Ultra low power analog-to-digital converter for medical devices and wireless sensor nodes

The novel converter design decreases the total power consumption of an implantable 100-channel neural recording microsystem by more than 20%, reducing the patient's exposure to electromagnetic radiation in the brain tissue when powered wirelessly during the data acquisition of complex brain activity for medical purposes. The converter can also prolong the battery life of other wearable and implantable medical devices and wireless sensor nodes. The ability to extend the battery life and reduce the electromagnetic radiation exposure from implantable devices will significantly reduce the patient's cost, risk and invasiveness of the surgical procedures involved. Neuroprosthetics, which serve to restore motor functions in paralysed patients due to impaired nervous systems, can potentially benefit from IME's low power ADC technology.

Elaborating on the research breakthrough, Dr Cheong Jia Hao, the IME scientist who conceptualised and designed the converter integrated circuits (ICs), said, "The ADC employs a tri-level switching scheme to achieve an elegant and simplified digital logic design. By reducing the capacitor charging voltage and the number of complex arithmetic steps in each data conversion cycle, we can boost the energy efficiency to just 19.5 fJ per conversion step, which contributes to significant total power savings without sacrificing data resolution and affecting other hardware features." The converter is fabricated with 0.18 micrometre CMOS processes, a mature standard processing technology for large volume production.

Professor Dim-Lee Kwong, Executive Director of IME, said, "IME's data converter is in synergy with industry's roadmap to drive energy efficient and sustainable solutions. The power saving highlight in the new technology can also be harnessed for applications that require intensive data conversion and where ultra low power consumption is paramount. The ultra low power converter will become one of the key elements in emerging wireless sensor networks, sensor clouds, and sensor fusion for various important applications such as environmental monitoring, industrial monitoring and control, green buildings, smart transportation, and e-health."