The invention provides a laser converter for converting a laser radiation of shorter wavelength to a laser radiation of longer wavelength using a single stage conversion. The laser converter comprises a laser diode for emitting a laser radiation in a first wavelength range, a cylindrical microlens for transferring and focusing the laser radiation to a laser chip and the laser chip for absorbing the laser radiation and emitting the laser radiation in a second wavelength range.

A counter includes a buffer unit and a ripple counter. The buffer unit generates at least one least significant signal of a count by buffering at least one clock signal until a termination time point. The ripple counter generates at least one most significant signal of the count by sequentially toggling in response to at least one of the least significant signal. The counter performs multiple data rate counting with enhance operation speed and reduced power consumption.

A counter configured to perform counting at both edges of an input clock to output an additional value or a subtraction value for a previous count value and a next count value includes a first latch circuit that latches the input clock, a second latch circuit that latches an output from the first latch circuit, a holding section that holds data of the 0th bit of a count value, and a correction section that performs count correction on data of the first and subsequent bits of the count value on the basis of an output of the second latch circuit.

Disclosed herein is a device that includes first and second buffer circuits connected to a data terminal and a first control circuit controlling the first and second buffer circuits. The first control circuit receives n pairs of first and second internal data signals complementary to each other from 2n input signal lines and outputs a pair of third and fourth internal data signals complementary to each other to first and second output signal lines, where n is a natural number more than one. The first and second buffer circuits are controlled based on the third and fourth internal data signals such that one of the first and second buffer circuits turns on and the other of the first and second buffer circuits turns off.

An ergonomic back support device utilizing one or multiple vertical components that include layers (28,36), pressure distributing layers (34,38,50), and a single notched layer (48). These layers provide primary back support located behind and conforming to the Erector spinae muscles (124). The vertical components form an open channel (24) that is parallel to the prime neurological pathway of the spinal column (100). The vertical conforming support components and open channel facilitate physiological functions that promote health. The device accomplishes support without using any transverse, hard or continuous components across or against the back. Other embodiments include the following additional vertical components: a lateral pressure-adjusting device (14), heating layers (40,46), circulation stimulating layers (42,44), and massage layers (52,54). Embodiments include portable and permanently installed versions that can be utilized in the following applications, including, but not limited to, furniture, vehicles, trains, aircraft, boats, ships, and backpacks.

A data processing apparatus is monitoring the first port of itself and the second port of itself. If the data processing apparatus receives data via the second port, it conducts a specific process to the data regardless of a data format of the data so as to convert the data into the data format that can be processed regardless of a data format of the data and sends converted data to the first port.

A system for lifting a vehicle via multiple slings comprises a vehicle not engineered with structural facility to withstand lifting forces, including a frame which unmodified will deform in response to vertically imposed lifting forces, frame reinforcing elements affixed to the frame at selected locations which are subject to lifting deformation, at least two lifting members at spaced-apart forward frame locations, at least two lifting members at spaced-apart rearward frame locations, and a plurality of elongate slings extending respectively between each lifting member and a common lifting vertex. Each lifting member has an enlarged lower base portion rigidly affixed to the frame and an upper lifting portion. The frame reinforcing elements resist deformation of the frame in response to vertically imposed lifting forces. The enlarged base portions of the lifting members apply forces over a correspondingly enlarged area of the frame and the reinforcing elements without deforming the frame.

A digital phase locked loop (DPLL), a method of operating the same, and a device including the same are provided. The DPLL includes a digitally-controlled oscillator configured to change a frequency and a phase of an output oscillation signal in response to a digital control code; a main divider configured to divide the frequency of the output oscillation signal and generate a first feedback signal based on the divided frequency; and a phase-to-digital converter configured to subdivide the phase of the output oscillation signal and to generate a quantized code by converting a phase difference between a reference signal and the first feedback signal using a phase-subdivided signal resulting from the subdivision. The digital control code is generated based on the quantized code.

