Maps, Inc.

National Semiconductor Corporation

Korea Institute of Science and Technology

Fairchild Korea Semiconductor Ltd.

Hyun-Ick Shin

Jong-Tae Hwang

Joon Rhee

Sang-O Jeon

Ik-Gyoo Song

Jong-Ho Lee

Dae-Ho Kim

Sung-Min Park

Hae-Weon Lee

Ki-Woong Jin

Sang-Yong Lee

Joo-Sun Kim

Hue-Sup Song

Jang-Yong You

Dong-Seuk Lee

Dong-Su Lee

Jang-Won Heo

Jong-Hoon Lee

Jae-Gon Seo

A dual band wireless power reception unit is disclosed. The wireless power reception unit according to one embodiment comprises: a first resonator; a second resonator connected to the first resonator in parallel; a single rectifier having, as an input, a node in which outputs of the first resonator and the second resonator are connected to each other in parallel; at least one switch having a first output, a second output, and an input, wherein the second output is connected to the ground; at least one capacitor connected to the second resonator in parallel, and of which one terminal is connected to the first output of the switch and the other terminal is connected to the rectifier input; and a frequency sensor sensing an input frequency from the rectifier input, and of which an output is connected to the input of the switch.

Dual band wireless power reception unit

A magnetic resonance wireless power transmission device capable of adjusting resonance frequency is disclosed. A wireless power transmission device according to an embodiment of the present invention comprises: a power amplifier for amplifying a wireless power signal using a driving frequency signal; a resonator for configuring a resonance tank and wirelessly transmitting, through magnetic resonance, the wireless power signal output from the power amplifier using a resonance frequency of the resonance tank; and a resonance control unit for controlling a duty ratio using a frequency applied to the resonator or a frequency signal generated by the resonator and adjusting the resonance frequency of the resonator.

Magnetic resonance wireless power transmission device capable of adjusting resonance frequency

An active diode having an improved transistor turn-off control method is disclosed. The active diode comprises: a comparator for comparing voltages of both ends of a parasitic diode of a transistor; and a gate driver for controlling a gate terminal of the transistor according to the comparison result of the comparator, and estimates a turn-on time of the transistor and uses the same to control the gate terminal of the transistor.

Active diode having improved transistor turn-off control method

An active diode driver for operating a switch of an active rectifier using an active diode is provided. The active diode driver may first control a soft turn-on of the switch and secondly control a hard turn-on of the switch, thereby making it possible for the switch to be softly turned-on.

Active diode driver

An active diode that features improved control of transistor turn-off is provided. Such an active diode may include a comparator to compare voltages between opposite ends of a parasitic diode, and a gate driver to control a gate terminal of the transistor according to the comparison result of the comparator. Furthermore, the active diode may further include an off-timing controller to control the transistor to be turned off at a point in time when voltages of the opposite ends of the parasitic diode turn positive. Thus, the active diode may be turned off when required.

A gate driver driving a switching device is disclosed. The gate driver includes a capacitor which is coupled to the input of the switching device. The gate drive power consumption is reduced by this additional capacitor.

Gate driver for isolated input switching device

A synchronous switch uses body-control switches to control the polarity of the parasitic device, which can be used to reduce power consumption by the parasitic device in accordance with various operating conditions. A charge-supplying device (such as a capacitor) is coupled in series between the bulk node (of the synchronous switch) and a power node (such as Vout or ground). The charge-supplying device provides power to the bulk node of the switch during reverse recovery of the parasitic device to minimize recombination time. Minimizing recombination time allows the polarity of the parasitic device to be switched more quickly (especially under low operating voltage and/or heavy load conditions), which converses more power.

Reverse recovery current assisted body-controlled switch

A method for preparing powder granules by a liquid condensation process comprising preparing a slurry by mixing powders, a binding agent and a binding agent soluble solvent, dropping the slurry to a binding agent insoluble solvent to fix the binding agent so that the binding agent can not be released to a surface of a droplet of the slurry, coagulating the droplet by solvent exchange between the soluble solvent inside the droplet and the insoluble solvent at the surface of the droplets, and separating the coagulated droplet from the insoluble solvent, drying it and completely removing a residual solvent.

Preparation of powder granules by liquid condensation process and manufacture of powder compacts thereof

Disclosed is an apparatus and a method for determining a commutation time of a three phase brushless direct current (BLDC) motor. The apparatus comprises a commutation controlling pulse generation unit receiving a phase voltage of each phase and generating a commutation controlling pulse to determine a commutation time of each phase of the motor; a first counter receiving a first commutation controlling pulse output from the commutation controlling pulse generator and counting the period of commutation controlling pulses; a memory storing one half of the counted values of the period of the first commutation controlling pulses counted by the first counter; a first comparator comparing a counting value of a period of a commutation controlling pulse provided after the first commutation controlling pulse counted by the first counter with one half of the counted values of the first commutation controlling pulses stored in the memory; and an output controller receiving the comparison result of the first comparator and outputting a switching signal to control commutation of each phase of the motor. The method comprises the steps of receiving variations of the BEMF of each phase of the motor and generating commutation controlling pulses for determining a commutation time; counting the period of the commutation controlling pulses; storing one half of counted values of the counted period of the commutation controlling pulses in a memory; counting a period of the commutation controlling pulses provided after the counted commutation controlling pulses; comparing counted number of the commutation controlling pulses input during the counting operation with the value stored in the memory; and generating a switching pulse to perform commutation of each phase of the motor when the comparison results are identical.

Growing community of inventors

Seoul, South Korea

Hyun-Ick Shin