132results about How to "Improve circuit efficiency" patented technology

The present invention relates to regulated power supplies or ballasts integrated with an LED light source. The invention provides a power factor correction scheme producing a greater circuit power factor and improved frequency spectrum characteristics, in which a voltage corresponding to the instantaneous inductor current is sampled and compared to a scaled sample of the rectified input AC line voltage. The line voltage sample modulates the inductor peak charge current in the envelope of the rectified AC voltage waveform. This drives the LED output voltage at a frequency of twice the input line voltage frequency, such that no flicker is perceived in the light output because the persistence in LED phosphor assists in averaging the flux output.

A voltage boost power converter circuit, having an input inductor, active switch, and a transformer having primary, secondary and auxiliary windings. A clamping capacitor and a first passive switch are in series across the primary winding. The auxiliary winding and a second passive switch are in series, connected to the node between the clamping capacitor and first passive switch. The active switch is connected between ground the primary winding. A bulk capacitor forms a series loop including the active switch and primary winding. The method efficiently resets a the transformer, by transferring power to a load through the primary winding, and discharging a clamping capacitor through a separate inductively linked winding of the transformer during an ON state; and clamping the active switch voltage with the clamping capacitor, charging the clamping capacitor with a leakage inductance of the transformer, and charging the bulk capacitor during an OFF state.

In an insulation type AC-dc converter in which input current from a commercial power supply is converted to obtain insulated direct current, the overall efficiency is raised and the structure is simplified. A multi-resonance type half-bridge DC-DC converter having an insulation transformer T is used as a first converter, and a boosting chopper circuit for power factor improvement is used as a second converter. Hence through multi-resonance operation, increases in losses can be suppressed even when the switching frequency is raised, and because a half-bridge circuit is used, switching elements and similar with lower voltage ratings can be employed, whereby overall efficiency can be increased. Moreover, a voltage substantially similar to the full-wave rectified waveform of the power supply voltage is obtained from the output capacitor at the boosting chopper circuit input, whereby there is no need for a feed-forward circuit across the insulation transformer, and moreover the electrolytic capacitor which had to be provided on the converter input side is unnecessary. This is advantageous for achieving miniaturization and a thin design.

A system and method for power conversion synchronizes multiple phases at a desired phase angle difference. The power conversion involves variable frequency switching, fixed on-time and provides power factor correction. A relative measure of a phase angle difference between two phases permits each phase to be controlled to obtain the desired phase angle difference. The power conversion involves transition mode switching to help reduce switching losses. A phase angle difference detector may be provided for each phase. The various phases may have different inherent frequencies that vary with switching frequency, and are synchronized to an average frequency. Current measures can be taken with a single component, such as a resistor. A maximum frequency control limits period width to avoid high frequency switching. An added switch on time improves input voltage crossover distortion. One or more phases can be deactivated in light load conditions.

An LCD backlight driving system includes a light source, which is composed of at least one of each of red, green and blue LED arrays each with a plurality of corresponding color LEDs connected in series, and a substrate on which the red, green and blue LED arrays are disposed to emit white light. The system also includes an SMPS having an AC-DC converter for converting an externally inputted AC voltage to a DC voltage and red, green and blue LED DC-DC converters each converting the DC voltage to a predetermined magnitude of DC voltage suitable for driving the corresponding color LED arrays, respectively. The system further includes a control board having at least one of each of red, green and blue LED constant current controllers for regulating current running through the red, green and blue LED arrays, to maintain predetermined outputs of the red, green and blue LEDs.

This invention discloses active clamp zero-voltage soft switch high gain boost staggered parallel converters including two power switch tubes, two clamp switch tubes, two clamp capacitors, two continuing flow diodes and two coupled inductors, in which, each of the two coupled inductors includes three windings, which utilizes the second and third windings of the two coupled inductors to realize high gain output of the converter, utilizes a serial circuit composed of the two clamp switch tubes and two clamp capacitors to absorb and transfer harmlessly the leak energy of the two coupled inductors and realizes turn on of zero voltage of two power switch tubes and zero voltage turn-off of them utilizing the parallel capacitors of the two switch tubes to further realize zero-voltage turn on and off of the two clamp switch tubes.

