162results about How to "Improve light load efficiency" patented technology

Adaptive multi-mode digital control schemes that improve the light-load efficiency (and thus the overall average efficiency) in switch-mode power converters without causing performance issues such as audible noises or excessive voltage ripples. Embodiments include a switch-mode power converter that reduces current in the power converter using a second pulse-width-modulation (PWM) mode before reaching switching frequencies that generate audible noises. As the load across the output of the power converter is reduced, the power converter transitions from a first PWM mode in high load conditions to a first pulse-frequency-modulation (PFM) mode, then to a second PWM mode, and finally to a second PFM mode. During the second PFM mode, the switching frequency is dropped to audible frequency levels. Current in the power converter, however, is reduced in the second PWM mode before transitioning to the second PFM mode. Therefore, the power converter produces less or no audible noise in light load conditions where the switching frequency drops to audible frequency levels, while achieving high efficiency across varying load conditions.

The present invention discloses a voltage mode switching regulator with improved light load efficiency and mode transition characteristic, and a control circuit and a control method therefor. The switching regulator can switch between a pulse width modulation (PWM) mode and a pulse skipping mode. The control method for the switching regulator comprises: comparing a feedback signal relating to an output voltage with a reference signal, to generate an error amplification signal; generating a duty signal according to the error amplification signal and a ramp signal, to control the switching regulator; setting a threshold level of the error amplification signal and a threshold level of the pulse skipping mode according to the error amplification signal in a stable status; and when the error amplification signal is close or equal to the threshold level of the pulse skipping mode, generating a pulse skip signal to enter the pulse skipping mode.

The invention provides an asymmetric half-bridge flyback converter and a driving control method therefor. A load detection circuit detects a load signal of the asymmetric half-bridge flyback converter, compares the load signal with a set load point, forms a feedback signal by the comparison result, and outputs the feedback signal to a driving control module and a main control chip concurrently; the main control chip outputs a PWM signal to a driving circuit; the driving circuit outputs two paths of signals, namely, a main switching tube driving signal and a driving voltage signal; the main switching tube driving signal drives the switch on and switch off of a main switching tube; the driving voltage signal is input to the driving control module; and after the driving control module receives the driving voltage signal and the feedback signal, a first driving signal or a second driving signal is output to control the switch on or switch off of a clamping switching tube. The control method and the control circuit are simple and reliable, easy to realize, capable of solving the problems of high loss in light load output and no load of the asymmetric half-bridge flyback converter, and capable of improving the light load efficiency.

The present invention relates to a control circuit and a control method of a synchronous rectifier. In a preferred embodiment according to the invention, the synchronous rectifier control circuit comprises the following components: (1) a first detection circuit which is used for detecting a voltage between a first power terminal and a second power terminal before the device is switched on and generating a first control signal for regulating the switching-on time of the synchronous rectifier; (2) a second detection circuit which is used for detecting a voltage between the first power terminal and the second power terminal after the device is switched off and generating a second control signal for regulating the switching-off time of the device; and (3) a driving control circuit which receives the first control signal and the second control signal and generating a grid control signal for driving a control terminal of the synchronous rectifier.

The invention discloses a method for enhancing the non-uniform variation grid width of the light load efficiency of an integrated switch DC-DC converter, a Buck-Boost converter in the invention adopts the design of a CSMC 0.5mu m CMOS process library, whole-circuit integration is realized except for a passive filter, the external filter inductance is 2.2mu H, and the filter capacitance is 1mu F. According to the requirements of input voltage and output voltage, the converter can work in three modes: Buck (voltage reducing), Buck-Boost (voltage reducing and boosting) and Boost (voltage boosting), the range of the input voltage is 2.5V-4.2V, the range of the output voltage is 1.5V-5V, and the working frequency is 5MHz. A non-uniform grid width modulation method is adopted in the whole load current range of 10mA-650mA. When the converter works at high frequency of 5MHz, the efficiencies of medium load and heavy load keep above 90 percent all the time, and the efficiency of light load (10mA) can reach above 80 percent. As the grid width of a switching tube is only changed and a control link of the working efficiency of an extra switching tube is not adopted, negative effects caused by frequency conversion control are eliminated fundamentally.

