CDS CIRCUIT, OPERATING METHOD OF THE SAME, AND IMAGE SENSOR INCLUDING CDS CIRCUIT

• Main Authors: CHOI YONG-SUK, LEE HYEOK-JONG
• Format: Patent
• Language: English; Japanese
• Published: 04.03.2022
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; PICTORIAL COMMUNICATION, e.g. TELEVISION

To provide a CDS (Correlated Double Sampling) circuit, an operating method of the same, and an image sensor including the CDS circuit.SOLUTION: A CDS circuit includes: a first comparator that operates on the basis of a first bias current during a first period and a fourth period in which pixels operate in a low conversion gain mode, and compares pixel voltages output from the pixels with a ramp signal; and a second comparator that operates on the basis of a second bias current during a second period and a third period in which pixels operate in a high conversion gain mode, and compares the pixel voltages output from the pixels with the ramp signal. The first comparator operates on the basis of a third bias current lower than the first bias current during the second period and the third period. The second comparator operates on the basis of a fourth bias current lower than the second bias current during the first period and the fourth period.SELECTED DRAWING: Figure 4 【課題】ＣＤＳ（Correlated Double Sampling）回路及びその動作方法、並びにＣＤＳ回路を含むイメージセンサを提供する。【解決手段】ピクセルがローコンバージョンゲインモードで動作する第１期間及び第４期間に、第１バイアス電流に基づいて動作し、ピクセルから出力されるピクセル電圧をランプ信号と比較する第１比較器と、ピクセルがハイコンバージョンゲインモードで動作する第２期間及び第３期間に、第２バイアス電流に基づいて動作し、ピクセルから出力されるピクセル電圧をランプ信号と比較する第２比較器と、を含み、第２期間及び第３期間に、第１比較器は、第１バイアス電流よりも低い第３バイアス電流に基づいて動作し、第１期間及び第４期間に、第２比較器は、第２バイアス電流よりも低い第４バイアス電流に基づいて動作するＣＤＳ回路である。【選択図】図４