The invention relates to a three-state three-level PFC circuit, which comprises an inductor, a combined three-state switch, a first capacitor and a second capacitor. The inductor is connected between a first end of an AC power supply and a first end of the combined three-state switch; a second end of the combined three-state switch is connected at a first end of the first capacitor; a third end of the combined three-state switch is connected at a second end of the second capacitor; a fourth end of the combined three-state switch is grounded; and the first end of the first capacitor, a second end of the first capacitor, and the second end of the second capacitor output three-level voltage. The invention also provides a multi-state three-level PFC circuit correspondingly. Compared with the common circuit without a three-state switch or a multi-state switch, the PFC circuit provided by the invention can obviously reduce the dimensions of the inductor and the capacitors, improve the powerfactor of the circuit simultaneously and reduce the total harmonic content on the premise of maintaining the switch frequency and ripples on a passive device invariable, and can reduce the switch frequency and obviously improve the circuit efficiency on the premise of maintaining the input current ripple frequency and magnitude invariable.

A bridgeless PFC power converter comprises a first inductor and a second inductor coupled from a first input-terminal and a second input-terminal to a first transistor and a second transistor. A first diode and a second diode are coupled from the first transistor and the second transistor to an output capacitor. A first capacitor and a second capacitor are coupled from the input-terminals to the ground terminal through a third transistor and a fourth transistor. A control circuit generates a first-switching signal and a second-switching signal to control the first transistor and the second transistor. The second-switching signal will turn on the second transistor when the first-switching signal switches the first transistor. The first-switching signal will turn on the first transistor when the second-switching signal switches the second transistor. The control circuit turns off the third transistor and the fourth transistor during the light-load of the PFC power converter.

The invention discloses a resonance direct current / direct current converter and control method, it adjusts output voltage by changing conducting frequency of input switch of the resonance circuit, adjusts the shift angle of said switch according to feedback signal of load circuit to extend the output range of voltage of the resonance circuit. The invention also provides structure of the resonance direct current / direct current converter with said method. The advantages of the invention are following: adopting frequency modulation and frequency modulation+ shift phase control mode to control the resonance direct current / direct current converter, using frequency modulation when operating frequency of power source is low, using frequency modulation+ shift phase when operating frequency of power source is too high, the problem of resonance converter is resolved, that is problem of high operating frequency and big spoilage, and the output voltage adjustment capability of resonance circuit increased greatly, the output voltage range is extended efficiently.

A bridgeless PFC power converter comprises a first inductor and a second inductor coupled from a first input-terminal and a second input-terminal to a first transistor and a second transistor. A first diode and a second diode are coupled from the first transistor and the second transistor to an output capacitor. A first capacitor and a second capacitor are coupled from the input-terminals to the ground terminal through a third transistor and a fourth transistor. A control circuit generates a first-switching signal and a second-switching signal to control the first transistor and the second transistor. The second-switching signal will turn on the second transistor when the first-switching signal switches the first transistor. The first-switching signal will turn on the first transistor when the second-switching signal switches the second transistor. The control circuit turns off the third transistor and the fourth transistor during the light-load of the PFC power converter.

The disclosed insulation-type multiplex output dc-dc converter comprises a first and second inverter bridge arms with two full-control primary assembles with an anti-parallel diodes, a first and second output circuits between the center of first / second inverter bridge arm and power load, respectively; a third output circuit between center of two bridge arms; every output circuit contains a blocking capacitor, a transformer, two rectifier diodes, and a filter capacitor and a inductance; adjusting the duty ratio of the first / second bridge arm to change the output voltage of first / second output voltages, and the phase-shift between first and second bridge arm to adjust the output voltage of the third output voltage. This invention has little switch loss with high efficiency, and has wide application.

