12323 results about "Alternate current" patented technology

The present invention provides an apparatus and a method for producing a virtual electrode within or upon a tissue to be treated with radio frequency alternating electric current, such tissues including but not limited to liver, lung, cardiac, prostate, breast, and vascular tissues and neoplasms. An apparatus in accord with the present invention includes a supply of a conductive or electrolytic fluid to be provided to the patient, an alternating current generator, and a processor for creating, maintaining, and controlling the ablation process by the interstitial or surficial delivery of the fluid to a tissue and the delivery of electric power to the tissue via the virtual electrode. A method in accord with the present invention includes delivering a conductive fluid to a predetermined tissue ablation site for a predetermined time period, applying a predetermined power level of radio frequency current to the tissue, monitoring at least one of several parameters, and adjusting either the applied power and / or the fluid flow in response to the measured parameters.

The present invention provides an apparatus and a method for producing a virtual electrode within or upon a tissue to be treated with radio frequency alternating electric current, such tissues including but not limited to liver, lung, cardiac, prostate, breast, and vascular tissues and neoplasms. An apparatus in accord with the present invention includes a supply of a conductive or electrolytic fluid to be provided to the patient, an alternating current generator, and a processor for creating, maintaining, and controlling the ablation process by the interstitial or surficial delivery of the fluid to a tissue and the delivery of electric power to the tissue via the virtual electrode. A method in accord with the present invention includes delivering a conductive fluid to a predetermined tissue ablation site for a predetermined time period, applying a predetermined power level of radio frequency current to the tissue, monitoring at least one of several parameters, and adjusting either the applied power and / or the fluid flow in response to the measured parameters.

The invention comprises use of Dynamically Switchable Bypass (DSB) elements in association with one or more Light Emitting Diodes (LEDs) in arrays for illumination circuits to provide rugged, reliable lighting. The DSBs are selected from Transient Voltage Suppressors, including Silicon, Metal Oxide Varistors, and Multi Layer Varistors as well as Zener Diodes. The DSBs are not used as circuit protecting devices, but rather as alternative paths for electric current to bypass failed LEDs. Bi-directional TVSs are used as alternative electric paths for circuits using Alternating Current (AC) and parallel LED arrays that light on both phases of AC. Zener Diodes are used in parallel to, but in the opposite polarity orientation to, one or more LEDs in DC or rectified AC circuits. The inventive paired DSB / LED elements overcomes the black-out problems of prior series LED illumination systems, making possible the use of robust LEDs in illumination systems where reliability, long life, low power consumption, low heat output, resistance to shock, vibration, and humidity, and self-diagnosis are important. The DSB elements have breakdown voltages slightly higher than the LED(s) they support, so that when an LED fails, the conduction through the DSB begins. Because the conduction voltage of the DSB so nearly matches the conduction voltage of the LED(s), the remainder of the circuit continues to function as normal. The system is self-diagnostic in that any LED failure presents itself as a dark LED rather than as a whole string of dark LEDs. DSBs may be used with incandescent bulbs.

A novel integrated rectifier and boost converter circuit architecture is disclosed. The rectifier architecture includes a plurality of identical half-bridge rectifiers connected to receiving antennas to convert wireless AC power into DC power. The integrated rectifier may be coupled in series with a charging inductor in a boost converter. The inductor may discharge upon operation of two micro-controller-driven switching transistors using predetermined threshold and timing scheme to turn on / off. The rectifier architecture may provide high power densities, improve efficiency at larger load currents, and may be enabled in an integrated circuit with eight RF signal inputs, eight half-bridge rectifiers, and eight DC outputs ganged together as single feed into the boost converter. The rectifier circuit topology may include a comparator driven by the boost controller with a proprietary algorithm which suits control for a maximum power point tracking functionality, and an external micro-controller for additional control of the boost converter.