Methods, systems, and apparatuses are described for compensating for an undesired fractional spur due to a PLL in a communication system. The communication system includes a time-to-digital converter (TDC) that is configured to execute in parallel to the PLL. The TDC is configured to determine a phase difference between a reference frequency and an output oscillation signal provided by the PLL. The phase difference is received by a processor to estimate particular characteristics of the undesired fractional spur, and the estimate of the characteristics is used to construct an estimate of the undesired fractional spur.

The present invention relates to a method of and a vertical pumping device (1) for internally distributing Hg in a fluorescent tube body (3). The bottom (7) of the fluorescent tube body (3) is closed. The device (1) arranges, in a first position, a first solid body (9') comprising a predetermined first amount of bound Hg. The device (1) arranges, in a second position, a second solid body (9″) comprising a predetermined second amount of bound Hg. A first release (E1) of the first amount of Hg is achieved in the fluorescent tube body (3) by gasification with heat and under pressure for purification of contaminant particles in the fluorescent tube body. A second release (E2) of the second amount of Hg is achieved in the fluorescent tube body (3) by gasification attained for the occluded mercury vapour of the fluorescent tube body (3).

An appliance is provided having one or more racks or shelves, the position of which may be adjusted vertically. Multiple different positions along the vertical direction can be made available for selection by a user of the appliance. One or more mechanisms allow for the selective adjustment and securing of the vertical position at which a shelf may be located.

The present invention pertains to a modular furniture system in which a flat-foldable or easily assembled and disassembled rigid base structure composed of rectangular-cross-sectioned pieces each with specific dimensions serves variously, once assembled, as the supporting framework for a flat-foldable chair seat-and-backrest module, which configured together with the base structure serves as either an upright dining chair with armrests or as a lower and more reclined lounge chair with armrests, or alternatively as configured for supporting the connectable or foldable components of a flat planar surface module to be used for dining or to serve as a desktop, or alternatively as configured for supporting a storage cabinet module with drawers or doors.

A solar power inverter having a sealing means includes: a main case having an opening on a front surface thereof, the opening open and closed by a main cover; an auxiliary case coupled to one side surface of the main case, and having a second opening on a front surface thereof, the second opening open and closed by an auxiliary cover; and a gasket interposed between the main case and the auxiliary case, wherein the main case and the auxiliary case are coupled to each other by coupling bolts which pass through the main case, the gasket and the auxiliary case.

A power converter is configured to include an inverter which converts a DC output into an AC voltage of a predetermined frequency, and a high voltage generator which receives an output from output terminals of the inverter and boosts the output to a desired high DC voltage. The high voltage generator includes a transformer, and the primary windings of the transformer are connected to the output terminals of the inverter in parallel by conductive wires connected to both ends of each primary winding. Further, a current sensor is provided to detect a current flowing through each of the primary windings, and a control unit determines abnormalities of a path of the inverter and the primary windings on the basis of a value of the current sensor.

An inverter generator used in combination with a motor and an ECU generating a pulse at each predetermined rotation angle of the motor is comprised of: an electric generator driven by the motor configured to generate alternating current electric power; estimating means for estimating an electrical angle of alternating voltage of the alternating current electric power from the pulse, the estimating means being electrically connected with the ECU; a converter configured to convert the alternating current electric power into direct current electric power, the converter electrically connected with the electric generator and the estimating means; and an inverter configured to convert the direct current electric power into alternating current output electric power, the inverter electrically connected with the converter.

A generator system includes a generator having a stationary portion and a rotating portion. An exciter field winding and a main armature winding are disposed on the stationary portion. An exciter armature winding and a main field winding are disposed on the rotating portion. A frequency demodulator is configured to extract a frequency modulated control signal from the exciter armature winding and to demodulate the frequency modulated control signal to generate a demodulated control signal. The generator includes a main field rotating power converter to selectively control current in the main field winding in response to the demodulated command signal. The generator system includes a generator control unit in electrical communication with the generator to monitor the output voltage at the main armature winding and to output an exciter current including the frequency modulated control signal to the exciter field winding based on the output voltage.