An active clamping high-gain alternate parallel voltage boosting convertor disclosed by the invention comprises two power switching diodes, two output diodes, two clamping diodes, two auxiliary power switching diodes, two clamping capacitors, two switching capacitors, an output capacitor and two coupling inductors. Two coupling inductors respectively comprise two windings. The present invention uses the second winding of two coupling inductors and two switching capacitors to realize the high-gain output of the convertor. With the leakage inductance of two coupling inductors, two clamping capacitors, the shunt capacitor existing in two power switching diodes themselves and the gate arrangement of two power switching diodes and two auxiliary power switching diodes, the zero voltage switching-on and zero voltage switching-off of two power switching diodes and two clamping diodes are realized. The soft switching-off of two output diodes and two clamping diodes are realized with the leakage inductance of two coupling inductors, and the circuit does not include energy losing element and the output gain of the convertor and the circuit efficiency can be increased.

The invention discloses a full-bridge zero-voltage boost switching resonant converter based on LLC used for UPS. The converter is characterized in that resonant converting circuit in DC / DC convertingmodule is full-bridge LLC resonant converting circuit and the converting circuit comprises switch bridge which is composed of four main switching tubes through full-bridge connection, main transformerof which primary winding is in parallel with excited inductor, series resonance inductors connected with the main transformer, series resonance capacitors, and LLC resonance network composed of excited inductor, series resonance inductors and series resonance capacitors, wherein the network is connected with the two output ends of the switch full-bridge, and output sides of the main transformer is synchronous full wave rectifying circuit composed of two groups of rectifying diodes and are separately connected with two output capacitors sharing the same ground wire. The full-bridge zero-voltage boost switching resonant converter of the invention overcomes the defect that switch tube zero-voltage conduction in full scope is hard to realize, the work is easy to reach optimal state, the testvalue of the practical boosting circuit efficiency is about 95%, the volume of electromagnetic elements is reduced, the circuit is simplified and the cost is reduced.

A single-stage isolated high power factor AC / DC converter with a leakage inductor energy recovery function includes a buck-boost circuit, for step-down or step-down a power supply; a transformer, electrically connected to the buck-boost circuit, for transforming the stepped-down or stepped-up power supply; a switch, electrically connected to the buck-boost circuit; an input capacitor, electrically connected to the buck-boost circuit; and an output circuit, for outputting the power supply transformed by the transformer. When the switch is cut off, the buck-boost circuit provides an energy recovery path to return energy stored in a leakage inductor of the transformer to the input capacitor. The energy stored in the leakage inductor of the transformer in a flyback converter or a forward converter is returned to the input capacitor through the energy recovery path. The problem caused by the leakage inductor of the transformer is solved without using any additional element.

A radio communication terminal has a plurality of matching circuits that optimize the efficiency of a power amplifier for a range of different battery voltages. A first matching circuit optimizes the efficiency of the power amplifier for a battery voltage higher than a predetermined threshold value. A second matching circuit optimizes the efficiency of the power amplifier at a voltage lower than the threshold value. A control section compares a detection result of a battery voltage from a voltage monitor section with the threshold value, and performs switching between the plurality of matching circuits.

A liquid crystal display (LCD) television (TV) power supply circuit is split into a backlight module power supply sub-circuit and a TV circuit power supply sub-circuit, wherein the backlight module power supply sub-circuit supplies an operation voltage to a backlight module of the LCD TV and the TV circuit power supply sub-circuit supplies plural operation voltages for a TV circuit of the LCD TV. The backlight module power supply sub-circuit includes a power factor correction circuit and an inverter, and the TV circuit power supply sub-circuit includes a DC / DC converter. The backlight module power supply sub-circuit and the TV circuit power supply sub-circuit may share a common rectifier circuit or they can be provided with direct current powers by respective rectifiers.

