Abstract: A transmitter comprising a planar antenna including a ground plane and first and second spiral radiating elements wrapping around the ground plane, and a driving circuit. Proximal ends of the spiral radiating elements terminate near points located along a perimeter of the ground plane. Exactly one of the first and second spiral radiating elements are electrically isolated from the ground plane. The first and second spiral radiating elements are wound in the same direction for approximately a single turn and increase in thickness for approximately three-fourths of the turn. The driving circuit drives one of the first and second spiral radiating elements.

Abstract: A wirelessly-powered locker comprises a transmitting antenna mounted to or embedded within a locker wall and a receiving antenna coupled to the lock. A power source connected to a transmitter transmits power to a wireless receiver in the lock via radiated wireless power. The wireless power operating frequency may be in the ISM band. The lock may further include wireless communication means to allow wireless transmission of an unlock code to the lock or wireless monitoring of the lock.

Abstract: A wirelessly-powered locker comprises a transmitting antenna mounted to or embedded within a locker wall and a receiving antenna coupled to the lock. A power source connected to a transmitter transmits power to a wireless receiver in the lock via radiated wireless power. The wireless power operating frequency may be in the ISM band. The lock may further include wireless communication means to allow wireless transmission of an unlock code to the lock or wireless monitoring of the lock.

Abstract: A controller for a power converter and method of operating the same. In one embodiment, the controller includes an inductor-inductor-capacitor (“LLC”) controller configured to receive an error signal from an error amplifier to control a switching frequency of an LLC stage of the power converter to regulate an output voltage thereof. The controller also includes a power factor correction (“PFC”) controller configured to control a bus voltage produced by a PFC stage of the power converter and provided to the LLC stage so that an average switching frequency thereof is substantially maintained at a desired switching frequency.

Abstract: A controller for use with a power converter and method of operating the same. In one embodiment, the controller includes a transformer voltage sensing circuit configured to produce a preliminary bus voltage sample. The controller also includes a frequency correction circuit coupled to the transformer voltage sensing circuit and configured to correct the preliminary bus voltage sample to produce an estimate of an internal bus voltage of the power converter.

Abstract: A start-up circuit for a power adapter and method of operating the same. In one embodiment, the power adapter includes a start-up circuit configured to provide an initial bias voltage for the power adapter. The power adapter also includes a crowbar circuit configured to turn on the start-up circuit upon loss of an ac mains voltage supplied to the power adapter.

Abstract: A controller for use with a power converter and method of operating the same. In one embodiment, the controller includes a gate drive terminal configured to provide a gate drive signal to enable conductivity of a power switch during a first portion of a switching interval and to disable conductivity of the power switch during a second portion of the switching interval. The controller also includes a current sense terminal configured to receive a power switch signal indicative of a current in the power switch during the first portion of the switching interval, and receive a control signal to operate the power converter or provide a status signal indicative of an operating condition of the power converter during the second portion of the switching interval.

Abstract: A power converter employing a control system configured to make multiple functional use of a circuit node therein and method of operating the same. In one embodiment, the power converter includes a power train including at least one power switch. The power converter also includes a control system including an opto-isolator circuit, including a resistor, configured to receive an output signal from the power converter and provide a feedback signal to a feedback node for the control system to provide a switch control signal for the at least one power switch. The control system also includes a current source configured to produce multiple voltage levels at the feedback node in accordance with the resistor, thereby enabling multiple functional uses of the feedback node.

Abstract: A resonant power converter draws current from a source that provides a supply current. Multiple quasi-resonant converters are interleaved and each quasi-resonant converter receives the supply current and forms a phase-shifted current according to drive signals supplied by a controller. Each phase-shifted current includes a dead-time delay and is phase-shifted relative to the other phase-shifted currents. The dead-time delay is determined as a time value within a calculated dead-time delay range having a dead-time delay minimum and a dead-time delay maximum. The outputs of each quasi-resonant converter are added together thereby reducing the AC components of current. Two, three, or four quasi-resonant power converters can be interleaved, each forming phase-shifted currents that are phase-shifted relative to the other phase-shifted currents.

Abstract: A control system for a power converter with reduced power dissipation and method of operating the same. In one embodiment, the control system includes a first controller coupled to a primary winding of a transformer and configured to control a duty cycle of a power switch to regulate an output characteristic of the power converter. The control system also includes a second controller configured to provide a signal to one of a secondary winding of the transformer and a circuit element spanning an isolation boundary of the transformer in response to a dynamic change of the output characteristic to trigger the first controller to initiate the duty cycle for the power switch.

