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Implantable medical devices are being used in the treatment of a growing
number of pathologies. Microelectronics is an essential tool for the
development of these devices especially novel applications. An important
aspect of the design, is the capability of controlling electrical stimuli
delivered to biological tissue.
In this work, three diff...
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Over the past three decades, the exponential growth of the microelectronics industry has been enabled primarily by continuous scaling of dimension reduction of metal-oxide-semiconductor field-effect transistor (MOSFET). The inherent benefits of MOSFET scaling are the speed improvement and energy reduction associated with a binary-logic transition....
Citations
... 4. Switch: This is used to connect the microcontroller to the battery and the capacitor. When the device is not charging to prevent the battery from powering the charging unit and dissipating the energy faster, we use this device [29]. 5. Microcontroller and timer: This device counts and sends signals to the microcontroller to determine when the capacitor goes off and the battery comes on. ...
The need for medical devices to be planted into living organisms to perform the function of a dysfunctional body part is increasing by the day. Most of these devices require power supply of some sort to function appropriately. The supply can be taken care of by batteries but the batteries have a life span which will never be long enough, especially if the implant is in a human. This will mean that every time the battery dies the device will have to be brought out and the batteries changed. This paper seeks to explore the existing energy storage capacities for a wireless setup. The addition of a supercapacitor to the battery or replacement in the power pack was simulated and analyzed. Then, a proffered solution which is introducing a microcontroller to determine the switching between battery and super capacitor was proposed. Also some level of communication and control of the implant by the external circuit through the capacitor.
... Some circuit solutions have previously been reported in [8]- [10]. The main limitation of the over-voltage protection control loop presented in [8], [9] is that the control loop creates a current path from the switch input node to the ground, though drawing some current from point A (Fig.1 recording phase. ...
... Some circuit solutions have previously been reported in [8]- [10]. The main limitation of the over-voltage protection control loop presented in [8], [9] is that the control loop creates a current path from the switch input node to the ground, though drawing some current from point A (Fig.1 recording phase. Taking into account that the switches ϕ a and ϕ c are open during the recording phase, the additional non-compensated current can flow through the tissue. ...
In this paper a novel high-voltage switch with gate-source overvoltage protection is presented for use in high voltage bidirectional neural interfaces. The proposed switch can toleratethe voltage difference up to 120V between its terminals. The control circuit guarantees the operation of HV transistors in the Safe Operation Area (SOA) by use of the proposed switched voltage follower. The switch can be controlled with low voltage control signals compatible with standard CMOS logic levels. Thesimulation of the switch performance was carried out with AMS HV 0.35μm Design Kit.
... First, it is possible to increase significantly the width of the device, e.g. integrated in 0.6µm XT06 CMOS technology power switches measured up to 40000µm/3µm and the measured on resistance was <5 Ω [Szollosy10]. Secondly, the gate voltage of the switch can be slightly increased by slight redesigning of the level shifter. ...
Vibration energy harvesting is a relatively new concept that can be used in powering micro-scale power embedded devices with the energy of vibrations omnipresent in the surrounding. This thesis contributes to a general study of vibration energy harvesters (VEHs) employing electrostatic transducers. A typical electrostatic VEH consists of a capacitive transducer, conditioning electronics and a storage element. This work is focused on investigations of the reported by MIT in 2006 auto-synchronous conditioning circuit, which combines the diode-based charge pump and the inductive flyback energy return driven by the switch. This architecture is very promising since it eliminates precise gate control of transistors employed in synchronous architectures, while a unique switch turns on rarely. This thesis addresses the theoretical analysis of the conditioning circuit. We developed an algorithm that by proper switching of the flyback allows the optimal energy conversion strategy taking into account the losses associated with the switching. By adding the calibration function, the system became adaptive to the fluctuations in the environment. This study was validated by the behavioral modeling. Another contribution consists in realization of the proposed algorithm on the circuit level. The major design difficulties were related to the high-voltage requirement and the low-power design priority. We designed a high-voltage analog controller of the switch using AMS035HV technology. Its power consumption varies between several hundred nanowatts and a few microwatts, depending on numerous factors - parameters of external vibrations, voltage levels of the charge pump, frequency of the flyback switching, frequency of calibration function, etc. We also implemented on silicon, fabricated and tested a high-voltage switch with a novel low power level-shifting driver. By mounting on discrete components the charge pump and flyback circuit and employing the proposed switch, we characterized the wideband high-voltage operation of the MEMS transducer prototype fabricated alongside this thesis in ESIEE Paris. When excited with stochastic vibrations having an acceleration level of 0.8 g rms distributed in the band 110-170 Hz, up to 0.75 $\mu$W of net electrical power has been harvested.
