No abstract

A multiple-output stimulation ASIC for a peripherallyimplantable neurostimulaiton system was implemented in a 0.18µm CMOS process. The numbers of anodic outputs (NE A ) and cathodic outputs (NE C ) can be set between 1 and 8 with a fixed total output current up to 32.6mA, independent of NE A and NE C . Fast turn on technique was proposed for the stimulator to achieve a settling time of <5.8µs. The ASIC includes a power management unit and an electrode monitoring circuit, which consists of a 10-b ADC for monitoring the high voltage (~15V) stimulator outputs.

The IC designs of an implantable functional electrical stimulation (FES) battery-powered micro-stimulator are presented in this paper. The battery is recharged by receiving power magnetically through a coil under supervision of a power management unit. To limit the heat generation on the stimulator when a large magnetic field is present, an on-chip rectifier is capable of reducing the Q factor of the coil using a time-varying method. The same coil is also used for generating and receiving magnetic fields such that the distances among 16 different stimulator pairs can be estimated simultaneously. The stimulation current is produced from an 8-bit exponential DAC that has a range between ~2.5µA and ~10mA. The stimulator communicates with an external master control unit through a 400MHz wireless link that can support a bit rate of ~2.5MB/s in high speed mode. The total number of stimulators that the communication system can support is 852. IEEE 2008 Custom Intergrated Circuits Conference (CICC)978-1-4244-2018-6/08/$25.00 ©2008 IEEE 13-1-1

The Alfred Mann Foundation is completing development of a coordinated network of BION microstimulator/sensor (hereinafter implant) that has broad stimulating, sensing and communication capabilities. The network consists of a master control unit (MCU) in communication with a group of BION implants. Each implant is powered by a custom lithium-ion rechargeable 10 mW-hr battery. The charging, discharging, safety, stimulating, sensing, and communication circuits are designed to be highly efficient to minimize energy use and maximize battery life and time between charges. The stimulator can be programmed to deliver pulses in any value in the following range: 5 microA to 20 mA in 3.3% constant current steps, 7 micros to 2000 micros in 7 micros pulse width steps, and 1 to 4000 Hz in frequency. The preamp voltage sensor covers the range 10 microV to 1.0 V with bandpass filtering and several forms of data analysis. The implant also contains sensors that can read out pressure, temperature, DC magnetic field, and distance (via a low frequency magnetic field) up to 20 cm between any two BION implants. The MCU contains a microprocessor, user interface, two-way communication system, and a rechargeable battery. The MCU can command and interrogate in excess of 800 BlON implants every 10 ms, i.e., 100 times a second.

No abstract