Session 14: FHE Applications II
Flexible Near Field Communication Sensor Labels Built on a Printed Dopant Polysilicon TFT Platform
Wednesday, June 21, 2017
1:30 PM - 1:55 PM
Thin, highly flexible Near Field Communication (NFC) wireless sensor labels with 3 bit resolution are demonstrated. A Flex-Hybrid technique is employed that allows for integration of multiple components on a plastic substrate with a low thermal budget assembly process. At the heart of the system is a time-to-digital converter (TDC) based analog-to-digital converter (ADC) that communicates through an NFC RF interface. The 3-bit ADC and the NFC interface die were designed on ThinFilm’s printed dopant poly-Silicon (PDPS) thin film transistor(TFT) technology fabricated on a stainless steel substrate. The ADC input is designed to interface with light, humidity, or temperature sensors with minimal configuration changes. The TDC converts changes in current, resistance or capacitance into frequency through an on-chip oscillator. An on-chip reference frequency is generated and the ADC codes are calculated through a defined relationship. Calibration is used to improve the robustness of the architecture against mismatch, variation in passive components as well as variation in the slope of the different sensors. The NFC chip uses a 128 bit tag-talks-first (TTF) protocol that enables the readout through an Android based mobile device. A critical component of the system is for the two dies to overcome noise coupling and communicate through this substrate. Measurement results demonstrating the feasibility of the architecture are presented. This paves the way for low cost, robust, disposable wireless electronics that power the Internet of Everything. This work was enabled by a grant from Flextech for a project led by ThinFilm Electronics titled “Flexible, Dual Use, Active Sensor Labels”.
Soumya Krishnamoorthy is a senior design engineer with Thin Film Electronics and her interests span analog and mixed-signal design for sensors as well as RF transceiver design. Prior to ThinFilm, she worked at Quantance Inc. and NanoAmp solutions developing envelope tracking systems for 4G LTE and 3G transceivers in CMOS technology. Soumya has a PhD in Electrical Engineering from the University of Maryland at College Park.
Thin Film Electronics