A wireless power system includes a power source, power receiver, and components thereof. The system can also include a parasitic antenna that can improve the coupling to the power source in various modes. The antenna can have both a variable capacitor and a variable inductor, and both of those can be changed in order to change characteristics of the matching.

Packaging and details of a wireless power device

A light emitting diode (LED) lighting system includes a PFC and output voltage controller and a LED lighting power system. The controller advantageously operates from an auxiliary voltage less than a link voltage generated by the LED lighting power system. The common reference voltage allows all the components of lighting system to work together. A power factor correction switch and an LED drive current switch are coupled to the common reference node and have control node-to-common node, absolute voltage that allows the controller to control the conductivity of the switches. The LED lighting system can utilize feed forward control to concurrently modify power demand by the LED lighting power system and power demand of one or more LEDs. The LED lighting system can utilize a common current sense device to provide a common feedback signal to the controller representing current in at least two of the LEDs.

Power control system for current regulated light sources

In at least one embodiment, a controller allows triac-based dimmer to properly function and dim a load whose voltage is regulated by a switching power converter. In at least one embodiment, the switching power converter includes a switch to control voltage conversion of an input voltage to the switching power converter, wherein phase delays are introduced in the input voltage by a triac-based dimmer during a dimming period. In at least one embodiment, the controller is configured to control the switch of the switching power converter to establish an input resistance of the switching power converter during a dimming portion of the input voltage, wherein the input resistance allows the triac-based dimmer to phase modulate a supply voltage to the dimmer so that an output voltage of the dimmer has a substantially uninterrupted phase delay during each half-cycle of the supply voltage during the dimming period.

Switching power converter control with triac-based leading edge dimmer compatibility

A light emitting diode (LED) lighting system includes a power factor correction (PFC) controller that determines at least one power factor correction control parameter from phase delays of a phase modulated signal. In at least one embodiment, a peak voltage of the phase modulated signal is a PFC control parameter used by the PFC controller to control power factor correction and generation of a link voltage by a PFC LED driver circuit. The phase delays are related to a peak voltage of the phase modulated signal. Thus, in at least one embodiment, detecting the phase delay in one or more cycles of the phase modulated signal allows the PFC controller to determine the peak voltage of the phase modulated signal.

Lighting system with power factor correction control data determined from a phase modulated signal

A system and method map dimming levels of a lighting dimmer to light source control signals using a predetermined lighting output function. The dimmer generates a dimmer output signal value. At any particular period of time, the dimmer output signal value represents one of multiple dimming levels. In at least one embodiment, the lighting output function maps the dimmer output signal value to a dimming value different than the dimming level represented by the dimmer output signal value. The lighting output function converts a dimmer output signal values corresponding to measured light levels to perception based light levels. A light source driver operates a light source in accordance with the predetermined lighting output function. The system and method can include a filter to modify at least a set of the dimmer output signal values prior to mapping the dimmer output signal values to a new dimming level.

Lighting System with Lighting Dimmer Output Mapping

A control circuit for a switch unit of a clocked power supply receives an auxiliary signal from a resonant transformer driven by the switch unit and detects reference crossing moments when the auxiliary signal crosses a reference value. A driver is controllable to switch the switch unit, and a synchronization circuit synchronizes a turn-on of the switch unit within a predetermined time interval around a zero crossing of a voltage present across the switch unit, or of a current flowing through the switch unit. The synchronization circuit receives information about the reference crossing moments and provides a turn-on signal to the driver with a fixed phase delay at the reference crossing moments, so as to define turn-on moments at which the driver is to turn on the switch unit.

Control circuit for a switch unit of a clocked power supply circuit, and resonance converter

A circuitry comprises a converter means for generating an alternating current signal from an energy from an energy source, a piezo transformer with an input and an output, wherein the input of the piezo transformer is electrically coupled to the converter means, to receive the alternating current signal as an excitation on the input side from the converter means, and wherein the output of the piezo transformer is designed to provide an output current, and a load, which is coupled to the output of the piezo transformer, so that output current flows through the same. The load is designed to convert at least part of the electrical energy supplied by the output current flowing through the load into another form of energy. The load is further designed such that a useful power provided in the form of useful energy is substantially proportional to the output current. The circuitry is designed to adjust the output current to a predetermined value. The described circuitry allows the supply of a load with particularly high efficiency, low interference emission and good regulation characteristics.

