each switching circuit is selectively operable to couple its output to the input voltage or a reference voltage. The multi-level power converter includes a parallel multi-winding autotransformer (PMA). The PMA includes a plurality of windings and a magnetic core having a plurality of magnetically connected columns. Each winding is positioned around a different one of the columns and has a beginning and an end. The output of each switching circuit is coupled to the beginning of a different winding. The end of each winding is connected to the converter output in parallel with each other winding.

Abstract: A feedthrough capacitor assembly for attachment to a mount having an opening is disclosed. The assembly includes a feedthrough terminal adapted for insertion through said opening for coupling a signal from a first side of the mount to a second side of the mount. The assembly includes a first conductive region extending about and electrically coupled to the feedthrough terminal and a second conductive region extending about the first conductive region. A plurality of capacitors are electrically coupled between the first conductive region and the second conductive region. The plurality of capacitors are arranged about the feedthrough terminal with each capacitor having about the same capacitance as each of the other capacitors.

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.

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.

Abstract: Various methods related to air moving devices in electronic systems are disclosed. Various electronic systems including controlled air moving devices are also disclosed. Thus, one example electronic system includes an air moving device and a controller for controlling the air moving device. The controller is configured to selectively control a rotational speed of the air moving device. The controller is configured to vary the rotational speed within a range bounded by and including a first rotational speed and a second rotational speed during a time that a target rotational speed is within the range.

Abstract: Fastener retainer brackets and related assemblies and methods are disclosed. One example fastener retainer bracket includes a mounting portion and a restricting portion coupled to the mounting portion. The mounting portion defines a plurality of openings structured to receive a plurality of fasteners received in a support structure. The restricting portion is adapted to permit tool access to heads of the plurality of fasteners when the plurality of fasteners extend through the plurality of openings of the mounting portion. The restricting portion is adapted to contact the head of at least one of the fasteners to inhibit removal of that fastener from the support structure.

Abstract: Various methods related to air moving devices in electronic systems are disclosed. Various electronic systems including controlled air moving devices are also disclosed. Thus, one example electronic system includes an air moving device, a sensor for monitoring an operating parameter of the electronic system and generating a signal representative of the operating parameter, and a controller for controlling the air moving device. The controller is configured to selectively control a rotational speed of the air moving device, to receive the signal representative of the operating parameter, and to delay changing the rotational speed of the air moving device in response to the signal representative of the operating parameter.

Abstract: Power converters for photovoltaic (PV) systems and maximum power point tracking techniques are disclosed. One example power converter for a PV system includes an input for coupling to the PV system, an output for providing an output voltage, and a switch coupled between the input and the output. The input is configured to receive an input voltage (Vin) and input current (Iin) from the PV system. The power converter includes a controller configured for controlling operation of the switch using a control signal C. C is a function of at least the input voltage, the input current and a variable (K).