Switched Capacitor DC-DC Converter for Miniaturised Wearable Systems

Abstract

Motivated by the demands of the integrated power system in the modern wearable electronics, this paper presents a new method of inductor-less switched-capacitor (SC) based DC-DC converter designed to produce two simultaneous boost and buck outputs by using a 4-phases logic switch mode regulation. While the existing SC converters missing their reconfigurability during needed spontaneous multi-outputs at the load ends, this work overcomes this limitation by being able to reconfigure higher gain mode at dual outputs. From an input voltage of 2.5 V, the proposed converter achieves step-up and step-down voltage conversions of 3.74 V and 1.233 V for Normal mode, and 4.872 V and 2.48 V for High mode, with the ripple variation of 20-60 mV. The proposed converter has been designed in a standard 0.35 µm CMOS technology and with conversion efficiencies up to 97-98% is in agreement with state-of-the-art SC converter designs. It produces the maximum load currents of 0.18 mA and 0.36 mA for Normal and High modes respectively. Due to the flexible gain accessibility and fast response time with only two clock cycles required for steady state outputs, this converter can be applicable for multi-function wearable devices, comprised of various integrated electronic modules.

Modelling of Implantable Photovoltaic Cells Based on Human Skin Types

“…The start-up charge pump [15] or use 2-PV cells in series to boost the low voltage from the solar output 0.9 V input of the main charge pump. The 4-phases rotations series-parallel charge pump has implemented as the main circuit and presented in [16,17]. This is because this converter can supply the various voltage range of implantable applications at the load ends by only using four integrated capacitors and switches.…”

Design and Implementation of a 3D Printed Sensory Ball for Wireless Water Flow Monitoring

“…In this project, a spherical outer case is preferred to sense fluid mobility. The crux of the matter lies here: the outer case needs to be assembled as rigid as possible to keep the water out but at the same time, be able to reopen easily to make maintenance possible [10][11][12][13][14]. Here we seek to create another way of locking that is low-cost, standard, repeatable and tight.…”

Energy-Efficient Start-up Power Management for Batteryless Biomedical Implant Devices

“…This converter is designed to configure two different simultaneous regulated stable dual outputs (Vo1, Vo2) by using switch-mode regulation. Power stage network is divided into two conceptual internal networks (Net0, Net1) and boost operation will perform in Net0 while another boost output produces at Net1 [9]. Therefore, in every clock cycle, there will be two active corresponding internal outputs at (Out1-Out4).…”

“…Now turning point to the scenario of PV cell, AM 1.5G regulates light irradiance (G) as 1000 W/m2 (We assume the light propagates with a 90o incident angle and device is perpendicular to the incident light), and the ambient temperature is 300K. It should be mentioned that the transmittance of skin is set up as 20% according to the The implantation of the start-up series-parallel charge pump has presented in [11], in which the series of D-flip flops are employed to enable four phases and the ring oscillator circuit further enhance the non-overlapping to avoid charge settling and short-circuit loss [12]. These non-overlapping clocks are denoted as (ɸ1-ɸ4) in Fig.…”