A method of operating a converter of a wind turbine for providing electric energy to a utility grid includes determining a grid voltage. If the grid voltage is between a nominal voltage and a first voltage threshold, i.e. higher than the nominal voltage, a normal procedure for lowering the grid voltage is performed. If the grid voltage is above the first voltage threshold, another procedure for keeping the wind turbine connected is performed, wherein the other procedure is different from the normal procedure. Further a corresponding arrangement is described.

Systems and methods for reducing current imbalance between parallel bridge circuits used in a power converter of a doubly fed induction generator (DFIG) system are provided. A control system can monitor the bridge current of each of the bridge circuits coupled in parallel and generate a feedback signal indicative of the difference in bridge current between the parallel bridge circuits. Command signals for controlling the bridge circuits can then be developed based on the feedback signal to reduce current imbalance between the bridge circuits. For instance, the pulse width modulation of switching devices (e.g. IGBTs) used in the bridge circuits can be modified to reduce current imbalance between the parallel bridge circuits.

A double fed induction generator (DFIG) converter method are presented in which rotor side current spikes are attenuated using series-connected damping resistance in response to grid fault occurrences or grid fault clearances.

A DC voltage converter includes an oscillator that converts a DC battery voltage to an oscillating voltage, a low voltage transformer that increases the oscillating voltage to a higher oscillating voltage, and a voltage rectifying-capacitor charging network or multiplier that increases the higher oscillating voltage to yet a higher DC voltage at an output terminal for DC high voltage utilization devices and the like. An electric control switch is selectively actuated by the user to apply the battery voltage to the oscillator, resulting in the generation of the stepped-up DC voltage at an output terminal. Another DC voltage converter has an electronic switching circuit that automatically turns the oscillator on and off and a load capacitor across the electrodes that is charged and discharged to provide a shocking voltage. Utilization devices for the voltage developed by the converter shown are a miniature animal training device and a cattle prod device. The miniature animal training device has a pair of outwardly projecting electrodes mounted on a side at one end of the housing that is sized and shaped to fit within and conform to the palm of a hand. The cattle prod device has a pair of electrodes fixedly mounted on the end of a housing assembly made up of telescoping tubular housing sections arranged for relative axial movement whereby the pressing of the electrodes against an object to be shocked actuates the electric control switch and causes a shock of the object. The housing assembly is releasably supported by a rigid handle or an extensible handle assembly.

The present invention relates to a gum dispenser for automatically dispensing gum by the vertical lifting of a gum case. Particularly, the present invention provides a container that has a self-sealing means, accurately dispenses a piece of gum one by one, prevents the generation of container defects, and provides ease of operation and molding. Currently, in the above operation structure, an inner case receiving gum therein is fitted in a lifting shaft of an outer case to be lifted or lowered so that a piece of gum is pushed up to an upper end of the lifting shaft, and then the gum is exposed to a dispensing hole perforated in a lid, which is coupled with the inner case, one by one for a user to enjoy. The above structure, however, has a disadvantage in that if two pieces of gum are lifted to the upper end of the lifting shaft and the lifting shaft is exposed to the perforated hole of the lid, then the lifting shaft and the dispensing hole correspond to each other 1:1 so that the two pieces of gum pop out, which makes the gum difficult to catch. In addition, if the lifting shaft is molded integrally with the outer case, the lifting shaft is likely to be twisted or bent due to the thickness thereof in the cooling procedure during the molding thereof so that it is difficult to achieve a precisely standing structure. Furthermore, if the inner case is repetitively lifted or lowered in the outer case, an outer force may be applied in the lifting motion according to a vacuum state, so that smooth operation becomes impossible and longer molding time is required in the molding. In addition, in the state that the lid is sealingly coupled with the outer case and the inner case for the sealing of the container during storage or delivery thereof, a perforated lid for implementing the dispensing hole may be pressed by the lifting shaft and the container may burst. If the perforated lid is formed to be thick in order to prevent the bursting, a pulling portion to be pulled for cutting the perforated lid is likely to be cut, and implementation of the dispensing hole may fail. As a result, the present invention is aimed at resolving the above problems.

