A Signal-Specific Integrating Analog-to-Digital Converter for Biomedical Applications

This work describes a modified architecture for integrating analog-to-digital converters (ADC) for use in biomedical or any other applications where the input signal has small and slow variations. In this architecture, instead of digitizing every new analog sample independently, the difference of the new sample with the previous sample is converted to digital. With this idea, we can therefore considerably reduce the power consumption of the integrating ADC. In this paper, design considerations and simulation results of an 8-bit, 4 kS/s ADC in a 0.18μm CMOS technology are addressed to show the effectiveness of the idea. The proposed ADC is more power efficient when used for input signals that are very slow and have a small variation in voltage amplitude. Simulations confirm that the proposed ADC architecture shows more than 40% power saving compared to conventional architecture for an input signal amplitude of 0.2VFS.