A method is provided for simultaneously loading and executing program code in a circuit system. The circuit system includes a plurality of memory devices, a microprocessor, and a loading circuit. The method includes dividing the program code into a plurality of code divisions and utilizing the microprocessor to execute at least a code division when the loading circuit loads any other code division into a memory device of the plurality of memory devices.

The present invention provides an impact current suppression circuit, a vehicle bi-directional charger having the impact current suppression circuit and a control method of an impact current suppression module. The vehicle bi-directional charger comprises a PFC-inversion module and an impact current suppression module, the impact current suppression module comprises a controlled switch and an impact current suppressor connected in parallel with the controlled switch. A mode of complete reuse of a charging and inversion circuit is employed to solve the problem that a high-power vehicle chargerin a severe alternating current power supply environment cannot supply specific impact circuit protection when performing bidirectional charging, improve the charging and inversion power density and circuit efficiency, achieve an isolation function comprising reduction of the EMI electromagnetic interference and reduction of the switching interference signals, achieve a more convenient boost-buckfunction, prolong the service life and the functions of the device, reduce the cost and reduce the device size.

An electronic circuit has an amplifier with an amplifying transistor and a cascode transistor. A capacitive voltage divider applies a fraction of an RF signal swing from the drain of the cascode transistor to the gate of the cascode transistor, the fraction being determined by a ratio between capacitance values. In addition a bias voltage supply circuit is provided. The bias voltage supply circuit is configured to define a relation between an average gate voltage of the cascode transistor and an average drain supply voltage at the drain of the cascode transistor. This relation increases the average gate voltage with increasing average drain voltage, and the relation provides a non zero average gate voltage when extrapolated to zero average drain supply voltage.

A charge pump circuit has an input stage, an output stage and multiple boosting stages coupled between the input stage and the output stage. The boosting stages are driven by four phase clock signals. Each boosting stage has two branch charge pumps, wherein each branch charge pump at least has a main pass transistor, a pre-charge transistor, two substrate transistors and capacitors. The substrate transistors and the main pass transistor are operated in association with the four phase clock signals to keep a potential of the body of the main pass transistors at a low level thus mitigating the body effect.

The present application provides a mixed control method for a resonant converter, a resonant converter system and a mixed controller. When the resonant converter operates in a case where a voltage gain is less than a predetermined value, the method includes: setting a mixed control start frequency, a mixed control stop frequency and a slope of a phase-shifting angle; detecting an operating frequency of the converter; calculating a time delay of phase shifting according to the slope, the mixed control start frequency, the mixed control stop frequency and a resonant frequency of the resonant converter; and according to the time delay, the mixed control start and stop frequencies, generating a control signal to adjust the operating frequency and the phase-shifting angle of the resonant converter. The present application can realize a relatively low voltage gain and a small circuit loss, thereby the circuit efficiency may be improved.

The invention discloses a neutral point clamped inverter topology for a three-phase three-level diode of a zero voltage switch and a modulation method for a neutral point clamped inverter. The topology comprises a three-phase bridge arm consisting of 12 main switches connected in antiparallel with diodes and 6 diodes, an output inductor connected between the output neutral point of the bridge arm and a load, and positive and negative bus capacitors connected between the positive end and the negative end of a direct current bus, and is characterized in that the main switches of the bridge arm is connected in parallel with a capacitor; resonant inductors are respectively connected between the positive input end of the bridge arm and the positive electrode of the positive bus capacitor as well as between the negative input end of the bridge arm and the negative electrode of the negative bus capacitor; the two ends of the resonant inductors are bridged with a circuit formed by connecting auxiliary switches with antiparallel diodes with a clamped capacitor in series; the two ends of the auxiliary switches are connected in parallel with a capacitor; short-circuit switches are respectively connected between the positive input end of the bridge arm and the negative electrode of the positive bus capacitor as well as between the negative input end of the bridge arm and the positive electrode of the negative bus capacitor. The modulation method is generating auxiliary switch and short circuit switch signals according to a main switch driving signal timing sequence of the three-phase bridge arm, so that zero voltage on and off of all the switch devices can be realized.