A vertical tilling implement to be pulled behind and agricultural vehicle having a number of gangs of fluted-concave disc blades, rolling baskets, and wheels connected to a main frame. As the vertical tilling implement is pulled, the fluted-concave disc blades move the soil in a direction lateral to the side of the blades as well as up. Meanwhile, the rolling bars aid in leveling the seedbed and crushing the remaining large pieces of soil. The vertical tilling implement reduces the amount of subsoil compaction and cuts through heavy residue making it ideal for use in the fall or in the spring.

A low resistivity interface material is provided between a self-aligned vertical heater element and a contact region of a selection device. A phase change chalcogenide material is deposited directly on the vertical heater element. In an embodiment, the vertical heater element in L-shaped, having a curved vertical wall along the wordline direction and a horizontal base. In an embodiment, the low resistivity interface material is deposited into a trench with a negative profile using a PVD technique. An upper surface of the low resistivity interface material may have a tapered bird-beak extension.

A ski system includes a ski, a heel binding provided on an upper surface of the ski, a toe binding mount provided on the upper surface of the ski forward of the heel binding, a toe binding releasably mounted to the toe binding mount, and a quick-release locking mechanism for locking the toe binding to the toe binding mount. The quick-release locking mechanism is configured for release by hand.

A sensor includes a collector, an emitter and a base-region barrier formed as an inverted bipolar junction transistor having a base substrate forming a base electrode to activate the inverted bipolar junction transistor. A level surface is formed by the collector, the emitter and the base-region barrier opposite the base substrate such that when the level surface is exposed to charge, the charge is measured during operation of the bipolar junction transistor.

Provided is an A/D converter including an input terminal, a reference signal line for supplying a reference signal which changes temporally, a comparator, a correction capacitor connected to an inverting input terminal of the comparator; and an output circuit which outputs digital data corresponding to an analog signal input to the input terminal. In a first state in which a total voltage of a first analog signal and an offset voltage of the comparator is held in the correction capacitor, a second analog signal input to the input terminal is supplied to a non-inverting input terminal of the comparator, and the second analog signal or the total voltage is changed using the reference signal, thereby outputting, from the output circuit, digital data.

A media diverter system for directing a media sheet traveling along an input media path into either a first media path or a second media path. One or more roller assemblies are provided including a media-guiding roller having one or more grooves formed around the exterior surface, and an air source for selectively providing an air flow into one or more of the grooves, the air flow being directed between the media sheet and the exterior surface of the media-guiding roller thereby producing a Bernoulli force to draw the media sheet toward the media-guiding roller. A controller selectively activates the air source in at least one of the roller assemblies while the corresponding media-guiding roller rotates around its roller axis to draw the media sheet toward the exterior surface of the media-guiding roller, thereby directing the media sheet into either the first media path or a second media path.

An apparatus (10) for transporting items includes a base (12), a handle element (16) extending from the base (12), a pair of rollers or wheels (20) mounted to the base (12) and a platform (14) mounted to the base (12) and adapted for movement between a stored condition and an operative position. The platform (14) includes first and second leg elements (24) and a platform support (26) connected to the first and second leg elements (24) and extending therebetween. The platform (14) is dimensioned and adapted to carry an object when in the operative position. The platform support (26) may comprise a flexible material such as a fabric material.

A power converter with positive and negative supply rail outputs for feeding a single ended class D amplifier, the converter comprising a transformer arrangement, a supply pump reduction arrangement connected between the secondary windings and the positive and negative supply rail outputs, and a boost drive mode switching arrangement. A controller is adapted to control the power converter in a negate drive mode and a boost drive mode, wherein the output voltage in the boost mode is increased by means of the transformer and the boost drive mode switching arrangement. The output voltages on the positive and negative rails can be generated at two different output voltage levels without changing the duty cycle or dead time of the control signals.

