Samsung Electronics Co., Ltd.

Dongguk University Industry-academic Cooperation Foundation

Jae-Jung Park

Min-Kyu Song

Kyu-Ik Cho

Ji-Yong Kim

Dae-Yun Kim

Yeon-Seong Hwang

A read-out circuit of an image sensor includes a ramp signal generator, a bias voltage generator and a conversion circuit. The ramp signal generates a ramp signal that linearly varies at a constant slope. The bias voltage generator generates a bias voltage based on a power supply voltage having a first noise component. The conversion circuit generates a reference voltage based on the bias voltage and the ramp signal, and performs an analog-to-digital conversion on an analog signal from a pixel to generate a digital signal corresponding to the analog signal. The analog signal has second noise component. The bias voltage generator adjusts an alternating current component included in the bias voltage such that a magnitude of a third noise component added to the reference voltage is substantially the same as a magnitude of the second noise component.

Read-out circuits of image sensors and image sensors including the same

Provided are a ramp signal calibration apparatus and method and image sensor including the apparatus. The apparatus includes: an analog-to-digital converter (ADC) including a trimmable transistor having a gain value that varies according to stored data, and configured to receive a ramp signal in a state where the gain value is a first gain value, and to output first and second output signals; a subtractor configured to calculate a difference between the first and second output signals; a digital comparator configured to compare the difference with a reference value and to determine whether a slope of the ramp signal has changed; and a counter configured to change the stored data based on whether the slope of the ramp signal has changed, wherein when the counter changes the data, the first gain value of the trimmable transistor is changed to a second gain value according to the changed data.

Ramp signal calibration apparatus and method and image sensor including the ramp signal calibration apparatus

Growing community of inventors

Hwaseong-si, South Korea

Jae-Jung Park