Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
IEEE Trans Biomed Circuits Syst. 2012 Feb;6(1):1-14. doi: 10.1109/TBCAS.2011.2166072.
In this paper, we present a novel energy-efficient electrode stimulator. Our stimulator uses inductive storage and recycling of energy in a dynamic power supply. This supply drives an electrode in an adiabatic fashion such that energy consumption is minimized. It also utilizes a shunt current-sensor to monitor and regulate the current through the electrode via feedback, thus enabling flexible and safe stimulation. Since there are no explicit current sources or current limiters, wasteful energy dissipation across such elements is naturally avoided. The dynamic power supply allows efficient transfer of energy both to and from the electrode and is based on a DC-DC converter topology that we use in a bidirectional fashion in forward-buck or reverse-boost modes. In an exemplary electrode implementation intended for neural stimulation, we show how the stimulator combines the efficiency of voltage control and the safety and accuracy of current control in a single low-power integrated-circuit built in a standard .35 μm CMOS process. This stimulator achieves a 2x-3x reduction in energy consumption as compared to a conventional current-source-based stimulator operating from a fixed power supply. We perform a theoretical analysis of the energy efficiency that is in accord with experimental measurements. This theoretical analysis reveals that further improvements in energy efficiency may be achievable with better implementations in the future. Our electrode stimulator could be widely useful for neural, cardiac, retinal, cochlear, muscular and other biomedical implants where low power operation is important.
在本文中，我们提出了一种新颖的节能电极刺激器。我们的刺激器使用感应存储和动态电源中的能量回收。这种电源以绝热方式驱动电极，从而最大限度地减少能量消耗。它还利用分流电流传感器通过反馈来监测和调节通过电极的电流，从而实现灵活和安全的刺激。由于没有显式的电流源或电流限制器，因此自然避免了这些元件中浪费的能量耗散。动态电源允许高效地在电极之间进行能量传输，并基于我们在正向降压或反向升压模式下以双向方式使用的 DC-DC 转换器拓扑结构。在用于神经刺激的典型电极实现中，我们展示了刺激器如何在单个低功耗集成电路中结合电压控制的效率和电流控制的安全性和准确性，该集成电路采用标准的.35 μm CMOS 工艺制造。与从固定电源运行的传统电流源基刺激器相比，这种刺激器的能耗降低了 2x-3x。我们对能量效率进行了理论分析，该分析与实验测量结果相符。该理论分析表明，随着未来更好的实现方式，可能会进一步提高能量效率。我们的电极刺激器可能广泛用于神经、心脏、视网膜、耳蜗、肌肉和其他生物医学植入物，因为低功耗操作非常重要。