In an insulation type AC-dc converter in which input current from a commercial power supply is converted to obtain insulated direct current, the overall efficiency is raised and the structure is simplified. A multi-resonance type half-bridge DC-DC converter having an insulation transformer T is used as a first converter, and a boosting chopper circuit for power factor improvement is used as a second converter. Hence through multi-resonance operation, increases in losses can be suppressed even when the switching frequency is raised, and because a half-bridge circuit is used, switching elements and similar with lower voltage ratings can be employed, whereby overall efficiency can be increased. Moreover, a voltage substantially similar to the full-wave rectified waveform of the power supply voltage is obtained from the output capacitor at the boosting chopper circuit input, whereby there is no need for a feed-forward circuit across the insulation transformer, and moreover the electrolytic capacitor which had to be provided on the converter input side is unnecessary. This is advantageous for achieving miniaturization and a thin design.

The mobile communication network system of the present invention is made up from a mobile communication network (MNW), a plurality of external networks (EX1-EX3), a plurality of mobile terminals (x, y, z), a plurality of gateways (EGW1-EGW3) for connecting the external networks (EX1-EX3) and mobile communication network (MNW), and a plurality of radio access points (APa1-APc2) for connecting the mobile terminals (x, y, z) to the mobile communication network (MNW). When packets are transmitted and received between mobile terminals (x, y, z) within the mobile communication network (MNW), the packets are communicated, not by way of external networks (EX1-EX3), but by way of virtual networks that correspond to each external network (EX1-EX3) that have been prepared on the mobile communication network.

The invention discloses a single-phase soft-switching and high-gain boost converter for distributed photovoltaic power generation. The converter comprises a single-phase Booster circuit unit working in an input current continuous mode, a transformer voltage doubling circuit unit and an output circuit unit which are connected in turn, wherein the single-phase Booster circuit unit working in the input current continuous mode consists of an input filtering inductor, two power switching tubes, a parallel capacitor and a clamping capacitor; the transformer voltage doubling circuit unit consists of a transformer provided with two windings, a blocking capacitor, a voltage doubling capacitor and a freewheel diode; the output circuit unit consists of an output diode and an output capacitor; and an output circuit is connected with a load. The converter has the advantages of realizing zero voltage switch-on and switch-off of a first power switching tube and a second power switching tube, and reducing input current ripple along with simple circuit structure, convenient control and suitability for high efficiency conversion occasions of solar energy distributed power generation.

A circuit protection device with self fault detection function comprises a ground fault protection unit and a self fault detection unit, the ground fault protection unit can achieve the ground fault detection and protection function for AC power source power circuit and electrical appliance. The self fault detection unit is provided with two delay circuits which can achieve the fault detection at an early stage of power-on and periodically fault detection function. The ground fault protection circuit and the self fault detection unit can operate in time sharing, and achieve self fault detection without interruption of power supply. The self fault detection unit and the ground fault protection unit are separated from high impedance. Any fault occurred on any element in the self fault detection unit may not impair the protection ability of the ground fault protection unit.

Disclosed is a high-efficiency LED driver chip and a driver circuit of the chip, and the driver chip includes a detection unit, a comparison unit and a correction unit. The LED detection unit detects the operating current of the LED driver circuit by an external sensing resistor and an internal current mirror to output a setup signal, and the comparison unit detects the driving current of at least one LED by an external comparing resistor to output an initialization signal, so that the correction unit can output a correction signal according to the setup signal and the initialization signal to reduce the power loss of the circuit while maintaining the driving current constant, so as to improve the illumination quality and the service life of the LED.