Ning Li: Designing integrated circuits for the future

A principal research engineer at SRI’s Advanced Imaging Lab shares the challenge — and the joy — of building products that benefit the world.

Ning Li joined SRI’s Advanced Imaging Lab during the COVID-19 pandemic. In his time here as a principal research engineer, Li has been a part of several cutting-edge projects – designing high-performance imaging sensors that improve digital image processing capabilities. Here, Li discusses his quest to be a part of meaningful work that impacts the world:

I became very interested in electronics at a young age, and I started building AM radios and audio amplifiers but didn’t actually study electronics for many years. My father was a mechanical engineer and my mother was a doctor, so I decided to study biomedical engineering. I ended up in that major until the beginning of my PhD in plant science and physiology at Oregon State University. I was focused on applying spectroscopic and fluorescence imaging to capture the photosynthesis of plants, and I ended up taking several courses in electrical and computer engineering.

It turned out that even though I’d focused on biology for so many years, I liked the study of microelectronics a lot more; it was very challenging, but I found it so interesting and rewarding. I ended up also getting a master’s degree in microelectronics.

Driven by my interest in integrated circuits design, I worked in Silicon Valley for many different companies for more than 25 years. At the beginning of Wi-Fi chipsets, I was at Broadcom, where my team delivered a first-generation Wi-Fi solution in a single chip that only cost about $2. The next year, I led a team that delivered a chip that successfully integrated many additional smaller components. Years later, I joined Qualcomm, where I worked as a transmitter lead for a project involving a challenging 4×4 MIMO chip.

I came to SRI during the COVID-19 pandemic; I wanted to work on more meaningful projects and explore cutting-edge technologies available here. Today, I work with the Advanced Imaging team at SRI’s Princeton, N.J., campus as an analog circuit designer for high-performance imaging sensors. One of the key components in these imaging sensors is the analog to digital converter (ADC), which converts the image signal to a digital signal so that it can be processed digitally and stored in digital memory. As demand increases for faster and more precise sensors that have higher resolution and use less power, the ADC remains one of the most challenging tasks for designers like me.

Since I joined SRI, I have worked on several interesting projects; one of them is the Lightning Imaging Sensor. It’s designed to measure the amount, rate, and radiant energy of lightning during both day and night. It’s very challenging because the image sensor requires very high frame rate, large pixel array, and high dynamic range at the same time.

I think the future of this field is exciting. There’s interdisciplinary work being done in biology, the medical device field, and the integrated circuit design that has the potential to create exciting new products. SRI offers me the unique opportunity to work on projects that have direct, positive impacts on society and the world.

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