Circuitry for supplying a load with an output current

An up to 5 Watts wide range power supply LED driver demonstrator with a piezoelectric transformer (PT) has been built to show the static and dynamic behavior as an off-line power supply The target of the power converter controller using a PT, with 23 mm thickness and 17 mm diameter at frequency of 155-175 kHz, designed in a resonant circuit of class-E topology, is to maintain a constant output current of 290 mA/DC with variable output voltage drop at wide input voltage range of 85-250 V/AC Also, the ZVS (zero-voltage-switching) condition is achieved over the full operation range The used 1200 V fieldstop IGBT (1A-Type) shows losses around 200 mW over the full operating range for constant output current The paper shows the regulation method for off-line power supplies using PT in class-E topology in constant current mode regulation (CCMR) The regulation algorithm has been programmed in C language operated by a 32-bit DSP (TMS320F2812) Besides, in the class-E application, the duty cycle of the switching frequency needs to be controlled in order to achieve the ZVS during the operation at different load and input condition This goal is achievable only by phase locked loop (PLL) feedback in a satisfying way To solve this problem, the idea of PT with an auxiliary tap has been applied The application is suited for low size LED line adapters, to be integrated in bulb sockets The results are applicable for any controller design of resonant PT step-down topologies The several suited optimum control concept is investigated in this paper, considering the circuit expense being minimized

A Line Power-Supply for LED Lighting using Piezoelectric Transformers in Class-E Topology

In a resonance converter for driving variable loads at first an input signal provided by a switch controlled by control means is converted to an output signal by a transformer. The transformer is dimensioned and connected such that a downward transformation ratio between input signal and output signal is between 5:1 and 100:1 when providing nominal power to the variable load. The switching frequency of the switch is controlled on the basis of a phase shift between a switch current and a load current at variable load and/or variable input voltage, a quantity dependent on the input voltage, as well as a quantity dependent on the output voltage. The inventive resonance converter further enables driving variable loads efficiently with the aid of a transformer.

Resonance converter with voltage regulation and method of driving variable loads

A 1 to 5 Watts wide-range power supply demonstrator with a transoner-type piezoelectric transformer (PT) has been built in class E topology to show the full functionality of an off-line power supply. A basic design target was the ZVS or near-ZVS behaviour, which was achieved for 3 Watts and 6 V output at input voltages between 85 and 260 V AC, and for 5 Watts and 6 V output at Vin = 150 to 260 V AC, respectively, using one and the same PT sample. The PT was 2.3 mm thick, and had a diameter of 17 mm. The used fieldstop-IGBT 1 A-type shows losses less than 700 mW over the full operating range for constant output voltage optimization, and less than 250 mW, for maximum efficiency optimization, respectively, at frequencies of 155 to 172 kHz. The measured overall worst case efficiency of the converter (without rectifiers) has been accordingly 70.5%, and 82.4%, respectively. The application is suited for smart-card format power supplies below 5 mm thickness. Compared to the half-bridge, the class E concept, as a current fed topology, promises better EMI suppression by the input inductor than a half-bridge, lower switch current peaks, and a larger control bandwidth at the same frequency. Further, it was demonstrated with the class E concept, that it is possible to keep the output voltage constant, using the resonant tank with the output capacitance. Thus, output charging capacitors can be made very small, compared to fly-back converters or other hard-switching conventional topologies. The measurements had been in good agreement with the differential equations analysis and the SPICE simulation, as well. These results led to current projects for mass market applications using the class E topology, and alternatively the half-bridge for higher power levels.

http://ieeexplore.ieee.org/iel5/9371/29755/01355252.pdf

Matthias Radecker

Papers

Control circuit for a switch unit of a clocked power supply circuit, and resonance converter

Circuitry for supplying a load with an output current

A Line Power-Supply for LED Lighting using Piezoelectric Transformers in Class-E Topology

Resonance converter with voltage regulation and method of driving variable loads

Comparison of resonant topologies for step-down applications using piezoelectric transformers