Abstract: A power converter employing a control system configured to make multiple functional use of a circuit node therein and method of operating the same. In one embodiment, the power converter includes a power train including at least one power switch. The power converter also includes a control system including an opto-isolator circuit, including a resistor, configured to receive an output signal from the power converter and provide a feedback signal to a feedback node for the control system to provide a switch control signal for the at least one power switch. The control system also includes a current source configured to produce multiple voltage levels at the feedback node in accordance with the resistor, thereby enabling multiple functional uses of the feedback node.

Abstract: A power converter including an inductor-inductor-capacitor stage and method of operating the same. In one embodiment, the power converter includes an inductor-inductor-capacitor (LLC) stage coupled to an input of said power converter. The power converter also includes a controller configured to control a switching frequency of the LLC stage as a function of an input voltage of the power converter.

Abstract: A controller for use with a power converter and method of operating the same. In one embodiment, the controller includes a light emitting diode string controller configured to receive a dimmer signal and control a level of current in a light emitting diode string in response to the dimmer signal. The controller also includes a power converter controller configured to receive the dimmer signal and control an output current of the power converter that is a multiple of the level of current in the light emitting diode string.

Abstract: A power adapter including a power reducer for no-load or light load applications and method of operating the same. In one embodiment, the power adapter includes a capacitor coupled to an input of the power adapter, and a bleeder switch coupled in parallel with the capacitor. The power adapter also includes a detection circuit configured to sense an ac mains voltage at the input of the power adapter and turn on the bleeder switch upon detection of a loss of the ac mains voltage. In addition to or in lieu of, the power adapter may include a power converter, and a disconnect switch configured to disconnect the ac mains voltage from the power converter in response to a signal from a load.

Abstract: A controller for a power converter and method of operating the same. In one embodiment, the controller includes an inductor-inductor-capacitor (“LLC”) controller configured to receive an error signal from an error amplifier to control a switching frequency of an LLC stage of the power converter to regulate an output voltage thereof. The controller also includes a power factor correction (“PFC”) controller configured to control a bus voltage produced by a PFC stage of the power converter and provided to the LLC stage so that an average switching frequency thereof is substantially maintained at a desired switching frequency.

Abstract: A burst mode controller for a power converter and method of operating the same. In one embodiment, the burst mode controller includes a burst mode initiate circuit configured to initiate a burst mode of operation when a signal representing an output voltage of the power converter crosses a first burst threshold level. The burst mode controller also includes a voltage elevate circuit configured to provide a voltage elevate signal to raise the output voltage if a time window expires before the signal representing the output voltage of the power converter crosses a second burst threshold level.

Abstract: A power converter employing a controller configured to increase a dead time between conduction periods of first and second power switches therein and method of operating the same. In one embodiment, the power converter includes first and second power switches coupled to an input thereof, and a sensor configured to provide a sensed signal representative of at least one of a current level and a power level of the power converter. The power converter also includes a controller configured to increase a dead time between conduction periods of the first and second power switches when the sensed signal indicates a decrease of at least one of the current level and the power level of the power converter.

Abstract: A power converter including a power switch, a controller for controlling a switching frequency thereof, and a magnetic device with a non-uniform gap. In one embodiment, the power converter includes a power switch and a magnetic device coupled to the power switch and having a non-uniform gap. The power converter also includes a controller having a detector configured to sense a condition representing an output power of the power converter. A control circuit of the controller is configured to control a switching frequency of the power switch as a function of the condition and control a duty cycle of the power switch to regulate an output characteristic of the power converter.

Abstract: Generally, methods and processes for assembling magnetic components are presented herein. More specifically, conductors are wound around a substantially hollow bobbin. Portions of the conductors may be temporarily positioned outside the bobbin through slots in the flanges of the bobbin during the assembly process. Insulating layers may be wrapped around the conductors. The center legs of a pair of magnetic core halves may be inserted into the bobbin. The base of the magnetic core halves may have a passage to allow a conductor to pass therethrough at a height less than the height of the base.

Abstract: A start-up circuit for a power adapter and method of operating the same. In one embodiment, the power adapter includes a start-up circuit configured to provide an initial bias voltage for the power adapter. The power adapter also includes a crowbar circuit configured to turn on the start-up circuit upon loss of an ac mains voltage supplied to the power adapter.