A feedback circuit for an isolated power converter includes an opto-coupler and a reversed polarity regulator. The opto-coupler provides a current related to an output voltage of the isolated power converter. When the isolated power converter enters light load, the output voltage rises and the reversed polarity regulator reduces the current to decrease the power consumption and thus improve the light load efficiency of the isolated power converter.

The invention provides a controller for a non-complementary active clamp flyback converter. The controller comprises a frequency control unit, a pulse width control unit, a sequential control unit anda driving unit, uses a multi-mode control mode, and further comprises a wave peak detecting unit and a mode a determining unit. The wave peak detecting unit detects the peaks of an oscillating voltage at the drain end of a main switching tube, and turns on a clamp tube at the troughs in the non-complementary mode of the converter. The turning off of the clamp tube is determined by internally setturn-on time. The mode determining unit, according to feedback voltage FB, gives a mode switching signal to the sequential control unit according to a mode determining result signal. By using a DCM mode, the controller prevents the clamp tube from being turned on, reduces the peak-to-peak value of the excitation current when entering a frequency hopping mode, avoids audio noise, and optimizes no-load power consumption. Since the comparison process of the mode conversion is provided with a long time delay, the influence of mode switching on a converter control loop is reduced.

The invention discloses an asymmetric half-bridge converter and a control method thereof. A one-way clamping network is additionally arranged and is connected in parallel with a primary side, a secondary side or a third winding of a transformer, an auxiliary switch is controlled to be switched off when an excitation inductance current reaches a set value, the one-way clamping network is conducted,a clamping current passes through the one-way clamping network, the clamping current is clamped and maintained to be basically unchanged by the one-way clamping network, the one-way clamping networkis controlled to be switched off within a certain time before a main switch is conducted, the clamping current is released, voltages of two ends of the main switch are reduced to zero or be approximate to zero, and zero-voltage conduction of the main switch is achieved. By the asymmetric half-bridge converter, effective control of negative peak of the excitation inductance current can be achieved,a current effective value of a power device under light load of a converter is reduced, the light-load efficiency of the converter is substantially reduced under the condition that the advantages ofzero-voltage conduction of an existing technical scheme is maintained, the no-load loss is reduced, and control implementation is simple and efficient.

An isolated power converter, an inverting type shunt regulator, and an operating method thereof are disclosed. The isolated power converter includes a transformer, an inverting type shunt regulator, a controller, and an optocoupler. The inverting type shunt regulator is located on the secondary side of the transformer. The inverting type shunt regulator includes an error amplifier and a MOSFET. The controller is located on the primary side of the transformer. The controller includes an inverting unit cooperated with the MOSFET. The controller receives a feedback voltage. The optocoupler is coupled to the inverting type shunt regulator and the controller to provide an opto-coupling current to the controller.

A DC-to-DC converter comprises an error amplifier, a comparator, a PWM controller, a power switch unit, and a control signal monitoring circuit. The PWM controller receives a comparison signal from the comparator and generates a digital control signal that controls the power switch unit such that the DC-to-DC converter supplies a regulated voltage onto a load. The control signal monitoring circuit monitors the digital control signal and detects either a heavy load or a light load condition based on characteristics of the digital control signal. Under the light load condition, the monitoring circuit generates a first enabling signal such that the DC-to-DC controller operates in a power-save mode. Under the heavy load condition, the monitoring circuit generates a second enabling signal such that the DC-to-DC controller operates in a normal operation mode. The DC-to-DC converter consumes substantially less power in the power-save mode than in the normal operation mode.

