Abstract: Apparatus for use with a medical implant having a receiving coil. A flexible housing to be placed against skin of a subject includes a flexible transmitting coil and control circuitry for driving a current through the transmitting coil to induce a current in the receiving coil. A sensor coupled to the circuitry determines divergence of a resonance frequency of the transmitting coil when flexed from a nominal resonance frequency of the transmitting coil, occurring in the absence of any forces applied to the transmitting coil. One or more electrical components coupled to the circuitry tune the resonance frequency of the transmitting coil. A switch is coupled to each of the electrical components, the switches including transistors having capacitances that depend on the voltage applied to each switch. The circuitry applies a respective DC voltage to each switch. Other applications are also described.

Abstract: A housing placeable against skin of a subject includes a transmitting coil. Battery-powered control circuitry including a power stage transmits power to an implant by activating the power stage to drive a current through the transmitting coil to induce an induced current in a receiving coil of the implant. A sensor indicates divergence of a real-time resonance frequency of the transmitting coil with respect to a reference resonance frequency of the transmitting coil at which (a) efficiency of the power stage is at least 70% of a maximum efficiency as a function of the resonance frequency, and (b) the current driven through the transmitting coil is less than 960 of a maximum current drivable through the transmitting coil as a function of the resonance frequency. The circuitry reduces the divergence by tuning the resonance frequency of the transmitting coil. Other applications are also described.

Abstract: Power is transmitted to an implanted receiving coil oriented such that an axis of the receiving coil is parallel to skin of a subject. A transmitting coil is in a housing, which is placed against the skin. A central axis of the transmitting coil is perpendicular to the skin. A portion of the transmitting coil is over the receiving coil. A first distance, from the axis of the transmitting coil to a center of the receiving coil, is greater than a second distance, from the axis of the transmitting coil to an inner edge of the portion of the transmitting coil. The first distance is less than a third distance, from the axis of the transmitting coil to an outer edge of the portion of the transmitting coil. Circuitry powers the implant by driving current through the transmitting coil that induces current in the receiving coil.

Abstract: Apparatus for use with a medical implant having a receiving coil. A flexible housing to be placed against skin of a subject includes a flexible transmitting coil and control circuitry for driving a current through the transmitting coil to induce a current in the receiving coil. A sensor coupled to the circuitry determines divergence of a resonance frequency of the transmitting coil when flexed from a nominal resonance frequency of the transmitting coil, occurring in the absence of any forces applied to the transmitting coil. One or more electrical components coupled to the circuitry tune the resonance frequency of the transmitting coil. A switch is coupled to each of the electrical components, the switches including transistors having capacitances that depend on the voltage applied to each switch. The circuitry applies a respective DC voltage to each switch. Other applications are also described.

Abstract: Apparatus is provided for use with a medical implant having a receiving coil. A flexible housing to be placed against skin of a subject includes a flexible transmitting coil and control circuitry for driving a current through the transmitting coil to induce a current in the receiving coil. A sensor coupled to the circuitry determines divergence of a resonance frequency of the transmitting coil when flexed from a nominal resonance frequency of the transmitting coil, occurring in the absence of any forces applied to the transmitting coil. One or more electrical components coupled to the circuitry tune the resonance frequency of the transmitting coil. A switch is coupled to each of the electrical components, the switches including transistors having capacitances that depend on the voltage applied to each switch. The circuitry applies a voltage of 30-300 volts to each switch. Other applications are also described.

Abstract: Power is transmitted to an implanted receiving coil oriented such that an axis of the receiving coil is parallel to skin of a subject. A transmitting coil is in a housing, which is placed against the skin. A central axis of the transmitting coil is perpendicular to the skin. A portion of the transmitting coil is over the receiving coil. A first distance, from the axis of the transmitting coil to a center of the receiving coil, is greater than a second distance, from the axis of the transmitting coil to an inner edge of the portion of the transmitting coil. The first distance is less than a third distance, from the axis of the transmitting coil to an outer edge of the portion of the transmitting coil. Circuitry powers the implant by driving current through the transmitting coil that induces current in the receiving coil.

Abstract: Power is transmitted to an implanted receiving coil oriented such that an axis of the receiving coil is parallel to skin of a subject. A transmitting coil is in a housing, which is placed against the skin. A central axis of the transmitting coil is perpendicular to the skin. A portion of the transmitting coil is over the receiving coil. A first distance, from the axis of the transmitting coil to a center of the receiving coil, is greater than a second distance, from the axis of the transmitting coil to an inner edge of the portion of the transmitting coil. The first distance is less than a third distance, from the axis of the transmitting coil to an outer edge of the portion of the transmitting coil. Circuitry powers the implant by driving current through the transmitting coil that induces current is the receiving coil.

Abstract: The present invention provides systems and methods for automatic dimmer loading in a cut-phase dimmer-converter arrangement, the method including providing minimum dimmer hold-on current by continuously loading of the dimmer with the current grater than minimum hold-on dimmer current without current measurement means or with using of measurement means by measuring a first current across the dimmer to form a current output signal and compensating for a drop in the dimmer output current by adding a load current across said dimmer to ensure that a total current comprising a sum of the first current and the load current always exceeds a threshold current for continuous operation of the dimmer.

Abstract: An adaptive loader for time varying, non-linear high-impedance power sources (HIS) comprising: an electronic converter, matching the impedance of said HIS to its load; at least one sensor; and a control system, controlling loading factor of the electronic converter to ensures impedance matching between said time varying HIS and its load. The loader may be used for any HIS like piezoelectric, photoelectric, thermoelectric, etc., sources. Impedance matching can be used for energy production, measurement of the input stimuli or both of them. The load may be any active or capacitive load including for example rechargeable battery. A piezoelectric generator producing time varying electrical signal in response to time varying mechanical strain can be used as HIS. For example the piezoelectric generator generates a pulse in response to a mechanical strain caused for example by one of passage of a vehicle or passage of a train.

Abstract: A method for reducing acoustic noise produced during use of a lamp dimmer detects whether the dimmer is a leading edge (101) or a trailing edge dimmer (102). A nominal firing time of a leading edge dimmer is determined and a post-correction applied to a voltage applied to the dimmer starting from the nominal firing time so as to build-up the voltage gradually during a predetermined post-correction time period and thereby reduce the rate of rise of the leading edge thereof. A nominal cutoff time of a trailing edge dimmer is determined and a pre-correction applied to a voltage applied to the dimmer starting from the nominal cut-off time so as to diminish the voltage gradually during a predetermined pre-correction time period and thereby reduce the rate of rise of the leading edge thereof. Other methods are disclosed for soft starting filament lamps and controlling dimmer circuits.

Abstract: A method for reducing acoustic noise produced during use of a lamp dimmer detects whether the dimmer is a leading edge (101) or a trailing edge dimmer (102). A nominal firing time of a leading edge dimmer is determined and a post-correction applied to a voltage applied to the dimmer starting from the nominal firing time so as to build-up the voltage gradually during a predetermined post-correction time period and thereby reduce the rate of rise of the leading edge thereof. A nominal cutoff time of a trailing edge dimmer is determined and a pre-correction applied to a voltage applied to the dimmer starting from the nominal cut-off time so as to diminish the voltage gradually during a predetermined pre-correction time period and thereby reduce the rate of rise of the leading edge thereof. Other methods are disclosed for soft starting filament lamps and controlling dimmer circuits.