The present invention takes the form of a current limiting apparatus and method for limiting current flow, induced when the level of an external signal is greater than an external signal threshold signal level, in a conductive loop formed by a medical device implanted within a living organism having electrically excitable tissue. The system includes an implantable pulse generator (IPG) system having a housing, a signal generator disposed in the housing that generates an electrical signal, and at least one lead extending from the housing to convey electrical signal to the patient. To limit the induced current flow, the IPG includes current limiting componentry, an impedance increasing element, and / or alternating current blocking elements. These components provide an alternating current impedance path to the electrical ground from a lead coupled to the capacitive element. Also disclosed are techniques for reducing the effective surface area of the current inducing loop caused by the IPG system.

An improved electrosurgical instrument and method is disclosed for simplifying making incisions and other treatments using electrosurgery. The electrosurgical instrument comprises a body having more than two electrodes with at least two electrodes having alternating current power supplied to them such that they comprise a bipolar alternating current configuration and employ a means other than electrode spacing, composition, or geometry for reducing or preventing accumulation of eschar that would otherwise form a short circuit current path and interfere with obtaining a predetermined surgical effect. In one aspect, such means for reducing or preventing eschar accumulation consists of at least one other electrode having a direct current voltage between it and at least one of the two electrodes forming the alternating current bipolar configuration. In another aspect of the invention two or more pairs of alternating current electrodes comprising bipolar electrodes are powered with alternating current having a nonzero RMS voltage sufficient to at least reduce eschar accumulations on one electrode or induce electrolysis of at least one component of a medium surrounding at least one pair of bipolar electrodes. The electrodes are separated from each other using electrically insulating materials such that electric current does not flow between at least two of the bipolar alternating current electrodes unless they contact at least one other electrically conductive medium, such as patient tissue or a medium comprising at least in part a solid, liquid, gas, or ionized component that allows electric current to flow between electrodes. In the aspect where at least one electrode is powered by direct current the electrodes are configured such that electrical current does not flow between at least one of the bipolar alternating current electrodes and at least one of the direct current electrodes unless one or more media, such as patient tissue or a medium comprising at least in part a solid, liquid, gas, or ionized component that allows electric current to flow between electrodes, are contacting or adjacent to the electrodes having a direct current voltage difference between them. The assembly comprised of the electrodes and the separating insulating materials may also employ one or more means to reduce the current flowing between them that does not produce a desired predetermined surgical effect with one aspect of such means being using an outer insulating coating configured such that one or more portions of at least one of the bipolar alternating current electrodes are insulated while leaving exposed other portions of such insulated electrodes so that they are capable of being in electrical communication with tissue or at least one material in electrical communication with tissue.

LED driver circuits containing voltage reducing devices, voltage regulating devices, and voltage converting devices are disclosed as the main components to provide power to LEDs. The LED driver circuits are designed to work with a ballast, mains alternating current voltage, direct current voltage, and electromagnetic induction power. The voltage regulating devices can be a resistor in series with at least one zener diode or a voltage regulator both in parallel with and providing power to the LEDs. The LEDs can also be anti-parallel diode pairs consisting of one diode and one LED or two LEDs, or the LEDs can be anti-parallel diode string pairs consisting of diodes and LEDs or all LEDs. The LED driver circuits will be incorporated into LED replacement lamps, and in particular to LED lamps to replace fluorescent lamps for use with existing ballasts and other power sources where the ballast may be removed or bypassed.

An electromagnetic resonance non-contact power transmission device includes a transmitter including a transmitter resonance element having a mechanism for discretely or continuously varying a resonant frequency, a transmitter excitation element coupled to the transmitter resonance element by electromagnetic induction, and an alternating current source for applying an alternating current at the same frequency as the resonant frequency to the transmitter excitation element, and a plurality of receivers each including a receiver resonance element having a specific resonant frequency, a receiver excitation element coupled to the receiver resonance element by electromagnetic induction, and an output circuit for outputting an electric current induced by the receiver excitation element. Electric power is transmitted selectively from the transmitter to any of the receivers having different specific resonant frequencies by changing the resonant frequency of the transmitter.

