Low power, low area, analog blink restoration system with auto sleep mode for unilateral facial paralysis patients

Abstract

Functional Electrical Stimulation is considered as one of the potential solutions for restoring the functionality of orbicularis oculi (a muscle that is responsible for eye-lid closure) in the patients suffering from Bells palsy. In this paper, we propose a synchronized blink function restoration system, wherein, the muscular activity of the healthy orbicularis oculi is sensed using EMG electrodes and a corresponding triggering pulse is provided to the non-functional muscle almost instantaneously. In this paper, we present the design of a low power blink restoration system comprising only low power analog blocks. The noise cancellation and filtration which typically is carried out in digital domain is replaced with a simple analog architecture. This resulted in a two fold reduction in power and more than hundred fold reduction in area. Furthermore, the designed system takes care of any false positives due to motion artifact. A simple mono-stable system based auto sleep mode is implemented to save power when the system is not in use. This analog blink restoration system designed in UMC 180nm CMOS technology has a Pre-amplifier gain of 20dB at 270Hz to 470Hz, CMRR > 70dB, input referred noise of less than 2 μVrms. It consumes power of 6 μW at 1.2V supply voltage and an area of 0.095 mm2.