Neuromuscular stimulation is widely used for rehabilitation and movement assist devices, due to its safety, efficacy, and ease of operation. For repeatable and accurate muscular contractions, a voltage controlled current sources (VCCS) with high compliance is required. Conventional VCCS design requires high-voltage rated operational amplifiers, which are expensive and consume large power. Moreover, conventional stimulators are not viable for simultaneous stimulation of muscle synergies, as they require multiple VCCS operating at the same time. This invention presents a neuromuscular stimulator with a multistage driver circuit wherein, a VCCS connected to an output driving stage comprising of folded-cascode transistor buffers and a bidirectional current mirror circuit. The multistage driver circuit uses inexpensive low-voltage rated operational amplifiers that consume 95% less power. Additionally, we disclose a stimulation method wherein only a single current source drives several output drivers connected in series or parallel to simultaneously stimulate multiple muscles or muscle synergies.
