Battery management and diagnosis are crucial for the performance, efficiency, reliability, lifetime, and safety of battery-operated systems. Our battery team focuses on the modeling, simulation, and analysis of batteries based on multidisciplinary studies of electrochemistry and thermodynamics. We aim to develop a next-generation battery analysis technique that can diagnose various states of batteries in advance or in real time on battery management systems.

• Electrochemical impedance spectroscopy (EIS)-based battery diagnosis
• Artificial intelligence (AI)-based passive EIS
• On-board EIS in battery management systems
• Battery state of health (SOH) modeling based on the thermodynamic parameters
• Real-time measurement of battery entropy (∆S)
• Battery state-aware charging algorithms

Conventional radios for low-power wide-area networks (LP-WAN) adopt time-scheduled duty cycling that operates only at a pre-determined time to reduce the receiver’s standby power. This scheme is unsuitable for aperiodic, bi-directional communication or applications where real-time response is essential. Our lab focuses on the design of ultra-low-power wake-up transceivers to resolve the limitations of conventional radios, thereby reducing the standby power of the radio to 1/100 of that of the conventional LP-WAN radio while achieving a real-time response within 2 seconds. Our research on LP-WAN radios will, therefore, increase the battery life of wireless radios by 100 times compared to the existing standards.

• Frequency Band : 200 MHz – 1000 MHz, ultra-low power transceiver and wake-up radio systems for IoT devices
• Architecture : Direct conversion and sliding-IF receiver architecture

Circuits are designed and characterized for frequencies ranging from 200 MHz – 1000 MHz

• TX: High-efficiency driving amplifiers (DAs) and power amplifiers (PAs), frequency modulators
• TX/RX: Voltage-controlled oscillators (VCOs) and phase-locked loops (PLLs)
• RX: Broadband low-noise amplifiers (LNAs), mixers, baseband amplifiers, demodulators, and RF and baseband filters

It is expected that 6G services require high data-rate over Tbps to exchange a huge amount of information. Accordingly, the research on terahertz (THz) band communication system is emerging because of the ease of configuration of tens of GHz bandwidth. Our lab aims to develop low-cost, low-power and high-performance THz front-end circuits to prepare for the upcoming 6G communication.

•  THz communication systems
•  THz spectrometer systems

• THz amplifiers : power amplifiers (PAs) and low noise amplifiers (LNAs)
• THz voltage controlled oscillators (VCOs)
•  THz phased locked loops (PLLs)
•  Other blocks required for THz communication system

An electric vehicle employs a battery management system (BMS) for safe operation of batteries. For reliability purposes, a BMS should be capable of operating in extreme environmental conditions. Battery Management Integrated Circuit (BMIC) is a sub-component of BMS which includes power conversion system, V/I/T measurement system, F/V/I reference system, communication system, etc.

In the BMIC, power is supplied from 3 to 16 cells connected in series. High efficiency power conversion system with a large conversion ratio is needed to minimize the accuracy reduction of BMIC due to heat generation.

At least two separated systems are needed to meet the ASIL-D (Automotive Safety Integrity Level) requirement, which increases the production cost. For high accuracy in harsh environments with a low production cost, the voltage reference circuit should have PVT self-calibration technique.

Due to safety reasons, all conductive connections between BMICs should be DC-isolated because of different voltage potential of each BMIC. Additionally, there are a lot of electromagnetic emission sources in a vehicle. Communicating through a wireline system across this harsh environment is challenging, so it usually leads to a high-power consumption & cost. Wireless communication is getting popular as a solution for BMIC communication, but establishing a reliable wireless communication link is extremely hard to achieve under severe environmental conditions. The research direction for this project aims to develop a BMS which provides a solution to the above-mentioned limitations.

• Power converter for EV BMIC
• Wireline and wireless communication system for EV BMS
• Self-calibrated reference system (F, V, I) with high accuracy for EV BMS
• Mobile device charger for EV

• Power converters: wide input range buck converter, high power four-switch buck-boost converter
• Self-calibrated oscillator
• High speed EMI-tolerant and isolated communication transceiver
• Infrared Optical TIA