Samsung Electronics Co., Ltd.

Fairchild Korea Semiconductor Ltd.

Dae-Woong Cho

Dong-Keun Kim

Sung-Woo Kim

Sung-Woo Lee

Ji-Hoon Park

Hyoung-seok Oh

Kyung-Oun Jang

Hyeong-Gwon Kim

Jung-wook Heo

Min-Woo Lee

Sang-Hee Kang

Kwang-Chan Lee

Sung-Won Yun

A magnetic secure transmission system includes an inductor, a switching circuit connected to the inductor, and a control circuit. The control circuit controls the switching circuit to adjust a level of a current in the inductor by a first amount over a data transmission period, such that the inductor emits a magnetic pulse including a first magnitude during the data transmission period. The control circuit controls the switching circuit to adjust the level of the current in the inductor such that the level of the current is increased and decreased repeatedly by a second amount between two different levels during a data non-transmission period, and the inductor emits a magnetic pulse including a second magnitude during the data non-transmission period. The second amount is less than the first amount, the first magnitude is greater than a threshold value and the second magnitude is less than the threshold value.

Magnetic secure transmission (MST) device, MST system and controller including the same

A magnetic secure transmission (MST) system includes a switching circuit, an inductor, and a control circuit. The control circuit is configured to control the switching circuit to adjust a level of current in the inductor. The inductor current may be adjusted by a first amount over a data transmission period such that the inductor emits a magnetic pulse including a first magnitude. The inductor current may be kept constant during a first sub-period of a data non-transmission period and may be changed by a second amount at a constant slope during a second sub-period of the data non-transmission period, such that the inductor emits a magnetic pulse including a second magnitude during the second sub-period of the data non-transmission period. The second amount is less than the first amount. The first magnitude is greater than a threshold value. The second magnitude is less than the threshold value.

Magnetic secure transmission device, electronic device and mobile system including the same

The present invention relates to a thermal shutdown unit, a switch controller including the same, and a method controlling a thermal shutdown protection operation. The present invention determines the operation state of an SMPS to vary a reference temperature for controlling a thermal shutdown protection operation according to an operation state of the SMPS.

Thermal shutdown unit, switch controller including the same, and control method of thermal shutdown protection operation

The present invention relates to a power supply device generating an output power by using an AC line voltage generated through rectification of an AC input, and a driving method thereof. The power supply device controls the switching operation of the power switch by using a sensing voltage corresponding to the drain current flowing to the power switch and the feedback voltage corresponding to the output voltage. The power supply device controls the feedback current every switching cycle to generate a threshold voltage, and compares the sensing voltage and the threshold voltage to control the turn-off of the power switch. The feedback current includes the first current to generate the feedback voltage, and the threshold voltage follows a curved line waveform in which the increasing slope is decreased during the switching cycle.

Power supply device and driving method thereof

Growing community of inventors

Seoul, South Korea

Dae-Woong Cho