An apparatus is described that includes an audio power amplifier having an input and an output. An alternating-current to direct-current power converter is coupled to the audio power amplifier in a single package to supply power to the audio power amplifier.

A voltage converter can be switched among two or more modes to produce an output voltage tracking a reference voltage that can be of an intermediate level between discrete levels corresponding to the modes. One or more voltages generated from a power supply voltage, such as a battery voltage, can be compared with the reference voltage to determine whether to adjust the mode. The reference voltage can be independent of the power supply voltage.

The present invention is a serial to parallel data conversion method and device where new serial data are stored within a first n-bit register prior to presentation at an n-bit parallel output. Subsequently, additional data are stored within a second n-bit register while the data stored within the first register are presented at the parallel output. Data storage and data presentation are thereafter alternated, thereby eliminating the problem of setup time seen in prior art.

An analog-to-digital converter can use a variable sampling rate. By using a variable sampling rate analog-to-digital converter and an anti-aliasing filter lower sampling rates, and accordingly, generally lower power consumption may be achieved. For example, a lower sampling rate can be used when it is determined that no undesirable signals are present and a higher sampling period can be used when an undesirable signal is present. Determining the presence of an undesired signal can be based on signal-to-noise ratio, over-sampling, bit error rate, using a detector, etc. An undesirable signal can be any signal that is close in frequency to a signal of interest or a signal farther away in frequency that has a relatively high amplitude. Sampling rate can be varied in a binary fashion, stepwise, continuously, etc.

A thermoplastic energy absorber having a horizontal axis and a vertical axis, and comprise: an array of energy absorbing lobes protruding from a base, the lobes arranged in two or more rows. The energy absorbing lobes can have a vertical length (L) and a horizontal width (D), and wherein a ratio of L:D is greater than 1. The energy absorbing lobes in each row can be disposed in a staggered manner with respect to energy absorbing lobes in an adjacent row. The energy absorber can be configured to be installed on a vehicle for absorption of impact energy. An energy absorbing system can comprise the thermoplastic energy absorber disposed between a bumper beam and a fascia. The fascia can optionally be configured to envelope the thermoplastic energy absorber and the bumper beam. This system passes EuroNCAP lower-leg impact requirements, version 5.1, June 2011, for lower leg impact requirement.

A method of casting a core includes the steps of preparing a first half of a corebox, preparing a second half of a corebox such that the parting line of a core formed from the first and second coreboxes runs along the vertical axis of the core.

The present disclosure relates to a material reducing machine convertible between a grinding configuration and a chipping configuration. The material reducing machine includes a rotary component that is rotatable about an axis of rotation, the rotary component defining a grinding configuration boundary that extends at least partially around the axis of rotation. The material reducing machine also includes a plurality of hammers secured to the rotary component, the hammers including end portions that project outwardly beyond the grinding configuration boundary of the rotary component. Furthermore, the material reducing machine includes a boundary enlarging structure that mounts over the rotary component, the boundary enlarging structure defining a chipping configuration boundary that extends at least partially around the axis of rotation when the boundary enlarging structure is mounted over the rotary component, the chipping configuration boundary being positioned outside the grinding configuration boundary. The boundary enlarging structure is not mounted over the rotary component when the material reducing machine is in the grinding configuration and the boundary enlarging structure is mounted over the rotary component when the material reducing machine is in the chipping configuration.

A DC-DC converter includes a first amplifier that amplifies a first difference between a first reference voltage and a feedback voltage corresponding to an output voltage, a second amplifier that amplifies a second difference between the first reference voltage and an integrated value of the feedback voltage, and a controller that controls a switching circuit to change the output voltage when the first difference reaches the second different.

