J. Mouine

Computerized transcutaneous control of a multichannel implantable urinary prosthesis

A personal computer interface of a multichannel implantable urinary prosthesis is described. This system is composed of two main parts: the first one is internal and consists of an implant using a 4- mu m CMOS gate array chip controlling a wide variety of waveforms via eight monopolar channels; the second is an external controller featuring a versatile software, a PCB card plugged in a portable microcomputer, and a radiofrequency-coupled technique. This device is used to transmit the power, the data, and the synchronization clock to the implant by a simple binary signal modulating a 20-MHz carrier. The features of implant encapsulation and electrode design and fabrication are also reported.<<ETX>>

A completely programmable and very flexible implantable pain controller

An advanced full programmable pain controller is described in this paper. The system is composed of three main parts: two different external control units and a surgically implanted module. The first external part of the system is intended for the physician and consists of a PC computer system with appropriate application software and hardware interface. It allows programming the internal part through a user-friendly graphical interface. The second external part is for the patient and consists of a simple switch to start and stop stimulation at his convenience. An RF carrier provides both data and power for the implant circuitry through a closely coupled inductive link. The internal part consists of a microstimulator built around a full custom mixed-signal microprocessor generating different programmable current waveforms by executing a set of micro-commands. This chip is mounted together with different satellite components on a hermetically housed hybrid circuit.

Design and implementation of a multichannel urinary incontinence prosthesis

A fully programmable, cell powered urinary incontinence prosthesis is presented. The system is composed of three main parts: two different external control units and a surgically implanted module. Communication between external and internal parts is made through a bidirectional inductive link. The implanted module is built around a full custom mixed-signal ASIC that generates different programmable current waveforms. This chip is mounted together with different satellite components on a hybrid circuit and housed together with a lithium cell in a hermetically sealed titanium case. The first external part of the system is intended for the physician and consists of a PC computer system with appropriate application software and hardware interface. It allows programming the internal part and verifying the system by reading out the main memory content and checking the lithium cell voltage level. The second external unit is to be used by the patient and consists of a simple switch allowing him to stop or to resume stimulation.

A miniaturized implantable spinal cord microstimulator for treating intractable chronic pain

An advanced fully programmable spinal cord stimulation system is described. The system delivers controlled electrical pulses to an electrode array placed on selected nerve fibers along the spinal cord. It is composed of three main parts: two different external control units and a surgically implanted module. The first external part consists of a computer system with completely graphical software and appropriate hardware interface, intended for the physician to program the internal part. The second external unit is a very small simple switch that will be used by the patient to start and stop stimulation at his convenience. A RF carrier provides both data and power for the implant through a closely coupled inductive link. The internal part consists of a microstimulator built around a full custom mixed-signal microprocessor generating different programmable current waveforms. This chip is mounted together with different satellite components on a hermetically housed hybrid circuit.

A new single chip automatic gain control for hearing aids

A new automatic gain control (AGC) is described in this paper. It has a low power consumption, since it is designed in CMOS technology, and an easy external setup using reference voltage inputs. The circuit is built around an operational amplifier using MOS resistive circuits (MRC). This AGC has shown a good linearity and a very weak total harmonic distortion. Some results are included in this paper.

A new prosthetic device for full bladder control

The design and testing of a versatile, implantable eight-channel urinary prothesis developed to restore a normal bladder function for patients with spinal-cord injuries are described. The main application of the device is the stimulation of particular nerves in the sacral roots. The intensity, the format and the timing of the current pulses available at the channel outputs are easily programmable. Those parameters are received transdermally by the implanted device in 13-bit blocks. The information is either loaded into internal registers for immediate processing or stored in an external implantable memory for a deferred processing. A miniaturized (4.51 mm*4.51 mm) implant has been implemented in 3- mu m CMOS full-custom technology, using a total of 12753 transistors. Tests have confirmed the functionality of the chip.<<ETX>>

Resistless electron beam lithography process for the fabrication of sub-50 nm silicide structures

We report on a study of the fabrication of submicron silicide structures with a resistless lithography technique. Several different metals can be used as a basis for producing silicide using this method; in this work, results will be discussed for both platinum and nickel silicide. The feasibility of producing nanostructures using polycrystalline silicon as a base growth layer for metal–oxide–semiconductor, and other device applications have also been demonstrated. Threshold doses for this method for submicron lines (<50 nm) and square areas were obtained in order to establish a framework for the fabrication of more complex devices. Preliminary electrical measurements were carried out which indicate that the resistivity of the silicide is 45 μΩ cm, and that the barrier height of the silicide/(high resistivity silicon) interface is 0.56 eV.

A novel way to generate pseudo-random sequences longer than maximal length sequences

We show that it is possible to generate, using an l-stage shift register, a pseudo-random binary sequence longer than (2/sup l/-1), that is longer than the so-called maximal length sequence. This can be done by subdividing the l-stage shift register into two parts and clocking each part at different speeds. An example is presented to show some results.

A dedicated microprocessor for externally powered implantable pain controller

A 8-channel dedicated microprocessor for externally powered implantable pain control stimulator is presented. It is designed with 8 channels to deliver the stimuli: any subset out of 8 channels can be started or stopped simultaneously. Arbitrary current waveforms can be generated through appropriate programming which can be achieved by an algorithm serially transmitted transdermally. The microprocessor can be configured as biphasic or monophasic or mix operation mode. Particularly, the charge balanced biphasic pulses are easily generated. The design is accomplished with Verilog HDL language description at RTL level. The resulting schematic or netlist is then automatically placed and routed by Preview Cell Ensemble with the 1.5 micron Mitel process.

A new multichannel bladder stimulator

An integrated circuit intended for neural stimulation applications is described. The device has been designed and implemented in CMOS 3- mu m technology. The major advantages of the chip are its programmability and versatility. The intensity, format, and timing of the current pulses available at the eight channel outputs are serially and fully programmable. The different components of the device are controlled by a finite-state machine implemented by a PLA (programmable logic array). This implant can be placed inside the human body for long-term neural stimulation, and it can be used for many neurologic stimulation applications with minor modification of the implant.<<ETX>>