1702 results about "Duty cycling" patented technology

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.

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.

A buck-boost switching regulator includes two buck switches and two boost switches. Two ramp voltages VY and VY are generated. The voltage VY is compared to a voltage VEA1 that is proportional to the output of the switching regulator. This defines the duty cycle of the two buck switches. The voltage VX is compared to a voltage VEA2 that is inversely proportional to the output of the switching regulator. This defines the duty cycle of the two boost switches. The regulator seamlessly transitions between Buck, Boost and Buck-Boost modes depending on input and output conditions.

Methods and apparatus are provided for determining the duty cycle, average amperage, and / or the number of arc starts during a welding operation. The apparatus comprises first and second circuits, the first circuit being a CPU control circuit, and the second circuit being an arc time sensor circuit which is programmed to measure amperage, welding wire feed speed and preferably gas flow rates while welding. A ratio of the cumulative welding time during the audit to the total on-time provides a measurement of the efficiency of the welding arc. The welding deposition efficiency may then be calculated using the average amperage and welding duty cycle as measured and calculated by the apparatus. The number of arc starts where the arc on-time is in excess of one second may also provide a useable measurement in giving secondary information on the overall efficiency of the welding operation.

A ripple-mode controller provides reliable operation in multi-phase power supply circuits, over a variety of operating conditions. Cross-phase blanking allows the controller to preserve the desired phase relationship between the switching pulses its provides to the different output phases, and permits the controller to operate each output phase at nearly 100% duty cycles. Active current sharing compliments blanking operations by adjusting the width of switching pulses the controller provides to one or more of the output phases based on detecting load current imbalances between the different output phases. With active current sharing, the controller prevents one or more output phases from carrying excessive portions of the load current. Further complimenting its operation, the controller may include virtual ripple generation to increase the noise immunity of its ripple-mode regulation.

A method for reducing the harmonics contents of an input current drawn from a power line into an electrical system without sensing an input voltage, the method comprising providing an active power factor correction controller with a switch module having a main switch and a timing device, wherein the main switch has an on-time correlated with an on-duty cycle duration, and an off-time correlated with an off-duty cycle duration, and maintaining a linear relationship between the off-duty cycle duration and the input current by using the timing device; and an apparatus for active power factor correction with minimum input current distortion, comprising an active power factor correction assembly that includes a main switch and a timing device, wherein the main switch has associated therewith an on-time correlated with an on-duty cycle duration, and an off-time correlated with an off-duty cycle duration, and wherein the timing device generates the mentioned on-time and off-time, and linearization means for maintaining a linear relation between the off-duty cycle duration and the input current.

An implantable drug delivery device is provided with a passive flow control device is provided in the form of a valve which may assume two flow states. Flow control is achieved by duty cycling the valve using a control module which generates appropriate signals in response to an input telemetry signal corresponding to a desired flow rate. In another embodiment, a passively controlled bolus delivery device is provided to deliver a bolus of drug in addition to normal dosage.

A device for heating or cooling a body of a user is provided. The device includes a thermoelectric module, a heat sink thermally coupled to the thermoelectric module, a wetting material in thermal communication with the heat sink, and a controller for cycling the thermoelectric module in accordance with a duty cycle. Additionally, a method of heating or cooling a portion of a body of a user is provided. The method includes cycling electrical power to a thermoelectric module at a duty cycle, transferring heat from the thermoelectric module to a heat sink, and evaporating a liquid from a wetting material disposed on the heat sink. The evaporated liquid enters the surrounding atmosphere.

A method is presented for enabling radio-frequency (RF) communications between an implantable medical device and an external device in a manner which reduces the power requirements of the implantable device by duty cycling its RF circuitry. A wakeup scheme for the implantable device is provided in which the external device transmits a data segment containing a repeating sequence of special wakeup characters and a device ID in order to establish a communications session with the implantable device. The wakeup scheme may be designed to operate using multiple communications channels.

Electronic circuits and methods include provisions for passing a first current through a diode during a first time interval and for passing a second different current through the diode during a second different time interval. The first current is selected to achieve a predetermined voltage at a node of the diode. A duty cycle of the first current relative to the second current is selected to achieve a predetermined average current passing through the diode. In some arrangements, the diode is a light emitting diode.