A method of operating a switching power converter may include determining an average value of a measured parameter for substantially each switching cycle, and adjusting a control parameter during substantially each switching cycle in response to a corresponding one of the average values. In one embodiment, the control parameter comprises a switch duty cycle, and the measured parameter comprises an output current. Determining the average value of the measured parameter may include obtaining a first sample of the measured parameter during a switching cycle, and calculating the average value of the measured parameter during the switching cycle in response to the first sample.

Efficiency of a switch mode power supply (SMPS) is optimized by operating the SMPS in an asynchronous mode when current being supplied therefrom is less than a certain current value and operating the SMPS in a synchronous mode when the current being supplied therefrom is equal to or greater than the certain current value. When the SMPS is operating in the synchronous mode high-side and low-side power transistors alternately turn on and off. When the SMPS is operating in the asynchronous mode only the high-side power transistor turns on and off and the low-side power transistor remains off. When charging a battery with the SMPS discharge of the battery is eliminated when operating in the asynchronous mode at a low current output.

A power conversion system has a power converter configured to receive an input voltage signal, convert the input voltage to an output voltage signal, and provide the output voltage signal to a load and a closed loop compensator configured to receive the output voltage signal and a reference voltage signal, the closed loop compensator configured to transmit an error signal indicative of a difference between the output voltage signal and the reference voltage signal. The power conversion system further has a pulse with modulator configured to receive the error signal and modulate a control signal with the error signal to control the output voltage signal, the pulse width modulator configured to transmit the control signal to the power converter and logic configured to receive the error signal and control the closed loop compensator based upon the error signal. A controller observes the error signal characterstics such as peak-to-peak values, frequency and phase and adjust the closed loop controller variables and other power converter system variables in order to improve the dynamic performance and improve stability.

A DC/DC converter arrangement includes an input terminal to receive a supply voltage, an output terminal to provide an output voltage and a switching arrangement, including a coil and at least two switches to provide a Buck-Boost conversion. The arrangement further includes a current detection circuit which is coupled to the switching arrangement for sensing a coil current and a comparator, including a first input which is coupled to the output terminal and a second input which is coupled to an output of the current detection circuit. An output of the comparator is coupled to the switching arrangement. Furthermore, the arrangement includes a ramp generator which is coupled to the first or the second input of the comparator.

The present disclosure is directed to a voltage-to-current sensing circuit having a bias terminal configured to receive a reference voltage, an offset terminal configured to receive an offset current, and an operational amplifier configured to output a low voltage signal. The device includes a first amplifier having first and second high voltage inputs configured to receive a first voltage difference across a sense component on a high voltage line and to generate a first current, a second amplifier having first and second low voltage inputs configured to receive a second voltage difference between the bias terminal and the offset terminal and to generate a second current, a summing circuit configured to provide an intermediate voltage corresponding to a sum of the first and the second currents, and a low-voltage transistor coupled to an output of the amplifier and controlled by the intermediate voltage to generate the output current.

A controller used in a buck-boost converter includes a clock generator, an error amplifying circuit, a comparing circuit, a proportional sampling circuit, a logic circuit, a pulse width increasing circuit, first and second driving circuits. Based on a clock signal generated by the clock generator, the proportional sampling circuit samples the difference between a current sensing signal and a compensation signal generated by the error amplifying circuit, and generates a proportional sampling signal. The pulse width increasing circuit generates a sum control signal based on the proportional sampling signal and a logic control signal generated by the logic circuit, wherein a modulation value adjusted by the proportional sampling signal is added to the pulse width of the logic control signal to generate the pulse width of the sum control signal. The first and second driving circuits generate driving signals based on the sum control signal and the logic control signal.

A method for controlling voltage crossing a power switch of a switched-mode power converter includes the steps of: controlling a switch frequency of the power switch of the switched-mode power converter to a first frequency as activating the switched-mode power converter; and then changing the switch frequency of the power switch to a second frequency after the switched-mode power converter is activated for a predetermined time; wherein the first frequency is lower than the second frequency.

