A microstimulator with parameter adjustment for bladder dysfunction

A bladder neuromodulation with a system controller and microstimulator is proposed. The system controller is used for transmitting the stimulating parameters with four functions: fetching, decoding, calculating, and outputting. The fetching circuit receives series parameters from a phase-shift keying demodulator. The decoding circuit decodes the data for the stimulus parameter. The calculating circuit is used to count the timing, which has the timing information of the stimulation for monophasic, charge-balanced biphasic, charge-imbalanced biphasic, and charge-balanced biphasic with delay. The outputting circuit is a finite state machine with four states: anode pulse width, pulse delay width, cathode pulse width, and burst period width. The microstimulator consists of a digital-to-analog converter (DAC) and a stimulus generator circuit. The DAC is a commercial current-mode 8-bit chip. The stimulus generator circuit is realized in a field-programmable gate array to provide the required stimulation current for tissue. The controller is implemented by the TSMC 0.18 μm 1P6M CMOS process. The whole area of the chip is 1.44 mm2 and has a power consumption of 29.7 mW at 1.8 V supply. An animal study is conducted to demonstrate the circuit function and to verify the effect of micturition according to current stimulation.