A duty cycle controller apparatus for producing a duty cycle signal for controlling switching of switches of a battery charger having an AC input for receiving power and an output for supplying power to charge a battery in response to switching of the switches, while maintaining a high power factor at the AC input. The duty cycle controller apparatus includes a current command signal generator having a plurality of signal inputs for receiving a plurality of signals representing a plurality of operating conditions of the charger, a plurality of current command outputs and a processor operably configured to generate a plurality of current command signals at the current command outputs in response to respective sets of operating conditions.

A two-stage power converter that dynamically adjusts to output current requirements includes a first stage regulator that provides power to a second stage regulator. The first stage can be a buck converter, and the second stage can be a multiple-phase buck converter. The output voltage of the first stage (intermediate bus voltage Vbus) is varied according to the load current to optimize conversion efficiency. To provide maximum efficiency, the Vbus voltage is increased as load current increases. The Vbus voltage provided by the first stage can be varied by duty cycle or operating frequency control. In another embodiment, the switching frequency of the second stage is varied as output current changes so that output current ripple is held constant. In an embodiment employing a multiple-phase buck converter in the second stage, the number of operating phases are varied as output current changes.

A fixing device includes a fuser member, a heater, a thermometer, and a power supply controller. The fuser member is subjected to heating. The heater is adjacent to the fuser member to heat the fuser member. The thermometer is adjacent to the fuser member to detect an operational temperature of the fuser member. The power supply controller controls power supply to the heater by adjusting a duty cycle. The controller includes a duty cycle calculator, a driver circuit, and a duty cycle modifier. The duty cycle calculator is operatively connected to the thermometer to calculate a primary value of the duty cycle based on the operational temperature. The driver circuit is operatively connected to the duty cycle calculator to supply power to the heater according to the duty cycle. The duty cycle modifier is connected between the duty cycle calculator and the driver circuit to modify the duty cycle.

Methods and systems for reducing compensation of the body to therapy delivered by an implanted medical device are described herein. The disclosed techniques cause a change from one therapy protocol to another therapy protocol based on the occurrence of an event (e.g., time, user activations of a sensor, input from a physiological sensor, etc.). The therapy protocols of the implanted medical device differ in terms of the on-time and off-time, but effectuate the same or similar duty cycle.

A kitchen appliance for preparing yogurt, soft frozen yogurt and ice cream, hard frozen yogurt and ice cream, and cheese. The appliance includes a housing having a base and side walls defining an open top. A motor-driven paddle device is rotationally journaled with respect to the cover and base and the motor therefor is adapted to be driven either continuously or with a predetermined duty cycle, dependent upon the product being made. Also mounted on either the cover or the base is a vent hole occluder that is normally positioned to block the vent holes in the cover or base, but which shifts to a second position uncovering those vent holes when the consistency of the product being produced, as tested by the paddle motion or other apparatus reveals that a predetermined cultured state has been reached. Shifting of the occluding device from the covering position to the open position also actuates a switch to shut off the drive motor and a warming element. When a frozen yogurt product is desired, a pre-chilled freezing bowl can be placed in the housing and the paddle used to scrape the frozen yogurt from the walls of the freezing bowl.

A method for reducing the harmonics contents of an input current drawn from a power line into an electrical system without sensing an input voltage, the method comprising providing an active power factor correction controller with a switch module having a main switch and a timing device, wherein the main switch has an on-time correlated with an on-duty cycle duration, and an off-time correlated with an off-duty cycle duration, and maintaining a linear relationship between the off-duty cycle duration and the input current by using the timing device; and an apparatus for active power factor correction with minimum input current distortion, comprising an active power factor correction assembly that includes a main switch and a timing device, wherein the main switch has associated therewith an on-time correlated with an on-duty cycle duration, and an off-time correlated with an off-duty cycle duration, and wherein the timing device generates the mentioned on-time and off-time, and linearization means for maintaining a linear relation between the off-duty cycle duration and the input current.

Apparatus are provided for motor control systems and related medical devices. In one embodiment, a control system includes a motor having a rotor, a sensor to obtain a measured displacement that is influenced by rotation of the rotor, and a control module coupled to the sensor. The control module adjusts a duty cycle for a modulated voltage applied to the motor in response to a difference between an expected displacement and the measured displacement. The expected displacement is influenced by or otherwise corresponds to a commanded rotation of the rotor.

