16906 results about "Duty cycle" patented technology

An electrosurgical system has an electrosurgical generator and a bipolar electrosurgical instrument, the generator being arranged to perform a treatment cycle in which radio frequency energy is delivered to the instrument as an amplitude-modulated radio frequency power signal in the form of a succession of pulses characterized by periods of a least 100 milliseconds between successive pulses and by a predetermined pulse mark-to-space ratio. Energy delivery between pulses is substantially zero and the mark-to-space ratio is typically 1:4 or less. Each burst is of sufficiently high power to form vapor bubbles within tissue being treated and the time between successive pulses is sufficiently long to permit condensation of the vapor. The treatment cycles may each include an initial period and a subsequent period, the pulse duty cycle being increased or energy being delivered continuously in the subsequent period in order that tissue coagulation can be achieved quickly despite increasing tissue impedance.

A method of controlling a motorized window treatment provides for continued operation of the motorized window treatment during an overload or low-line condition. The motorized window treatment is driven by an electronic drive unit having a motor, a motor drive circuit, and a controller. The controller controls the motor drive circuit to drive the motor with a pulse-width modulated signal generated from a bus voltage. The controller is operable to monitor the magnitude of the bus voltage. If the bus voltage drops below a first voltage threshold, the controller stops the motor or reduces the duty cycle of the pulse-width modulated signal to allow the bus voltage to increase to an acceptable magnitude. When the bus voltage rises above a second voltage threshold, the controller begins driving the motor normally once again. During an overload or low-line condition, the controller is prevented from resetting, while driving the motor with minimal interruption to the movement of the motorized window treatment.

A pulse oximeter adaptively samples an input signal from a sensor in order to reduce power consumption in the absence of overriding conditions. Various sampling mechanisms may be used individually or in combination, including reducing the duty cycle of a drive current to a sensor emitter, intermittently powering-down a front-end interface to a sensor detector, or increasing the time shift between processed data blocks. Both internal parameters and output parameters may be monitored to trigger or override a reduced power consumption state. In this manner, a pulse oximeter can lower power consumption without sacrificing performance during, for example, high noise conditions or oxygen desaturations.

A high-speed surgical handpiece (10) suitable for vitreoretinal surgery having a cutter (42) and actuators (36). The cutter (42) is a guillotine-type cutter activated by an array of leveraged piezoelectric actuators (30) that receive a driving signal from a driving controller. The controller can have control and display units with a plurality of input mechanisms receiving input from a user who selects a desired cutting rate and frequency for the cutter. The control unit produces a piezoelectric actuator output signal based on the inputs received. Fast cutting rates with reduced duty cycle as well as a proportional mode of operation are available, allowing slow controlled cutting action, for example proportional to depression of a foot-pedal (74). Low degrees of vibration and noise generation are produced.

Coexistence gaps may permit one radio access technology (RAT) to coexists with another RAT by providing period in which one RAT may be silent and another may transmit. Methods may account for the RAT traffic and for the presence of other secondary users in a channel. Methods may be provided to dynamically change the parameters of a coexistence gap pattern, such as the duty cycle, to adapt to both the RAT traffic and the presence of other secondary users. Methods may include PHY methods, such as synchronization signal (PSS / SSS) based, MIB based, and PDCCH based, MAC CE based methods, and RRC Methods. Measurements may be provided to detect the presence of secondary users, and may include reporting of interference measured during ON and OFF durations, and detection of secondary users based on interference and RSRP / RSRQ measurements.

Under a control by a controller (14), a rechargeable electric device makes a full charge display to display on a display unit (15) that a secondary battery (11) is fully charged, after a start of charging the secondary battery (11) in a case where either when a count value of a counter reaches a first predetermined value (C1) corresponding to the full charge of the secondary battery (11), or when a duty ratio of switching signals which make an on / off control of a switching element (131) becomes smaller than or equal to a predetermined value (D) corresponding to the charge current obtained at a time of the full charge of the secondary battery (11).

The system periodically measures the battery voltage of the toothbrush and the current in a stator portion of the motor for the appliance. The amplitude of movement of the toothbrush workpiece is determined from the measured stator current. A circuit / control program changes the duty cycle or pulse width of the drive signal from the motor if the battery voltage drops below a first threshold value and a circuit or control program changes the drive frequency of the appliance if the amplitude of the workpiece movement falls below a first threshold value. A circuit / control program terminates the operation of the toothbrush if the voltage drops below a second threshold value or if the amplitude drops below a second threshold value, both of which are less than the respective first thresholds.

