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

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 10 μA to 1 mA. The proposed charge pump IC, implemented with 0.18-μm 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
²
of core die area.