Distributed Delay-Based BIST for Mixed-Signal Circuits in Flexible Electronics
2026-07-21 • Hardware Architecture
Hardware ArchitectureEmerging Technologies
AI summaryⓘ
The authors developed a tiny and low-power testing system to check for problems in flexible electronics made with IGZO-TFTs, which are used in wearable devices. They combined two types of oscillators into one unit that uses much less space and power than older designs. Inside the system, a simple digital test monitors delays in each part of the oscillator to spot defects early. This testing method can detect most single and multiple faults while adding very little extra power use.
Flexible ElectronicsIGZO-TFTRing OscillatorVoltage-Controlled OscillatorBuilt-In Self-Test (BIST)Analog/Mixed-Signal CircuitsDefect CoverageWearable DevicesLow-Power DesignDelay Monitoring
Authors
Paula Carolina Lozano Duarte, Sule Ozev, Mehdi Tahoori
Abstract
Flexible electronics (FE) based on indium gallium zinc oxide thin-film transistors (IGZO-TFTs) are emerging for ultra-low-power wearable applications. However, lack of packaging, limited pins, and high device variability make conventional Automatic Test Equipment (ATE) impractical for testing analog/mixed-signal circuits in FE. This work presents a dual-purpose ring oscillator (RO) and voltage-controlled oscillator (VCO) serving as functional timing blocks and core structures for a distributed delay-based BIST framework. The oscillators achieve 1100x area reduction and 5600x lower power than previous IGZO-TFT designs. Lightweight digital BIST embedded within each RO stage enables stage-wise delay monitoring for defect detection. The BIST achieves 93% defect coverage for individual defects and 88% for multiple simultaneous defects, with only 3% power overhead