- This event has passed.
ESE PhD Thesis Defense: “Low Noise and Low Power Front-end Circuit Design for Bio-Signal Recordings”
May 13 at 3:00 PM - 5:00 PM
Bio-signals in living objects are the signals thatcarry physiological information from one part of the body to another. Studying bio-signals can extract data that maps health status or body activities for medical purposes. Implantable and wearable devices of small volume for measuring different bio-signals are desired for medical applications where the devices measure the signals with further processing to provide feedback for diagnosis and treatment. Bio-signals produced by the body usually have a small amplitude requiring low noise and low power analog front-end amplifiers and signal processing circuitry.
This talk will focus on low noise and low power readout circuits for magnetic sensing systems to acquire bio-magnetic fields. Compared to bio-electrical recordings, bio-magnetic sensing is non-invasive and non-contact. PCB-based readout electronics for strain modulated multiferroic sensors with a bandwidth of 3.4 kHz and a magnetic noise floor at 1 kHz of 98.5 pT/√Hz is implemented for understanding the circuit and the sensor noise models for modulated multiferroic sensor-readout systems. To reduce the power consumption, an ASIC readout circuit in 180 nm CMOS for the sensor is designed and implemented. By utilizing a demodulator first architecture, measurements for the sensor-readout system demonstrate a 127 pT/√Hz magnetic noise floor at 1 kHz and a low power consumption of 5.9 mW. To further improve the noise performance at low frequencies, readout circuit in BiCMOS and a differential structure are implemented to achieve a magnetic noise floor of 85 pT/√Hz at 1 kHz, and 300 pT/√Hz at 10 Hz with a power consumption of 5.6 mW. In addition, a low intermediate frequency (low-IF) demodulation readout circuit is implemented and measured to eliminate the 1/f flicker noise and realizes a noise floor of 722 pT√Hz at 1 Hz with the power consumption of 2.9 mW. The noise and power consumption that the magnetic sensing systems have achieved are significantly lower than alternative magnetic sensor systems of similar volume, which outlines an excellent solution for low-power, low-noise, wearable, on-body sensing in the future.
Yujia Huo
ESE Ph.D. Candidate
Yujia Huo is a current PhD candidate in Electrical Engineering at the University of Pennsylvania under Dr. Troy Olsson. Her research interests are low-noise and low-power analog-integrated circuit design for implantable and wearable devices in biomedical applications, including neural recording amplifiers and the readout circuit for the bio-magnetic sensor. She received the B.S. degree in electrical engineering from the University of Massachusetts Amherst, Amherst, MA, USA, in 2018.