1. Low Current Sample-and-Hold Stage

Sample-and-hold stage is necessary for quantization system to reduce the distortion, particularly in bio-sensors. Many bio-detectors detect pA-nA currents with kHz frequency. High performance current sample-and-hold stage is needed for high quality bio-detectors. In this project, we developed a sub-uW high performance current sample-and-hold stage. A design methodology is formulated to design current sample-and-hold stage for any target signal-to-noise-distortion ratio (SNDR).

2. High Performance CMOS Imaging Sensor

Bio-medical diagnostics has different requirements on imaging sensors. For example, in the application of capsule-endoscopy, a camera pill is swollen by the patient. The camera can take images along the gastro-intestinal tract, and transmits the image data out through a wireless link. Because the total transmission energy is limited by the battery in the pill, the image quality is limited by the output data rate. Therefore, CMOS imaging sensor should provide wide dynamic range, high linearity, and low output data rate. Previous CMOS imaging sensor can not achieve all the performance simultaneously. In this project, we developed a new partial quantization architecture with digital calibration, which can expand the dynamic range and improve the linearity of a CMOS imaging sensor together. As a result, the new CMOS imaging sensor architecture provides wide dynamic range, high linearity, low output data rate and high signal-to-noise ratio (SNR) at the same time. The new architecture can serve as a good solution for implantable bio-medical diagnostics.

3. CMOS Imaging Detector for Computed Tomography

CT is the leading non-invasive anatomical imaging technology. The performance of CT detector is critical to the performance of a CT system. A CT detector demands high linearity, wide dynamic range and high frame rate. Existing CT detectors are mainly designed by CCD imaging sensor. Nonetheless, CCD imager has its problems. In this project, we are designing high-performance CMOS imaging sensors to achieve the specifications for CT detectors.

4. Intra-body Communication

As more and more medical devices become implanted for cardiac monitoring, cortical/neuronal prosthesis, gastro-intestinal tract imaging, blood vessel imaging etc., intra-body communication (IBC) appears to be the promising technology for ultra-low-power data exchange for implantable devices. IBC passes modulated signals through the human man. It has potential applications in entertainment, personal data interaction, medical monitoring system and disabilities assistance. Lower power consumption can be achieved in comparison with existing wireless technology such as bluetooth, Wifi and Zigbee. In this project, we are developing effective setups to characterize the IBC channel. We are also developing the system and circuit level platform for IBC enabling.

5. Low-Power Pipelined ADC

Pipeline ADCs are widely used for applications with medium resolution (10-14 bit) and speed (MS/s), such as base-band communication and image quantization. A pipeline ADC generally includes a sample-hold front-end (SHA), a multi-bit multiplying digital-to-analog converter (MDAC), and a cascade of 1.5-bit MDACs. The bottleneck for a pipeline ADC is its power consumption. Compared to its competitors, such as SAR ADC and ADC, a pipeline ADC consumes excessive power. In this project, we are designing new pipeline ADC architecture to reduce the ADC power consumption.

6. Low-Noise Bio-Potential Detection IC

Biological cell functions through electrical pulses. The study of the cell electrical characteristics is important for pharmaceutical and bio-medical industries. Electrical characteristics of the cells can be monitored in real time by an MEA device bump-bonded to a processing IC. The cell can directly grow on the MEA. Nonetheless, it is challenging to perform high-performance processing on the weak cellular voltage signals in a large array by the CMOS IC. In this process, we are designing a multi-mode detection circuit array to process the signal with very low noise.

7. CMUT Ultrasound Transceiver

Capacitive micromachined ultrasound transducer (CMUT) is a new device, which has great potential for medical ultrasound imaging and diagnostics. Among its many advantages, tiny CMUT devices can bump-bonded to the analog IC to form large 2D array for real-time 3D ultrasound imaging. In this project, we are designing phased-array for the 2D CMUT array. We are designing transceiver for the CMUT array.