Abstract: A device for preparing bio-oil, a system for preparing bio-oil and a method for preparing bio-oil using the same are provided. Biomass is supplied to an inclined portion of a reactor, and high-temperature hot sand is supplied to an upper side of the biomass supplied to the inclined portion. Then, a heater heats the inclined portion. Thus, the fast pyrolysis performance of the biomass can be enhanced, thereby increasing the yield of bio-oil. Also, combustion gas produced from the heater is supplied to the interior of the reactor, so that the interior of the reactor can be simply formed under a nonoxidizing atmosphere. Accordingly, the device for preparing bio-oil can be manufactured into a very simple structure.

Abstract: In a power converter, a primary coil of a transformer receives an input voltage, and a first terminal of a switch is coupled to the primary coil. An output unit includes a secondary coil of the transformer, and outputs an output voltage to which the input voltage is converted by the transformer. A switching controller receives a feedback voltage corresponding to the output voltage and a sensing voltage corresponding to a current flowing between the first terminal and a second terminal of the switch. The switching controller determines whether to perform an operation of a burst mode based on the feedback voltage. The switching controller generates a control signal by comparing the sensing voltage with a comparison voltage during a first period of the burst mode, generates the control signal by comparing the sensing voltage with a voltage corresponding to the feedback voltage during a second period of the burst mode, and transmits the control signal to a control terminal of the switch.

Abstract: A converter is disclosed for using at least one switch to convert an input signal to a square wave signal, and using the square wave signal to generate an output voltage. The converter converts the square wave signal by a switching operation of a switch and generates the output voltage, and includes a switch controller for controlling the switching operation. The switch controller generates a first signal VCT having a first period that varies according to an output voltage, controls the switching operation of the switch by using the first signal, detects the output voltage, a first current Ids2 flowing through the switch, and a level of the first signal, and controls a burst mode according to the detection results.

Abstract: An auto gain controller is provided. The auto gain controller includes a variable gain amplification unit configured to receive differential input signals, adjust an amplification gain based on an auto gain control voltage and output differential output signals. The auto gain controller also includes a peak detector configured to detect at least one peak value among the amplified differential output signals, a comparator configured to compare the at least one detected peak value with a reference voltage and generate a comparison signal, and a voltage adjusting circuit configured to adjust the auto gain control voltage and the reference voltage based on the comparison signal.

Abstract: This invention relates to a synchronous rectifier for LLC resonant converter. This method allows simple drive method for the synchronous rectifier MOSFETS by using the transformer secondary winding voltage and one-shot vibrator. The synchronous rectifier MOSFETs are turned on by being triggered to the transformer secondary side winding voltage and turned off after predetermined time set by one shot vibrator. The predetermined time is set by the resonant period of the resonant network.

Abstract: A resonant converter includes a square wave generator including a first switch and a second switch, and generating a first square wave corresponding to an input voltage by alternately turning on/off the first and second switches; a resonator including a first coil of a primary coil of a transformer, and generating a resonance waveform corresponding to the first square wave; and an output unit including a second coil of a secondary coil of the transformer, and outputting a voltage corresponding to a current generated in the second coil corresponding to the resonance waveform.

Abstract: A converter and a driving method thereof are provided. The converter includes first and second switches, and generates a square wave signal according to operations of the first and second switches. The converter includes a first capacitor and a primary coil, and resonates a driving voltage by using a driving voltage with the first capacitor and the primary coil so as to generate a driving current. The converter includes a secondary coil that forms the primary coil and the transformer, and generates output power by rectifying a current and a voltage generated in the secondary coil. In addition, the converter detects the phase of the driving current, and increases switching frequencies of the first and second switches if a phase difference of the phase of the driving current and that of the driving voltage is smaller than a predetermined value.

Abstract: In one embodiment, an SMPS includes a rectifier for generating an input DC voltage from an input AC voltage. A switching transistor is coupled to a primary coil of a transformer for generating power which is transferred to a second side of the transformer according to an operation of the switching transistor. A switching controller receives a feedback voltage corresponding to an output voltage, a sensing signal corresponding to a current flowing through the switching transistor, and a first signal corresponding to a voltage difference between a first electrode and a second electrode of the switching transistor. The switching controller controls an on/off operation of the switching transistor. The switching controller sets a threshold period whenever the first signal has a value greater than a reference value, thereby setting a plurality of threshold periods during operation of the switching mode power supply.

Abstract: The present invention relates to a switch mode power supply and a driving method for reducing switching loss and audible noise in the burst mode. The switch mode power supply includes a main switch, a power supply, an output unit, and a switch controller. The power supply includes a transformer having a primary coil connected to the main switch, and supplies power to a secondary coil of the transformer according to the operation of the main switch. The output unit is connected to the secondary coil of the transformer and outputs power supplied to the secondary coil of the transformer.

Abstract: In one embodiment, a power converter generates an output voltage by modulating an input voltage according to operations of a first switch and a second switch connected in a half-bridge arrangement. The power converter includes a switch driver circuit for controlling the turning on and off of the first and second switches. A PWM controller generates a switch driver control signal for controlling the switch driver circuit according to an output voltage. The switch driver circuit generates an on-time control signal for turning off the first switch when the first switch has been turned on for longer than a threshold period.

