On-chip Temperature Compensation with a Reference Voltage Method for CMOS Image Sensors
Y. Tai (TU Delft - Electrical Engineering, Mathematics and Computer Science)
AJP Theuwissen – Graduation committee member (TU Delft - Electronic Instrumentation)
Jaekyum Lee – Mentor (TU Delft - Electronic Instrumentation)
Rao padmakumar – Graduation committee member
P.J. French – Graduation committee member (TU Delft - Bio-Electronics)
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Abstract
This thesis presents a temperature-dependent reference control method to compensate for the temperature effect on CMOS image sensors from -40◦C to 125◦C. Recently, machine vision has been one of the most important applications for CMOS image sensors. However, the working environment and operation might generate large temperature variations and degrades the performance of CMOS image sensors. In this work, the temperature dependency of the distortion generated in the analog front-end is investigated. A mathematical model has been built to describe the relationship to its temperature dependency. Besides, a temperaturedependent reference control method with 16 different slopes is proposed. This method can control the working condition of the transistors and compensate for the change by reference current or voltage. Besides, the slope design can cover the external noise or mismatch and fulfill the compensation. Finally, it can compensate the signal distortion and prevent the settling error which could generate FPN while maintaining the noise performance. A SPICE simulation and post-simulation are performed to confirm the results of the design.