An exemplary embodiment provides a current regulator for controlling variable brightness levels for solid state lighting. The current regulator is couplable to a phase-modulating switch, such as a dimmer switch, which is coupled to an AC line voltage. An exemplary current regulator includes a rectifier; a switching power supply providing a first current; an impedance matching circuit; and a controller. The impedance matching circuit is adapted to provide a second current through the phase-modulating switch when a magnitude of the first current is below a first predetermined threshold, such as a holding current of a triac of the phase-modulating switch. The controller is adapted to determine a root-mean-square (RMS) voltage level provided by the phase-modulating switch from the AC line voltage and to determine a duty cycle for pulse-width current modulation by the switching power supply in response to the comparison of the RMS voltage level to a nominal voltage level.

Described herein are improved configurations for a wireless power transfer. The parameters of components of the wireless energy transfer system are adjusted to control the power delivered to the load at the device. The power output of the source amplifier is controlled to maintain a substantially 50% duty cycle at the rectifier of the device.

A method for the treatment of obesity or other disorders by electrical activation or inhibition of nerves is disclosed. This activation or inhibition can be accomplished by stimulating a nerve using an electrode. Dynamic stimulation through ramped cycling of electrical stimulation, stimulation frequency alteration, and / or duty cycle variance can produce therapeutic benefits.

An impact tool includes: a motor; a trigger; a controller configured to control driving power supplied to the motor using a semiconductor switching element according to an operation of the trigger; a striking mechanism configured to drive a tip tool continuously or intermittently by rotation force of the motor, the striking mechanism including a hammer and an anvil. The controller drives the semiconductor switching element at a high duty ratio when the trigger is manipulated. The motor is driven so that the duty ratio is lowered before a first striking of the hammer on the anvil is performed and the first striking is performed at a low duty ratio lower than the high duty ratio.

A light emitting diode (LED) lighting system includes a controller to control current in one or more LEDs in response to a dimming level input. The LED lighting system implements a dimming strategy having two modes of operation that allow the LED lighting system to dim the LEDs using an active value of an LED current less than a full value LED current while maintaining continuous conduction mode operation. In an active value varying mode of operation, the controller varies an active value of the LED current for a first set of dimming levels. In an active value, duty cycle modulation mode of operation, the controller duty cycle modulates an active value of the LED current for a second set of dimming levels. In at least one embodiment, the active value of the LED current varies from a full active value to an intermediate active value as dimming levels decrease.

The present invention provides for systems and methods for dimming a LED matrix functioning as a backlight to an avionics display. A system according to an embodiment of the present invention comprises a processor for receiving inputs of ambient lighting and temperature, as well as light generated by the LED matrix. The processor provides modulated pulse wave signals (square waves) to two control circuits for controlling the LED matrix in two modes. At low dimming levels, the processor modulates the duty cycle of a first square wave for affecting the light level and maintains a minimal duty cycle of a second square wave. Once the highest light level is obtained by increasing the duty cycle of the first square wave, the processor then modulates a second square wave by increasing its duty cycle. The duty cycle of the second square wave is modified by a circuit to produce a voltage level which is provided as an input to control light level of the LED matrix. As the duty cycle of the second signal is increased, so is the voltage level provided to the LED matrix and the light generated by the LED matrix.

A drive unit being characterized in that a movable object can be prevented from being tilted when the movable object is stopped using a restricting member. The drive unit comprises a piezoelectric element, a rod provided at an end of the piezoelectric element, a movable object frictionally engaged with the rod, and drive pulse generating means that apply drive signals to the piezoelectric element. The drive pulse generating means apply to the piezoelectric element a rectangular wave drive signal that has a duty ratio other than 0.5 and vibrates the rod so that a difference occurs between the expansion and contraction of the rod when the movable object is moved, and apply to the piezoelectric element a rectangular wave drive signal that has a duty ratio of 0.5 and vibrates the rod so that the movable object is not moved substantially when it is detected that the movable object is in contact with a restricting member.

