Abstract: An interface circuit includes: a buffer circuit configured to receive an input signal and to generate an output signal having a delay time, the delay time being determined based on a current level of a bias current and a voltage level of a power supply voltage; and a bias generation circuit configured to vary a voltage level of a bias control voltage so that the delay time is constant by compensating for a change in the voltage level of the power supply voltage, the bias generation circuit being further configured to provide the bias control voltage to the buffer circuit.

Abstract: An apparatus for estimating biological information of a user may include a light source configured to emit light to an object of the user; an image sensor comprising a pixel array, and configured to acquire successive image frames by detecting light scattered or reflected from the object of the user; and a processor configured to: select a predetermined number of pixel-rows from among pixel-rows of the image sensor, detect signal intensities in the predetermined number of pixel-rows for each image frame of the successive image frames, correct the signal intensities, combine the signal intensities for each image frame of the successive image frames based on correcting the signal intensities, acquire a photoplethysmogram (PPG) signal based on combining the signal intensities, and estimate the biological information of the user based on the PPG signal.

Abstract: An interface circuit includes: a buffer circuit configured to receive an input signal and to generate an output signal having a delay time, the delay time being determined based on a current level of a bias current and a voltage level of a power supply voltage; and a bias generation circuit configured to vary a voltage level of a bias control voltage so that the delay time is constant by compensating for a change in the voltage level of the power supply voltage, the bias generation circuit being further configured to provide the bias control voltage to the buffer circuit.

Abstract: An apparatus for estimating biological information of a user may include a light source configured to emit light to an object of the user; an image sensor comprising a pixel array, and configured to acquire successive image frames by detecting light scattered or reflected from the object of the user; and a processor configured to: select a predetermined number of pixel-rows from among pixel-rows of the image sensor, detect signal intensities in the predetermined number of pixel-rows for each image frame of the successive image frames, correct the signal intensities, combine the signal intensities for each image frame of the successive image frames based on correcting the signal intensities, acquire a photoplethysmogram (PPG) signal based on combining the signal intensities, and estimate the biological information of the user based on the PPG signal.

Abstract: A memory device includes a first on-die termination circuit, a second on-die termination circuit, a voltage generator, and a code generator. The first on-die termination circuit may correspond to a data input buffer. The second on-die termination circuit may correspond to a command/address buffer. The voltage generator may generate a reference voltage. The code generator may generate a resistance calibration code of a selected one of the on-die termination circuits in response to the reference voltage. The reference calibration code may calibrate a resistance value of the selected on-die termination circuit.

Abstract: A memory device includes a first on-die termination circuit, a second on-die termination circuit, a voltage generator, and a code generator. The first on-die termination circuit may correspond to a data input buffer. The second on-die termination circuit may correspond to a command/address buffer. The voltage generator may generate a reference voltage. The code generator may generate a resistance calibration code of a selected one of the on-die termination circuits in response to the reference voltage. The reference calibration code may calibrate a resistance value of the selected on-die termination circuit.

Abstract: An infrared detector may be provided that includes: a micro-bolometer active cell which detects infrared and outputs a current signal; and a reference cell which includes a plurality of connected warm cells having the same structure and electrical characteristics as those of the micro-bolometer active cell, has the same electrical resistance value and average self-heating amount as those of the micro-bolometer active cell, and generates a reference current signal for the micro-bolometer active cell.

Abstract: An infrared detector may be provided that includes: a micro-bolometer active cell which detects infrared and outputs a current signal; and a reference cell which includes a plurality of connected warm cells having the same structure and electrical characteristics as those of the micro-bolometer active cell, has the same electrical resistance value and average self-heating amount as those of the micro-bolometer active cell, and generates a reference current signal for the micro-bolometer active cell.