7628 results about "Power level" patented technology

Methods for heating tissue completely, thoroughly, and uniformly comprise delivering radio frequency energy through a bipolar surgical instrument having first and second jaws with first and second electrode members within the treatment region. Tissue is grasped between the first and second jaws of the bipolar instrument. The electrode members are energized at a power level to deliver electrical energy to and heat tissue between the first and second electrode members. The power level is increased at a predetermined rate from an initial level. The initial level and predetermined rate are selected to avoid creating a vapor layer and to permit an impedance increase to occur as a result of complete tissue desiccation. A tissue impedance may also be measured and compared to a preset impedance limit for terminating the power delivery when the measured impedance exceeds the impedance limit.

A method and apparatus for carrying our thermal ablation of target tissue is disclosed. The apparatus includes an RF ablation device having a multi-electrode electrode assembly designed to be deployed in target tissue, defining a selected-volume tissue region to be ablated, and having infusion channels for infusing a liquid into the target tissue during the ablation process. A control unit in the apparatus is operably connected to an RF energy source, for controlling the RF power level supplied to the electrodes, and to an infusion device, for controlling the rate of infusion of a liquid through the device into the tissue. During both electrode deployment and tissue ablation, impedance and or temperature measurements made within the tissue are used to control the RF source and infusion device, for optimizing the time and extent of tissue ablation.

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.

A silicon-on-insulator (SOI) RF switch adapted for improved power handling capability using a reduced number of transistors is described. In one embodiment, an RF switch includes pairs of switching and shunting stacked transistor groupings to selectively couple RF signals between a plurality of input / output nodes and a common RF node. The switching and shunting stacked transistor groupings comprise one or more MOSFET transistors connected together in a “stacked” or serial configuration. In one embodiment, the transistor groupings are “symmetrically” stacked in the RF switch (i.e., the transistor groupings all comprise an identical number of transistors). In another embodiment, the transistor groupings are “asymmetrically” stacked in the RF switch (i.e., at least one transistor grouping comprises a number of transistors that is unequal to the number of transistors comprising at least one other transistor grouping). The stacked configuration of the transistor groupings enable the RF switch to withstand RF signals of varying and increased power levels. The asymmetrically stacked transistor grouping RF switch facilitates area-efficient implementation of the RF switch in an integrated circuit. Maximum input and output signal power levels can be withstood using a reduced number of stacked transistors.

The present invention provides for a method and apparatus for reducing interference associated with wireless communication in an area having sensitive electronic equipment. A wireless communications device receives, from an access point, a signal having a signal strength above a predetermined threshold. The wireless communications device determines a transmission power level maximum based on the received signal and then transmits a signal to the access point at a transmission power level at or below the transmission power level maximum. The wireless communications device disables the transmission when the signal strength falls below the predetermined threshold.

A control system for managing power supplied to a phacoemulsification hand piece includes a power source that provides power to the hand piece and a controller that controls the power source. The controller calculates a thermal value based on irrigation fluid flow and a power level and decreases the power level in proportion to the calculated thermal value when the calculated thermal value exceeds a threshold thermal value. Irrigation fluid flow can be calculated from irrigation fluid pressure.