Samsung Electronics Co., Ltd.

Jeongseok Seo

Doohee Hwang

Seungwoo Ryu

Kwanghyun Kim

Yihwa Her

Chikook Kim

A method of operating a memory device, the method includes periodically receiving a refresh command from a host, determining whether a target row address is activated during a predetermined period of time, and skipping a refresh operation on a word line corresponding to the target row address when the target row address is activated, and transmitting, to the host, a refresh skip signal corresponding to the word line on which the refresh operation is skipped, or performing, in response to the refresh command, a refresh operation on a word line corresponding to the target row address when the target row address is not activated.

Memory device, memory system including memory device, and method of operating memory device

A semiconductor memory device includes an external resistor provided on a board and a plurality of memory dies mounted on the board, designated as a master die and slave dies. The memory dies are commonly connected to the external resistor. The master die performs a first impedance calibration operation during an initialization sequence of the semiconductor memory device and stores, in a first register set therein, first calibration data, a first voltage and a first temperature. Each of the slave dies, after the first impedance calibration operation is completed, performs a second impedance calibration operation during the initialization sequence and stores, in a second register set therein, second calibration data associated with the second impedance calibration operation and offset data corresponding to a difference between the first calibration data and the second calibration data.

Semiconductor memory devices and memory systems including the same

A mobile device is provided. The mobile device includes a battery, a Subscriber Identification Module (SIM) card, and a control unit. The mobile device transmits residual power information of the battery to a base station, and receives a SIM card polling cycle determined on the basis of the residual power information from the base station. Thereafter, the mobile device periodically determines the state of the SIM card in the received SIM card polling cycle.

Mobile device having SIM card, base station connected thereto, and battery management method thereof

A method and a portable terminal for reducing standby power of a portable terminal which performs paging according to a set paging interval are provided. The method includes determining whether a Subscriber Identification Module (SIM) card polling interval arrives during a sleep mode of the portable terminal and synchronizing the SIM card polling interval with the set paging interval when the SIM card polling interval arrives.

Growing community of inventors

Seoul, South Korea

Jeongseok Seo