An apparatus, method and system are provided for power conversion to supply power to a load such as a plurality of light emitting diodes. An exemplary apparatus comprises: a first power converter stage having a first power switch and a first inductive element; a second power converter stage having a second power switch and a second inductive element; a plurality of sensors; and a controller. The second power converter stage provides an output current to the load. The controller is adapted to use a sensed input voltage to determine a switching period, and is further adapted to turn the first and second power switches into an on-state at a frequency substantially corresponding to the switching period while maintaining a switching duty cycle within a predetermined range.

A hierarchical 3D graphics model can be viewed as a hierarchical graph of its nodes and their associated motions, with the mathematical type of motions graphically indicated. A user can click on a displayed motion to edit it. A motion API provides one or more of the following features: (1) spatial predicate functions; (2) functions for scaling motion intensity; (3) classes for shake, spin, and swing motions; (4) motion classes with a GUI interfaced for defining their duty cycle; (5) functions for defining and computing 0through 2<nd >order derivatives of 3D position and orientation as function of time; (6) behaviors that constrain motions by boundaries in which the constraint is a reflection, clamp, andor onto constraint, or in which the boundary is a composite boundary. Motions can be defined by successive calls to an API and then be saved in a file.

A lighting control circuit comprises a dimming level detection circuit, a waveform generator and a comparator circuit. The dimming level detection circuit is configurable to generate a first voltage level signal corresponding to a selected one of at least two different types of dimming signals selected from among an AC phase cut dimming signal, a DC voltage level dimming signal or a PWM dimming signal. The waveform generator is configured to output a periodic waveform. The comparator circuit is configured to compare the periodic waveform with the first voltage level signal to generate an output waveform having a duty cycle corresponding to a dimming level of the one of the at least two different input dimming signals and a frequency corresponding to the frequency of the periodic waveform. Also, methods of controlling lighting.

An electrosurgical system is provided that includes an electrosurgical generator; and an electrosurgical pencil selectively connectable to the electrosurgical generator. The electrosurgical pencil includes an elongated housing; at least one electrocautery end effector removably supportable within the housing and extending distally from the housing, the electrocautery end effector being connected to the electrosurgical generator; and at least one voltage divider network supported on the housing. The at least one voltage divider network is electrically connected to the electrosurgical generator and controls at least one of the intensity of electrosurgical energy being delivered to the electrosurgical pencil and the mode of electrosurgical energy being delivered to the electrosurgical pencil. The voltage divider network generates a plurality of characteristic voltages which are measurable by the electrosurgical generator and which electrosurgical generator in turn transmits a corresponding waveform duty cycle at a particular intensity to the electrocautery end effector of the electrosurgical pencil.

A LED driver is connectible to several series connected RGB LEDs which connect in series with a current generator. A plurality of LED switches are respectively connectible across one RGB LED. Each LED switch, operating in response to a binary signal is either open to permit electrical current to flow through the RGB LED, or closed to shunt current around that RGB LED. By varying respective duty cycles of the binary signals the LED driver is adapted for controlling operation of the combined RGB LEDs so they emit differing colors of light. An adaptive boost converter LED driver continuously adjusts voltage applied across the series connected RGB LEDs to be only that required for operating those LEDs through which open LED switches permit current to flow.

A single-inductor dual-output buck converter and control method that facilitates power conversion by converting a single DC power source / supply into two separate DC outputs, each of which can be configured to provide a selected / desired voltage by selection of respective duty cycles. The topology of the inverter includes a pair of diodes or switches that can selectively re-circulate inductor current. The converter is generally operated at a fixed frequency with four stages of operation. A first and third stage of operation provide power to a first and second output, respectively. A second and fourth stage of operation re-circulate inductor current and can partially recharge a battery type power source. The power output for each stage (voltage and current) can be selectively obtained by computing and employing appropriate time periods for the stages of operation that correspond to appropriate duty cycles.

A medical device system and method provide an RF electrosurgical generator coupled to an electrosurgical electrode via a patient box disposed in close proximity to the patient. An RF signal is delivered from the generator to the patient box where signal power is increased and the RF signal delivered to the electrosurgical electrode. The patient box is coupled to the electrosurgical electrode by a short cable capable of carrying an HV, high frequency 5 MHz signal without leakage. An electrical characteristic associated with the electrosurgical electrode is monitored and a desired RF power output and duty cycle maintained by adjusting DC input voltage applied to an RF amplifier, responsive to the monitoring. The system determines when the electrosurgical cutting electrode has started cutting and switches from a start mode to a run mode having a different RF duty cycle and a reduced RF power output controlled by a servo system.