The invention provides an interleaved parallel magnetic-integration bidirectional full-bridge LLC resonant converter and relates to the technical field of power and electronic applications. The interleaved magnetic-integration bidirectional full-bridge LLC resonant converter comprises two paths of an interleaved parallel bidirectional full-bridge LLC resonant converter. The first path of the bidirectional full-bridge LLC resonant converter comprises a first primary-side circuit, a first secondary-side circuit, a resonant transformer and a magnetic inductor thereof. The second path of the bidirectional full-bridge LLC resonant converter comprises a second primary-side circuit, a second secondary-side circuit, a resonant transformer and a magnetic inductor thereof. The primary-side circuit and the secondary-side circuit of each path of the bidirectional full-bridge LLC resonant converter are respectively in the form of a full-bridge LLC resonant circuit and are used for realizing the bidirectional energy flow. The two resonant transformers, the magnetic inductors thereof and four resonant inductors of the two paths of the interleaved parallel bidirectional full-bridge LLC resonant converter are magnetically integrated through integrated magnetic pieces. According to the technical scheme of the invention, the large-power, high-transformation-ratio, small-volume, bidirectional and high-efficiency operation of the electric energy is realized.

The invention discloses a grid-connected photovoltaic inverter device and a control method for improving conversion efficiency thereof and belongs to the field of inverter control. The device comprises N grid-connected photovoltaic inverters, wherein a voltage outer loop control circuit (3) of each grid-connected photovoltaic inverter comprises a bus voltage sampling circuit (301), first and second bus voltage regulators (302 and 303), first and second amplitude limiting circuits (304 and 305) and three voltage loops. The control method comprises that: given voltage in different grades is respectively set for the bus voltage regulators of the plurality of grid-connected inverters; along with the increase of the input power, the inverters work in turn according to the given voltage, and the light load efficiency is improved by reducing the number of the operating inverters under the condition of light load; and different set values and output amplitude limiting values are applied to a linear bus voltage regulator of a single grid-connected inverter so as to ensure that the inverters can operate at the highest efficiency preferentially under different power grades, and the overall efficiency of the system is improved.

The invention discloses a working size switching circuit for power transistors in a DC-DC converter, mainly solving the problem of difficulty in reaching high efficiency by the traditional DC-DC converter when in a low load state. The working size switching circuit comprises a pulse width modulation (PWM) comparing module, a first drive module, a first pair of power MOS (Metal Oxide Semiconductor) transistors, a hysteresis comparing module, a second drive module and a second pair of power MOS transistors, wherein the PWM comparing module controls the first pair of power MOS transistors to work through the first drive module; the hysteresis comparing module compares a load current with a switching threshold current to generate a judging signal and controls that the second pair of power MOS transistors does not work when the load current is lower than the switching threshold current through the second drive module and the second pair of power MOS transistors works when the load current is more than the switching threshold current, so that actually working power transistors of the DC-DC converter are different in quantity under same load conditions, and the working size of the power transistors are switched. According to the working size switching circuit, the efficiency of the DC-DC converter when in the light load state can be increased, and load currents corresponding to the switching of the working sizes of the power transistors are constant under various working duty ratios.

A MOSgated device has spaced vertical trenches lined with a gate oxide and filled with a P type polysilicon gate. The gate oxide extends along a vertical N⁻ channel region disposed between an N⁺ source region and an N⁻ drift region. A Schottky barrier of aluminum is disposed adjacent the accumulation region extending along the trench to collect holes which are otherwise injected into the source region during voltage blocking. A common source or drain contact is connected to the N⁺ region and to the Schottky contact. A two gate embodiment is disclosed in which separately energized gates are connected to alternatively located gate polysilicon volumes.

The invention discloses an LLC resonance power converter with double resonance frequencies. On the basis of the traditional LLC resonance power converter resonance network formed by two bridge arms and four NMOS transistors M3, M4, M5 and M6, a bridge arm formed by NMOS transistors M1 and M2 is additionally arranged, an active network is formed together with an inductor La, an isolation transformer and a Class D full bridge rectifier are serially connected sequentially, the Class D full bridge rectifier is sequentially connected with a sampling circuit, an error amplification circuit, an STM32F407 microcontroller and a high-frequency gate driving circuit via a load R, and output of the high-frequency gate driving circuit drives three bridge arms and six MOS transistors from M1 to M6 in the resonance network additionally provided with the active network to work normally. The LLC resonance power converter with double resonance frequencies has two working modes, the light-load efficiency of the LLC resonance converter is greatly improved, a switching frequency range is narrow, and symmetric work in a full load range is realized.