A High-Voltage Generation Charge-Pump IC Using Input Voltage Modulated Regulation for Neural Implant Devices

Abstract

This brief presents a high-voltage generation charge pump integrated circuit (IC) with a novel regulation scheme for neural stimulation applications. Instead of using a widely used pulse frequency modulation approach with a variable clock frequency for regulation, an input voltage modulated regulation with a low drop-out regulator at the input of the feedforward path is used to maintain the charge pump output voltage with varying load current between <inline-formula> <tex-math notation= LaTeX >$10~{\\mu }\\text{A}$ </tex-math></inline-formula> to 1 mA. The proposed charge pump IC, implemented with 0.18-<inline-formula> <tex-math notation= LaTeX >$\\mu \\text{m}$ </tex-math></inline-formula> standard low-voltage CMOS process, reliably generates 12.8-V output voltage from a 2.8-V input and achieves more than 80% power efficiency at 1 mA load condition. The proposed IC occupies 0.6 mm<inline-formula> <tex-math notation= LaTeX >$^{2}$ </tex-math></inline-formula> of core die area.