In one implementation, a modular power converter having a reduced switching loss includes a package, a field-effect transistor (FET) including a gate terminal, a drain terminal, and a source terminal, and fabricated on a semiconductor die situated inside the package, and a driver circuit inside the package. The driver circuit is configured to drive the gate terminal of the FET. The driver circuit is further configured to sample a drain-to-source voltage (VDS) of the FET directly from the drain terminal and the source terminal, thereby enabling the reduced switching loss.

A “windowless” H-bridge buck-boost switching converter includes a regulation circuit with an error amplifier which produces a ‘comp’ signal, a comparison circuit which compares ‘comp’ with a ‘ramp’ signal, and logic circuitry which receives the comparison circuit output and a mode control signal indicating whether the converter is to operate in buck mode or boost mode and operates the primary or secondary switching elements to produce the desired output voltage in buck or boost mode, respectively. A ‘ramp’ signal generation circuit operates to shift the ‘ramp’ signal up by a voltage Vslp(p−p)+Vhys when transitioning from buck to boost mode, and to shift ‘ramp’ back down by Vslp(p−p)+Vhys when transitioning from boost to buck mode, thereby enabling the converter to operate in buck mode or boost mode only, with no need for an intermediate buck-boost region.

This disclosure relates to radio frequency (RF) power converters and methods of operating the same. In one embodiment, an RF power converter includes an RF switching converter, a low-drop out (LDO) regulation circuit, and an RF filter. The RF filter is coupled to receive a pulsed output voltage from the RF switching converter and a supply voltage from the LDO regulation circuit. The RF filter is operable to alternate between a first RF filter topology and a second RF filter topology. In the first RF filter topology, the RF filter is configured to convert the pulsed output voltage from a switching circuit into the supply voltage. The RF filter in the second RF filter topology is configured to filter the supply voltage from the LDO regulation circuit to reduce a ripple variation in a supply voltage level of the supply voltage. As such, the RF filter provides greater versatility.

This disclosure relates to radio frequency (RF) power converters and methods of operating the same. In one embodiment, an RF power converter includes an RF switching converter, a low-drop out (LDO) regulation circuit, and an RF filter. The RF filter is coupled to receive a pulsed output voltage from the RF switching converter and a supply voltage from the LDO regulation circuit. The RF filter is operable to alternate between a first RF filter topology and a second RF filter topology. In the first RF filter topology, the RF filter is configured to convert the pulsed output voltage from a switching circuit into the supply voltage. The RF filter in the second RF filter topology is configured to filter the supply voltage from the LDO regulation circuit to reduce a ripple variation in a supply voltage level of the supply voltage. As such, the RF filter provides greater versatility.

A switching power converter includes a voltage source that provides an input voltage Vin to an unregulated DC/DC converter stage and at least one buck-boost converter stage to produce a desired output voltage Vout. The unregulated DC/DC converter stage is adapted to provide an isolated voltage to the at least one regulated buck-boost converter stage, wherein the unregulated DC/DC converter stage comprises a transformer having a primary winding and at least one secondary winding and at least one switching element coupled to the primary winding. The at least one buck-boost converter stage is arranged to operate in a buck mode, boost mode or buck-boost mode in response to a mode selection signal from a mode selection module. By influencing the pulse width modulation output power controller the at least one buck-boost converter stage is arranged to produce one or multiple output voltages.

A constant on-time switching converter includes a switching circuit, an on-time control circuit, a comparing circuit and a logic circuit. The switching circuit has a first switch and is configured to provide an output voltage to a load. The on-time control circuit generates an on-time control signal to control the on-time of the first switch. The comparing circuit compares the output voltage of the switching circuit with a reference signal and generates a comparison signal. The logic circuit generates a control signal to control the first switch based on the on-time control signal and the comparison signal. When the switching frequency of the switching circuit approaches an audible range, the switching converter enters into a sleep mode, the on-time control signal is reduced to increase the switching frequency of the switching circuit.