A method and system for enhancing computer peripheral safety is provided. In accordance with various aspects of the present invention, the exemplary method and system are configured to monitor and / or isolate alternating current (A.C.) supplies with and / or from any peripheral subsystems or devices. An exemplary method and system comprises an A.C. supply, a host computer system, and a peripheral subsystem or device connected to the host computer system, such as an ultrasound imaging and / or therapy peripheral, and an isolation subsystem configured for monitoring and / or isolating the A.C. supply from the peripheral subsystem or device. In accordance with an exemplary embodiment, an isolation subsystem comprises application software and associated modules and functions that when executed continuously monitors and / or polls the host computer's hardware and / or operating system for the presence of an isolated source, such as a battery, or an unisolated power source, such as through a battery charger and / or other connection path to the A.C. main supply. In accordance with other exemplary embodiments, an isolation subsystem can comprises a wireless or other safe / isolated electrical link for connecting a patient contact device, and / or a verification link or other verification mechanisms configured between an isolation transformer and host computer to monitor or observe usage to power the host computer and peripheral subsystem.

A control is provided for controlling the operation of a climate control system, which includes a processor that is capable of receiving power from a low voltage power supply adapted to be connected to an external alternating current power source, or a second external low voltage power supply. The processor is capable of storing diagnostic information pertaining to the operating status of at least one component of the climate control system. The processor is configured to retrieve stored diagnostic information from memory pertaining to the climate control system and send the diagnostic information to the display means when the processor receives power from the external low voltage power supply and detects the absence of a connection to an external alternating current power source.

A driver circuit 3 feeds a pulse signal to an SSR 2 every half wave of alternating-current power from a commercial power source 4, and thereby separately controls the amounts of emitted light of LED groups 1x and 1y forming an LED unit 1, the LED groups 1x and 1y being connected in parallel in such a way as to point in different directions. That is, a first pulse signal for controlling the duration of light emission of the LED group 1x and a second pulse signal for controlling the duration of light emission of the LED group 1y are fed to the SSR 2 from the driver circuit 3.

A single cup pod beverage brewer is presented utilizing a pod (20) containing coffee grounds or tea leaves surrounded by filter paper. A pod holding chamber (22) consisting of a upper head (26) and a lower head (28) having an ejection disc (42). An upper head mounting frame (48) is attached to its horizontal base (50) and includes lower head rotating arms (60) attached to a first shaft (62) with a first gear motor (66) rotating the arms into a pod loading position, a pod brewing position and a pod disposal position. A second gear motor (66a) is secured to the upper head mounting frame, driving a cam (76) through a second shaft (62a) engaging the upper head to lower, seal and raise said upper head. A pod ejector solenoid (84) is disposed on the base electromechanically propelling the pod from the chamber when the lower head in the pod disposal position. An electronic control system employs a solid state direct current arrangement for control regulation and alternating current for heating system functions. An enclosure with panels and a door (90) protects moving elements and electrical controls.

A medical device assembly for cutting body tissue by means of electrotomy, includes a generator for a high frequency alternating current which can be delivered by way of a pole and an opposite pole, wherein each pole is connected to at least one respective output terminal of the generator; a gripping instrument with two gripping arms which each have at least one respective gripping surface and which are connected together in such a way that the gripping surfaces are movable towards each other, wherein the gripping surface is at least partially electrically conductive and each is individually electrically connected to a respective terminal or they are electrically connected to a common terminal for an electrical supply line; and a cutting instrument which has a handle and a cutting electrode, wherein in operation the cutting electrode is connected to a pole of the generator and both gripping surfaces are connected to the opposite pole of the generator.

An implantable medical device assembly that contains magnetic material with a saturation magnetization of at least about 0.15 Tesla and which has a direct current permeability at a static magnetic field value of 1.5 Tesla of at least 1.1. When the magnetic material and is simultaneously subjected to an alternating current electromagnetic field with a frequency of 64 megahertz and a static magnetic field of 1.5 Tesla, it has a magnetization of less than 100 electromagnetic units per cubic centimeter.

