Abstract: An adaptive gaseous fuel ignition control method for use in consumer and commercial appliances that reduces stress on and increases the life of a hot surface igniter without resulting in a failure to ignite condition is provided. The method provides a preheating period, a full temperature period, and a trial for ignition period. The preheating period gradually increases the power applied to reduce the stress resulting therefrom. Once a gas valve has been commanded open, the controller monitors the time for ignition of the gaseous fuel. If the time is longer than a threshold, either the applied power or the period of time during which the power is applied is increased to shorten the time. If, however, the ignition period is shorter than the threshold, either the power applied or the period of time during which the power is applied before commanding the gas valve open is lowered or shortened.

Abstract: An adaptive gaseous fuel ignition control method for use in consumer and commercial appliances that reduces stress on and increases the life of a hot surface igniter without resulting in a failure to ignite condition is provided. The method provides a preheating period, a full temperature period, and a trial for ignition period. The preheating period gradually increases the power applied to reduce the stress resulting therefrom. Once a gas valve has been commanded open, the controller monitors the time for ignition of the gaseous fuel. If the time is longer than a threshold, either the applied power or the period of time during which the power is applied is increased to shorten the time. If, however, the ignition period is shorter than the threshold, either the power applied or the period of time during which the power is applied before commanding the gas valve open is lowered or shortened.

Abstract: An analog flame sense circuit is provided that utilizes the flame rectification method of sensing flame. The circuit uses an AC voltage source and discrete components to provide the sensing of the flame current. Either a single-pole or a two-pole filter may be used to smooth the generated sense voltage. A DC bias is provided to the filter to ensure a positive voltage. The circuit also includes a high-gain, high-impedance amplifier to translate the high impedance voltage of the sensing portion of the circuit to a relatively low impedance voltage for use by an electronic control circuit. In one embodiment, a high-gain emitter-follower amplifier constructed from two bi-polar junction transistors (BJTs) is used. An integrated Darlington configuration may be used, as well as a single BJT having a high gain, and an integrated operational amplifier.

Abstract: An electrosurgical generator which provides a constant power output particularly suited for cutting arc formation at an active electrode which exhibits a dynamic active surface area of varying geometry. Essentially constant power-based control is achieved through the utilization of a d.c. link voltage the level of which functions to establish the amplitude of the output of an RF resonant inverter. A dual loop feedback control is described wherein output power based control signals are slowly introduced at low gain, while link voltage based controls are comparatively rapidly applied. Enhanced development of a controlling d.c. link voltage is achieved through the utilization of an input network incorporating a power factor correction stage.

Abstract: An analog flame sense circuit is provided that utilizes the flame rectification method of sensing flame. The circuit uses an AC voltage source and discrete components to provide the sensing of the flame current. Either a single-pole or a two-pole filter may be used to smooth the generated sense voltage. A DC bias is provided to the filter to ensure a positive voltage. The circuit also includes a high-gain, high-impedance amplifier to translate the high impedance voltage of the sensing portion of the circuit to a relatively low impedance voltage for use by an electronic control circuit. In one embodiment, a high-gain emitter-follower amplifier constructed from two bi-polar junction transistors (BJTs) is used. An integrated Darlington configuration may be used, as well as a single BJT having a high gain, and an integrated operational amplifier.

Abstract: An electrosurgical generator which provides a constant voltage and variable power output particularly suited for cutting arc formation at an active electrode which exhibits a dynamic active surface area of varying geometry. Essentially constant voltage-based control is achieved through the utilization of a d.c. link voltage the level of which functions to establish the amplitude of the output of an RF resonant inverter. A dual loop feedback control is described wherein output voltage based control signals are slowly introduced at low gain, while link voltage motor-based controls are comparatively rapidly applied. Enhanced development of a controlling d.c. link voltage is achieved through the utilization of an input network incorporating a power factor correction stage.

Abstract: An electrosurgical generator which provides a constant power output particularly suited for cutting arc formation at an active electrode which exhibits a dynamic active surface area of varying geometry. Essentially constant power-based control is achieved through the utilization of a d.c. link voltage the level of which functions to establish the amplitude of the output of an RF resonant inverter. A dual loop feedback control is described wherein output power based control signals are slowly introduced at low gain, while link voltage based controls are comparatively rapidly applied. Enhanced development of a controlling d.c. link voltage is achieved through the utilization of an input network incorporating a power factor correction stage.

