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PhD Oral Preliminary Exam – Hyunkyu Ouh

New Architectures and Circuits for CMOS Optical Detectors

My research focuses on novel architectures for CMOS optical detectors. First of all, I presented an approach for combining linear and single-photon avalanche diode operation in a single pixel to enhance low-light dynamic range of a photodetector array. Pulse frequency modulation and avalanche pulse counting provide in-pixel digitization for both operation modes, enabling full parallel measurement across the array. An 8 x 8 array architecture is fabricated in standard 180 nm CMOS and demonstrates 85 dB optical dynamic range and a maximum low-light frame rate of 130 Hz.

Secondly, I also presented a new approach for applying orthogonal code-division multiplex encoding to current-mode sensor arrays with analog-domain encoding directly in the column readout circuitry, which enables simultaneous readout for multiple sensors. The approach is applied to a 8 x 16 array of CMOS-integrated photodetectors and implemented in a general purpose 180 nm CMOS process. The sensor array demonstrates 63 dB SNR with an array-wide sampling rate of 100 Hz with 16-channel encoding, an improvement of more than 12 dB compared with time-division multiplexing at the same sampling rate. This work represents the first reported code-division multiplexed sensing architecture with analog-encoding front end, and the orthogonal coding scheme is broadly applicable to electronic current-mode sensor arrays for physical, chemical, and biological sensing applications without requiring sensor input encoding.

Major Advisor: Matthew Johnston
Committee: David Allstot
Committee: Un-Ku Moon
Committee: Arun Natarajan
GCR: William Warnes

Monday, November 5 at 2:00pm to 4:00pm

Kelley Engineering Center, 1007
110 SW Park Terrace, Corvallis, OR 97331

Event Type

Lecture or Presentation

Event Topic


College of Engineering, Electrical Engineering and Computer Science
Contact Name

Calvin Hughes

Contact Email

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