Abstract: A switch control device, a switch control method, and a converter using the same are disclosed. The converter includes: a switch; an energy transfer element that converts input energy into output energy according to a switching operation of the switch; and a switch control device that generates a first signal, which is maintained at a first level during a first interval starting from a first time at which the switch is turned on by using a feedback signal corresponding to the output energy and is then gradually lowered from the first level to the feedback signal during a second interval, and controls the switching operation of the switch by using a second signal corresponding to a current flowing at the switch and the first signal. A malfunction due to an LEC can be effectively prevented, and the converter and the converter controller can be implemented to be compact and low-priced.

Abstract: In an interleaved switching converter, a first converter including a first switch is coupled to a second converter including a second switch. A switching controller for controlling the first switch and the second switch outputs a second control signal for operating the second switch based a first control signal for operating the first switch. A phase shift between the first control signal and the second control signal is 180 degrees.

Abstract: A converter and a driving method thereof are provided. The converter can determine the output short state of the converter after the soft start is finished by using a detection signal that corresponds to an input signal while a switched is turned on and that corresponds to an output signal while the switch is turned off, so as to convert the input signal into the output signal according to a switching operation of the switch. The converter can determine the overload state of the converter by using a feedback voltage corresponding to the output signal, and terminate the switching operation when the converter is in an output short state or overload state.

Abstract: A converter control circuit applicable to various topologies of converters each employing two switching devices is disclosed. The converter control circuit includes an oscillator for generating a pulse signal and triangle-wave signal of a certain frequency, a switching control signal output unit for outputting a switching control signal to control ON/OFF of a plurality of switching devices based on a duty ratio determined from a feedback signal which is applied to a feedback terminal, a mode select signal generator for generating a mode select signal for determination of a control mode of a converter in response to the feedback signal applied to the feedback terminal, and a mode selecting unit for selecting the control mode in response to the mode select signal.

Abstract: An auto gain controller is provided. The auto gain controller includes a variable gain amplification unit configured to receive differential input signals, adjust an amplification gain based on an auto gain control voltage and output differential output signals. The auto gain controller also includes a peak detector configured to detect at least one peak value among the amplified differential output signals, a comparator configured to compare the at least one detected peak value with a reference voltage and generate a comparison signal, and a voltage adjusting circuit configured to adjust the auto gain control voltage and the reference voltage based on the comparison signal.

Abstract: The present invention relates to a quasi-resonant converter. In the quasi-resonant converter according to the present invention, a predetermined first period and a second period following to the first period are set. In the second period, a switch is turned on at a time point where voltages at both ends of the switch fall to the minimum if the second period includes the time point, and the switch is turned on at the end of the second period if the second period does not include the time point. Therefore, the switching frequency of the switch can be restricted within a predetermined range.

Abstract: A switching mode power supply includes a power supply circuit, a feedback circuit, and a switching controller. The power supply circuit includes a main switch coupled to a primary coil of a transformer, and supplies power to a secondary coil of the transformer according to an operation of the main switch. The feedback circuit generates a feedback voltage corresponding to an output voltage provided to the secondary coil of the transformer. The switching controller controls the main switch to turn off according to a sense voltage corresponding to the current flowed by the main switch. In this instance, the switching controller quickly senses the output short phenomenon by using the duty ratio of the main switch and the feedback voltage and shuts down the main switch to protect the circuit.

Abstract: In one embodiment, a switching mode power supply (SMPS) includes a rectifier for generating an input DC voltage from an input AC voltage. A switching transistor, coupled to a primary coil of a transformer, converts the input DC voltage and supplies power to a secondary side of the transformer according to an operation of the switching transistor. A switching controller receives a feedback voltage corresponding to a voltage of the secondary side of the transformer, a sense signal corresponding to current flowing at the switching transistor, and a first signal corresponding to a voltage difference between first and second electrodes of the switching transistor. The switching controller controls the turning on and off of the switching transistor. After the switching transistor is turned off, the switching controller detects and counts a number of times that a voltage level of the first signal and a reference voltage are equal.

Abstract: A switching mode power supply includes: a power supply unit that comprises a switch that is coupled to a primary coil at a primary side of a transformer for converting an input DC voltage, and that supplies power to a secondary coil and a tertiary coil at a secondary side of the transformer according to an operation of the switch; a switching controller that receives a feedback voltage corresponding to a first voltage generated in the secondary coil at the secondary side of the transformer, and receives a detection signal corresponding to a current flowing to the switch to control an on/off operation of the switch; and a feedback signal generator that receives the first voltage and the switching control signal, samples the first voltage by using first pulse strings, and generates the feedback voltage according to a level of the first voltage sampled by a first pulse in the first pulse strings, wherein a toggling time of the first pulse strings is changed in a first period for sampling the first voltage, and a

Abstract: A switching mode power supply (SMPS) and a driving method thereof are provided. The SMPS includes a power supply block that includes a first switch coupled to a first coil of a primary side of a transformer for converting an input voltage, wherein the power supply block supplies power to a second coil and a third coil of a secondary side of the transformer according to operation of the first switch; and a PWM signal generator determines a turn-on time of the first switch according to the input voltage, and the turn-on time is determined regardless of a power magnitude of an output terminal connected to the second coil. Accordingly, screen noise due to a ripple can be eliminated and stress on the switch breakdown due to excessive power input can be reduced to enable an SMPS with stable driving.