A method and apparatus is provided for a multiple light-source illuminating device, the design and construction of which is derived from the lighting requirements of a specific lighting application. The resulting illuminating device (16) provides illumination according to the principles of lighting practice for the optimal performance of visual tasks. Coupling with sensors (21) and logical control (20) allows illumination intensity and spectrum to be varied according to changing user needs. The illuminating device includes multiple discrete light emitting components of different spatial intensity distribution and color spectrum mounted in specific orientations such that the application oriented combined lighting effect is created. The control is provided via a differentiated power supply (19) capable of affecting the current, voltage and duty cycle determining the relative contribution of each light source effecting a different spatial intensity distribution and color spectrum.

A method and apparatus for depositing a low dielectric constant film by reaction of an organosilane or organosiloxane compound and an oxidizing gas at a low RF power level from 10-250 W. The oxidized organosilane or organosiloxane film has good barrier properties for use as a liner or cap layer adjacent other dielectric layers. The oxidized organosilane or organosiloxane film may also be used as an etch stop or an intermetal dielectric layer for fabricating dual damascene structures. The oxidized organosilane or organosiloxane films also provide excellent adhesion between different dielectric layers. A preferred oxidized organosilane film is produced by reaction of methylsilane, CH3SiH3, or dimethylsilane, (CH3)2SiH2, and nitrous oxide, N2O, at an RF power level from about 10 to 200 W or a pulsed RF power level from about 20 to 250 W during 10-30% of the duty cycle.

Described herein are improved configurations for a wireless power transfer. A power source for driving a resonator includes a switching amplifier. The duty cycle of the switching amplifier may be adjusted as well as optionally inductors and / or capacitors of the circuit to improve the efficiency of power transfer from the power source to the resonators when the parameters of the resonant load change.

Methods for cooling process chamber components are provided herein. In some embodiments, a method of cooling a process chamber component may include reducing a power provided to a heater disposed proximate a surface of the process chamber component to reduce an amount of heat provided to the component by the heater; providing a coolant to coolant channels disposed within the process chamber component using a pulsed flow having a duty cycle until the process chamber component reaches a temperature that is less than or equal to a predetermined magnitude above a temperature of the coolant; and after the process chamber component reaches the temperature less than or equal to the predetermined magnitude above a temperature of the coolant, reducing the duty cycle of the pulsed flow of the coolant to zero.

An adaptive switch mode LED driver provides an intelligent approach to driving multiple strings of LEDs. The LED driver determines an optimal current level for each LED channel from a limited set of allowed currents. The LDO driver then determines a PWM duty cycle for driving the LEDs in each LED channel to provide precise brightness control over the LED channels. Beneficially, the LED driver minimizes the power dissipation in the LDO circuits driving each LED string, while also ensuring that the currents in each LED string are maintained within a limited range. A sample and hold LDO allows PWM control over extreme duty cycles with very fast dynamic response. Furthermore, fault protection circuitry ensures fault-free startup and operation of the LED driver.

Reliability enhanced systems are shown where an short-lived electrolytic capacitor can be replaced by a much smaller, perhaps film type, longer-lived capacitor to be implemented in circuits for power factor correction, solar power conversion, or otherwise to achieve DC voltage smoothing with circuitry that has solar photovoltaic source (1) a DC photovoltaic input (2) internal to a device (3) and uses an enhanced DC-DC power converter (4) to provide a smoothed DC output (6) with capacitor substitution circuitry (14) that may include interim signal circuitry (28) that creates a large voltage variation for a replaced capacitor (16). Switchmode designs may include first and second switch elements (17) and (18) and an alternative path controller (21) that operates a boost controller (22) and a buck controller (23) perhaps with a switch duty cycle controller (32).

The invention relates to pulsed oximeters used to measure blood oxygenation. The current trend towards mobile oximeters has brought the problem of how to minimize power consumption without compromising on the performance of the device. To tackle this problem, the present invention provides a method for controlling optical power in a pulse oximeter. The signal-to-noise ratio of the received baseband signal is monitored, and the duty cycle of the driving pulses is controlled in dependence on the monitored signal-to-noise ratio, preferably so that the optical power is minimized within the confines of a predetermined lower threshold set for the signal-to-noise ratio. In this way the optical power is made dependent on the perfusion level of the subject, whereby the power can be controlled to a level which does not exceed that needed for the subject.