基于混合模式快速电荷平衡的神经刺激器

A Stimulator with Hybrid Mode Fast Charge Balancing Method

设计实现了一种可用于脊髓神经刺激器的多通道大电流神经刺激器。提出将电极短接和插入短电流脉冲相结合的混合模式,在大电流下,能更加快速地实现电荷平衡。电路设计上,将ADC动态比较器的回踢噪声消除技术应用于神经刺激器,使得动态比较器在输入压差较小时能够输出正确的比较结果,从而将电极上残留电压保持在更安全的范围内。基于CSMC 0.25μm BCD工艺进行设计与仿真,结果表明,在单向且最大刺激电流为4 mA、刺激脉宽为60μs、刺激周期为750μs的条件下,该15 V、16路神经刺激器能实现±50 mV安全电压的有源电荷平衡。

A multi-channel stimulator circuit with large stimulation current was designed and implemented,which could be used in spinal cord stimulation.At system level,two charge balancing approaches,electrode shortening and pulse insertion,were combined to one system to achieve charge balancing in shorter time with a large current.At schematic level,a kickback noise cancelling technique was used to improve the performance of dynamic comparator and to keep the residual voltage on electrodes in a safer region.The circuit was designed and implemented in CSMC 0.25μm BCD process.Results showed that this 16-channel,15-V stimulator was able to keep the residual voltage on the electrodes within±50 mV when a 4 mA monophasic and maximum stimulation current was applied with 60μs stimulation duration and 750μs stimulation period.