A vibration assisted needle device is disclosed for use in medical procedures such as needle aspiration biopsies. Reciprocation of the needle, such as a biopsy needle, eases the advance of the needle through tissue, penetration of the site of interest and the collection of sample at a site of interest. The device comprises a housing defining a chamber, a needle support external to the chamber for supporting a needle and a mechanism in the chamber for causing reciprocatory motion of the needle support. The needle support is preferably external to the housing. A syringe support may be connected to the housing for supporting a syringe. The reciprocatory mechanism may comprise means for converting rotational motion into reciprocating motion, such as a bearing or a rotor with a circumferential, angled groove on its surface, coupled to the needle support. The bearing or the rotor may be driven by a rotational motor, preferably located outside of the housing, or by a hydraulically driven turbine within the housing. Alternatively, the reciprocatory mechanism means may comprise a stationary solenoid and a movable solenoid for being coupled to the needle. Preferably, a second stationary solenoid is provided and the moving solenoid is between the two stationary solenoids. Energization of the stationary solenoid or solenoids by an alternating current for example, and energization of the movable solenoid by a direct current, or vice versa, attracts and repulses the movable solenoid, causing reciprocation of the needle. Methods and systems using the vibration assisted needle device are also disclosed.

The invention provides a compensation method of direct current (DC) voltage fluctuation of a photovoltaic grid-connected inverter, and the method can be used for improving the quality of the grid-connected current through compensating an input DC side secondary pulse voltage by adding a DC voltage pulse compensation module in a DC / AC (direction current / alternating current) high-frequency link, and eliminating a grid-connected current harmonic wave caused by the DC voltage pulse. The control performance of the system can be improved without adding a filter device and adding any extra appliance.

A two stage multiple output power supply device is capable of outputting programmable DC voltages onto multiple outputs. The first stage receives an AC supply voltage and outputs a DC supply voltage. The second stage includes a DC-ID controller and multiple DC-to-DC converters, each DC-to-DC converter receiving the DC supply voltage and capable of outputting a programmable DC voltage onto a conductor of a power cord to power an electrical device. For each DC-to-DC converter, the DC-ID controller receives information in an AC signal on the conductor, the information indicating the voltage and current requirements and the polarity of an electrical device connected to the power cord for that DC-to-DC converter. In response to the information, the DC-ID controller controls the DC-to-DC converter to set a magnitude, a polarity and a current limit for the programmable DC voltage that will be output by the DC-to-DC converter.

The present invention relates to providing an improved phase controlled dimming LED driver circuitry, system and a method thereof, which is configured to enable dimming intensity of light generated by a light source, said phase controlled dimming driver circuitry being connected to a phase control dimmer that provides to it a regulated alternating current (AC) signal, wherein said phase controlled dimming driver circuitry does not include a microprocessor and pulse width modulates its output current, provided to said light source, at a frequency unrelated to the AC signal frequency. Further, the phase controlled dimming driver circuitry applies amplitude modulation (AM) and pulse width modulation (PWM) substantially simultaneously to the output current provided to the light source.

A moister sensor, for measuring moister in a building without leaving visible scars to the building surface, is provided. The moister sensor includes a flexible carrier carrying an antenna for receiving EM-radiation between 9 kHz and 11 MHz and a resonant circuit including a moister reactive element. The moister reactive element includes a hygroscopic electrolyte arranged between a first and a second electrode, wherein the electrolyte in the presence of moister forms mobile ions and provides a complex impedance at least in response to the alternating voltage, which complex impedance varies with the moister content of the electrolyte.

Provided herein are methods and apparatus for stroke volume determination by bioimpedance from a patient's upper arm, or brachium, utilizing pulsations of the brachial artery contained therein. The apparatus includes two or more spaced apart alternating current flow electrodes positioned on the patient's arm proximate the brachial artery and two or more spaced apart voltage sensing electrodes positioned on the patient's arm proximate the brachial artery. The voltage sensing electrodes are positioned between the alternating current flow electrodes on the arm. An alternating current source is electrically connected to the alternating current flow electrodes and a voltmeter electrically is connected to the voltage sensing electrodes. A data input device is provided along with a processing unit in communication with the data input device, the alternating current source, alternating current flow electrodes, the voltmeter, and voltage sensing electrodes. The processing unit is capable of using data from the data input device and voltage sensing electrodes to calculate the stroke volume of the patient.