Abstract: System, method and apparatus for carrying out the recovery of an intact volume of tissue wherein a delivery cannula distal end is positioned in confronting adjacency with the volume of tissue to be recovered. A capture component formed of a plurality of metal leafs is deployed from the distal end of the delivery cannula. The tips of these leafs carry a pursing cable assembly which is electrically excited to electrosurgically cut around and circumscribe the tissue volume. These pursing cables are tensioned to complete the envelopment of the tissue volumes by drawing the leaf tips together. Drive to the capture component ultimately is developed from an electric motor and electrosurgical cutting current is supplied initially at a boost voltage level and thereafter at a lower normal cutting voltage level.

Abstract: A compact multiple output power supply which has a circuit architecture with distinct primary and secondary circuit domains. Within the secondary circuit domain, a distribution bus of relatively low constant voltage supplies power inputs to d.c.-to-d.c. converters providing regulated outputs and operating independently of each other. Because of the secondary circuit domain topology, surface mount components are made available in conjunction with relatively simple converter circuitry. Heat management within the compact housing of the power supply is achieved through the utilization of linear driven air flows in combination with employment of heat sinks extending to the heat sink configured cover of the housing. Additionally, the highest heat generation components are positioned rearwardmost within the driven air path.

Abstract: System, method and apparatus for carrying out the recovery of an intact volume of tissue wherein a delivery cannula distal end is positioned in confronting adjacency with the volume of tissue to be recovered. A capture component formed of a plurality of metal leafs is deployed from the distal end of the delivery cannula. The tips of these leafs carry a pursing cable assembly which is electrically excited to electrosurgically cut around and circumscribe the tissue volume. These pursing cables are tensioned to complete the envelopment of the tissue volumes by drawing the leaf tips together. Drive to the capture component ultimately is developed from an electric motor and electrosurgical cutting current is supplied initially at a boost voltage level and thereafter at a lower normal cutting voltage level.

Abstract: A compact multiple output power supply which has a circuit architecture with distinct primary and secondary circuit domains. Within the secondary circuit domain, a distribution bus of relatively low constant voltage supplies power inputs to d.c.-to-d.c. converters providing regulated outputs and operating independently of each other. Because of the secondary circuit domain topology, surface mount components are made available in conjunction with relatively simple converter circuitry. Heat management within the compact housing of the power supply is achieved through the utilization of linear driven air flows in combination with employment of heat sinks extending to the heat sink configured cover of the housing. Additionally, the highest heat generation components are positioned rearwardmost within the driven air path.

Abstract: A power supply/backplane assembly and system wherein a substantially flat power supply assembly including a printed circuit, power converter modules, and heat sink is mounted directly to the rearwardly disposed surface of a backplane. The size of the power supply and the region at which it is mounted substantially falls within the border of a fully defined region of the backplane. Flat copper traces carried by the power supply circuit board function to carry regulated power directly to the backplane via a power bolt system. Thus, conventional cabling is eliminated. The circuit board also is employed in conjunction with readily accessible connector components to provide for simplified wiring installation of support features such as the interaction between a supervisory panel and a front end a.c.-to-d.c. conversion component.

Abstract: A thin power supply is configured to be mounted vertically within a card cage for pin assembly connection with the forward face of a backplane. Through the utilization of a vertical flat metal platform in combination with a thin sheet metal folded fin array, the components of the power supply may be cooled by fan driven air of passing through the card cage itself. To achieve heat dissipation, those components of the power supply which exhibit higher heat dissipation characteristics are firmly coupled with the power supply platform such that the bulk of the heat generated by them is dissipated by the folded fin array and the card cage fan driven air passing over and through it. Other components not having high beat dissipation characteristics are circuit board mounted and cooled by the movement of fan driven card cage air flow which passes through the housing of the power supply.

Abstract: An x-ray tube of a CT scanner is powered by a high-voltage power supply (26). The high-voltage power supply includes a plurality of sections (102) each having three straight-up transformers (48) which receive three 120.degree. phase shifted alternating current components as inputs. The straight-up transformers perform a direct voltage transformation with single or multiple transformers and with no capacitive multipliers. Each straight-up transformer has a primary winding (T1) and two secondary windings (T1-A, T1-B). The secondary windings are connected together in delta and wye configurations (84). The alternating current components have their voltage boosted and are rectified and summed to form a high-voltage output that is substantially ripple-free. A pulse-width modulated converter (34) generates a conditioned output current from an inputted direct current.