CenBRAIN’s Two New Publications in IEEE APCCAS’22

Paper #1 Titled “A 97 fJ/Conversion Neuron-ADC with Reconfigurable Sampling and Static Power Reduction” and Paper #2 Titled“Compact Power Front-end Management for Wireless Supply of Multi-voltages to Neuromodulators”. These two contributions were presented in the 2022 IEEE Asia Pacific Conference on Circuits and Systems, where Professor Mohamad Sawan was the General Chair. Congratulations to both authors and all co-authors for these excellent achievements.

Paper #1’s Abstract

A bio-inspired Neuron-ADC with reconfigurable sampling and static power reduction for biomedical applications is proposed in this work. The Neuron-ADC leverages level-crossing sampling and a bio-inspired refractory circuit to compressively converts bio-signal to digital spikes and information-of-interest. The proposed design can not only avoid dissipating ADC energy on unnecessary data but also achieve reconfigurable sampling, making it appropriate for either low power operation or high accuracy conversion when dealing with various kinds of bio-signals. Moreover, the proposed dynamic comparator can reduce static power up to 41.1% when tested with a 10 kHz sinusoidal input. Simulation results of 40 nm CMOS process show that the Neuron-ADC achieves a maximum ENOB of 6.9 bits with a corresponding FoM of 97 fJ/conversion under 0.6 V supply voltage.

Fig.1: System architecture: (a) Floating-window LC-ADC, (b) Fixed-window LC-ADC, (c) The proposed Neuron-ADC.

Paper #2’s Abstract

Obstructive sleep apnea is a common disease that affects almost 1 billion people worldwide. If OSA is not treated promptly, it significantly influences patients’ health-related quality of life, increasing morbidity and mortality and burdens social and psychological implications. Among available treatments (continuous positive airway pressure (CPAP), oral appliance, adenotonsillectomy, weight loss, hypoglossal nerve stimulation (HGNS), maxillomandibular advancement), HGNS shows a solid alternative to treat patients with OSA. However, the state-of-the-art hypoglossal nerve has some limitations, like invasive area volume and single-directional stimulation. Based on this, we present a CMOS power management module (PMM) implemented to deliver three DC supply voltages for powering various building blocks of an implantable medical device. This PMM includes an active rectifier, bandgap reference (BGR) circuit, and three independent low-dropout (LDO) voltage regulators. The input voltage of this PMM is a sinusoidal wave form that reaches a maximum of 2.6 V; this is derived from a power source placed outside the body through a wireless power transfer link connected to the rectifier. The three delivered DC output voltages are 1.24 V, 1.86 V, and 3.08 V. Post layout output simulation results indicate values of 1.24 V, 1.82 V, and 3.09 V, thus meeting the expected circuit simulation results. Corners, including process and Monte Carlo, were analyzed. Compared with the replica-biased loop, which has a small output voltage range with a central output to generate the other three outputs, this integrated PMM utilizing three independent LDOs has a more fantastic output voltage range. The design also meets the small-size and low-power consumption requirements and can be used to prevent obstructive sleep apnea.

Fig.1:Block diagram of the global breathing recovery implantable system

Fig.2: Professor Sawan, the chair of 2022 APCCAS, offered an opening speech to wish the conference success.