In electrically stimulating neural tissue it is important to prevent over stimulation and unbalanced stimulation which would cause damage to the neural tissue, the electrode, or both. It is critical that neural tissue in not subjected to any direct current or alternating current above a safe threshold. Further, it is important to identify defective electrodes as continued use may result in neural and further electrode damage. The present invention presents system and stimulator control mechanisms to prevent damage to neural tissue.

An electrosurgical instrument blade includes a body having more than two electrodes with at least two electrodes having alternating current power supplied to them provide a bipolar alternating current configuration and employ a means other than electrode spacing for reducing or preventing accumulation of eschar. The electrodes are separated from each other using electrically insulating materials such that electric current does not flow between at least two of the bipolar alternating current electrodes unless they contact at least one other electrically conductive medium, such as patient tissue. The conductor edge portion and insulation layer each have geometric shapes and composition to reduce or eliminate the production of smoke and eschar and reduce tissue damage. The outer profile of the insulation layer and conductive element are configured to facilitate the flow of electrosurgical decomposition products away from the conductor edge where they are formed.

The present invention provides devices and systems, as well as methods, of electric field delivery and ablation (e.g., non-thermal ablation) of target tissues, including cancerous cells and solid tumors. A method of the present invention can include applying an alternating current to a target tissue and removing ablated or liquefied tissue from the target tissue region.

An iontophoretic method for transporting compounds of interest across a body tissue is provided. The method utilizes an AC signal in conjunction with a barrier-modifying agent such as a fatty acid, fatty alcohol, bile acid, surfactant, or the like. The method enables the maintenance of a substantially constant electrical state in a localized region of the tissue through which transport occurs, thereby allowing a compound of interest to be transported across the tissue in a controlled and predictable manner. The barrier-modifying agent reduces the time as well as the voltage level required to achieve a target electrical resistance, thereby reducing patient discomfort and increasing the battery life of the iontophoresis device.

The invention discloses a green power converter which omits the pulse width modulation (PWM) technique in the traditional power converter, does not have high-frequency power device, does not generate EMI interference, simultaneously adopts the symmetry basic primitive (SBP) technique, the amplitude high modulate (AHM) technique and the dynamic rectification (DR) technique, and only needs to perform traditional power conversion on a small part of the input power so as to acquire the whole output power, namely that a large part of the output power neither need traditional power conversion nor need to pass through a magnetic core transformer. The input AC voltage neither needs to be rectified and filtered nor has large inductance and large capacitance, thus the power factor is 1, and the total harmonic distortion (THD) is 0. A transformer secondary side adopts dynamic rectification, can acquire a DC circuit, and can also acquire an AC voltage. The circuit complexity, the power consumption and the failure rate of the whole green power converter are greatly lowered, and the power converter can be applied in all the fields to replace the traditional power converter.

A retina implant including a chip adapted to be implanted into the interior of eye in subretinal contact with the retina. The chip has a plurality of pixel elements on a side thereof facing the lens for receiving an image projected into the retina and a plurality of electrodes for stimulating retina cells. The implants further includes a receiver coil for inductively coupling thereinto electromagnetic energy. The receiver coil coupled to a means for converting an alternating voltage induced into the receiver coil in a direct voltage suited for supplying the chip. The receiver coil is configured as a component separate from the chip, and for being positioned on the eye ball outside the sclera. The chip is connected to the receiver coil via a connecting lead which, in the implanted condition interconnects the interior and the exterior of the eye ball.

A method estimates morphological features of heart beats from an ECG signal. Peaks of the R wave of the ECG are detected and classified using a parallel filtering structure. The first branch implements a bandpass filtering with cut off frequencies of about 10 Hz and 35 Hz, enhancing the signal-to-noise ratio (SNR) of the QRS complex. The second branch estimates morphological features of the heart beat from an alternating current (AC) replica of the ECG signal, that may be used to classify the beat and potentially detect arrhythmias.