An apparatus and method for selectively cooling a gas turbine engine component for the purpose of controlling blade tip clearance during transient conditions, wherein cooling air is admitted intermittently according to a desired a duty cycle based on a present or anticipated transient condition.

Provision is made in the housing of a host to provide a socket, or sockets, to which a peripheral piece of equipment can be connected for receiving directly from the host the low voltage DC power it requires. The socket(s) are connected electrically to the outputs of a power supply (or regulator) of a host for providing the low voltage needed to power the peripheral. The power supply may be mounted on the rear face of a computer. The principal feature of the invention resides in the use of a connector for connecting the host DC power to the peripheral DC power usage device. The connector comprises pins connected to a selected resistor in the power supply. The resistor value (i.e., resistance) is selected to produce a pre-determined control voltage which is fed back to a DC to DC converter in the host's internal power supply. The converter comprises a pulse width modulation control device. The control voltage determines the duty cycle (i.e., pulse width) of the modulation to reduce the output from a maximum voltage to an appropriate voltage suitable for the particular peripheral power usage device. Thus, by simply selecting the appropriate connector (or cable) having the proper pins correlated to a selected resistor previously installed in the power supply, the voltage level for the corresponding peripheral device is automatically selected. In an alternative embodiment, the DC power distribution apparatus of the present invention comprises a stand-alone unit having one or more universal ports for receiving a cable with a connector containing the appropriate pins for a selected DC power usage device.

Electrodynamic control of fluid leakage loss is provided. Embodiments utilize electrohydrodynamic (EHD) principles to control and / or reduce leakage flow in turbomachinery. Electrodes can be used to provide a flow actuation mechanism inside the clearance gap for generating discharge. The electrodes can be positioned to have geometric asymmetry. Embodiments provide the electrodes on a turbine blade. The blade can have a DC power that can function as a square pulsed DC wave with the duty cycle equal to the blade passing frequency and the stator can be grounded. In an embodiment, the stator can have the actuator of the electrode-insulator assembly attached to the inside. In one embodiment, the actuators can be arranged just on the stator or casing. The phase and power supply to individual electrodes can be adapted as needed. In one embodiment, the phase can be lagged for accurate control of leakage flow. The control of the power supply to the electrodes can involve a closed control loop that monitors tip gap size.

Described herein are systems and methods for applying extremely low duty-cycle stimulation sufficient to treat chronic inflammation with progressively longer delays (off periods) from an initial stimulation. In particular, described herein are supra-threshold pulses of electrical stimulation sufficient to result in a long-lasting (e.g., >48 hours) inhibition of pro-inflammatory cytokines and / or effects of chronic inflammation; the delay between initial doses (which may be single-pulse doses) may be extended for subsequent doses, potentially dramatically enhancing battery and device longevity.

Exemplary systems and methods provide a transformer-isolated current-fed quadratic full-bridge converter topology. The optimal interfacing of a current source, such as a solar panel, can be implemented by using current-fed converters. The current-fed converter can operate within the whole range of a UI curve from short-circuit to open-circuit condition and its input voltage can be readily controlled. The quadratic behaviour between input and output in regard of a duty cycle allows large conversion ratios.

A sag corrector apparatus for providing voltages temporarily (ride-through) to a load during momentary electrical disturbances in the power supply line. In one embodiment, the disclosed apparatus compensates for voltage sags by using a variable duty cycle boost converter to boost the sagged line voltage to resemble desired voltage levels during occurrence of voltage sags. The boosted voltage available to a connected load during a sag depends on a sequence of operation of various control pulses. Duty cycle of the boost converter is controlled by changing the width (duration) of the control pulses. To prevent voltage shoot-throughs from over-boosting, an energy clamp circuit is provided to dissipate excess energy. Embodiments of the sag corrector circuit can be additionally integrated with power protection functions.

A method of controlling a motor speed for a fan assembly includes receiving a duty cycle value at a microcontroller. The microcontroller receives a measured fan speed from a speed sensor. An expected fan speed is determined, where the expected fan speed corresponds to the duty cycle value. The measured fan speed is compared with the expected fan speed. A duty cycle of a motor driving signal is reduced if the measured fan speed is less than a predetermined fraction of the expected fan speed.