Active Books: The Design of an Implantable Stimulator That Minimizes Cable Count Using Integrated Circuits Very Close to Electrodes

作者：Liu Xiao^*; Demosthenous Andreas; Vanhoestenberghe Anne; Jiang Dai; Donaldson Nick

来源：IEEE Transactions on Biomedical Circuits and Systems, 2012, 6(3): 216-227.

DOI：10.1109/TBCAS.2011.2174360

• Active Book
• crosstalk
• distributed stimulation system
• humidity measurement
• implanted device
• integrated circuit
• nerve root stimulator
• passive discharge
• spinal cord injury
• tripole

This paper presents an integrated stimulator that can be embedded in implantable electrode books for interfacing with nerve roots at the cauda equina. The Active Book overcomes the limitation of conventional nerve root stimulators which can only support a small number of stimulating electrodes due to cable count restriction through the dura. Instead, a distributed stimulation system with many tripole electrodes can be configured using several Active Books which are addressed sequentially. The stimulator was fabricated in a 0.6-mu m high-voltage CMOS process and occupies a silicon area of 4.2 x 6.5 mm(2). The circuit was designed to deliver up to 8 mA stimulus current to tripole electrodes from an 18 V power supply. Input pad count is limited to five (two power and three control lines) hence requiring a specific procedure for downloading stimulation commands to the chip and extracting information from it. Supported commands include adjusting the amplitude of stimulus current, varying the current ratio at the two anodes in each channel, and measuring relative humidity inside the chip package. In addition to stimulation mode, the chip supports quiescent mode, dissipating less than 100 nA current from the power supply. The performance of the stimulator chip was verified with bench tests including measurements using tripoles in saline.

• 出版日期2012-6