Biomedical Circuits and Systems III

15:00 – A Wide Range tunable Active Band Pass Filter using Flexible Oxide TFTs Technology

This work presents a novel second order Band Pass Filter (BPF) designed using an all enhancement unipolar(n-type) amorphous indium gallium zinc oxide (a-IGZO) thin-film transistor (TFT) technology, compatible with flexible substrates. This BPF utilizes a tunable active inductor based on a transconductance-C (Gm-C) topology. The circuit deploys an active inductor. BPF consists of an input transconductance stage (gm), a frequency-tunable LC tank, and an output buffer stage for Q-factor enhancement. The center frequency and Q-factor of the BPF can be independently tuned via control voltage, making it suitable for a wide range of bio-medical applications. Post-layout simulation results indicate that the BPF achieves a tuning range of center frequency from 100 Hz to 1 kHz by adjusting the bias voltage from 2.3 V to 2.8 V and shows a power consumption of 75 μW (at 100 Hz) and 80 μW (at 1 kHz), respectively with a supply voltage (VDD ) not exceeding 4 V. Moreover, the BPF exhibits a maximum and minimum insertion loss of -3.8 dB and 5.1 dB with a 3-dB bandwidth of around 300 Hz. This circuit occupies a total active area of 0.02 mm². These parameters demonstrates that the proposed BPF can find potential applications in energy-efficient wearable and biomedical devices.

15:20 – Hardware-Efficient Rwave Delineation by AdEx Encoded Lead II ECG: No Filters, No Preprocessing

A real-time, time-domain QRS detection system is developed that encodes rawECG signals using a single threshold Adaptive Exponential (AdEx) neuron model, generating positive spikes. The resulting Inter-Spike Interval (ISI) variations effectively capture the steep temporal changes around the Rpeak, allowing for robust discrimination from noise and other waveform components. The system is validated on a Zynq 7000 Zed Board and synthesized in Cadence 45 nm technology, achieving a low power consumption of 0.38 µW and a compact area of 0.0154mm2. It attains an accuracy of over 97% for noisy ECG signals without any preprocessing, demonstrating its suitability for ultra-low-power, real-time, always-on biomedical applications.

15:40 – 40-Channel, Boxcar-Integrator System for High-Resolution Pump-Probe Optical Spectroscopy

This work presents a multichannel platform specifically designed for broadband Pump-Probe spectroscopy, an advanced optical technique largely used in material science and biology to study ultrafast phenomena on the fs-ps timescale. While existing spectrometers are available on the market, they are constrained to operating with laser pulses in the tens of kHz range, leading to long acquisition times. This system aims to overcome theese limitations exploiting a CMOS boxcar averager ASIC, which allows the use of lasers with a repetition frequency in the MHz range thanks to the switching capacitor technique. By reducing signal acquisition times exploiting faster lasers and the simultaneous acquisition of 40 wavelengths with parallel analog-digital signal processing, the platform achieves a 0.3 ppm resolution in 2s acquisition time, better than current state-of-the-art solutions.

16:00 – A Switched-VCII with Track and Hold Functionality

In this paper, a CMOS current-mode Track and Hold circuit with voltage output is presented. The proposed circuit is based on a Switched Second-Generation Voltage Conveyor (VCII), which enables efficient sampling and stabilization of analog signals. Designed using a standard 150 nm CMOS technology and powered at 3.3 V, the circuit leverages the intrinsic properties of the VCII—namely its current and voltage buffering capabilities— to achieve a low current-input impedance of 41 Ω, a high voltage input impedance of 1.3 MΩ, a low voltage-output impedance of 3.8 kΩ, and effective voltage tracking. A switched-biasing technique is employed to implement track-and-hold functionality. Simulation results confirm the correct T/H behavior with biomedical input signals, such as an ECG waveform. The circuit demonstrates robust performance across process-voltage temperature (PVT) corners, validating its suitability for low frequency, low-voltage analog front-end applications, particularly in biomedical and sensor interface systems.

16:20 – Bulk- Current-Regulated Rectifier for Battery-less Ultrasound-Powered Implantable Medical Devices

A regulated passive rectifier is introduced in this paper, specifically designed for battery-less, ultrasound-powered implantable medical devices. The rectifier exploits a bulk-driven amplifier and modulation of the bulk current of the p-type transistors to regulate the output voltage. The proposed solution is implemented in 180-nm standard CMOS process technology and validated through post-layout simulations. Comparison with previous art shows a significant improvement of the performance thanks to its nA-range quiescent current consumption, low area and low-voltage/low-power operation capabilities, well-fitting low-invasiveness and high-efficiency fully-harvested implantable devices.