A Programmable Analog Front-End IC Applied for Biomedical Signal Monitoring Systems

In this paper, a programmable low-power analog front-end (AFE) integrated circuit (IC) for biomedical signal monitoring systems is presented. The whole system includes four parts, instrumentation amplifiers (IA), programmable gain amplifiers (PGA), programmable bandwidth filters (PBF) and successive approximation register analog-to-digital convertors (SAR ADC). The proposed IA employs a pseudo-differential structure to enhance the input impedance of the system. A novel hybrid bandwidth extension technology is introduced in the proposed PGA to correct the low-frequency distortion and improve the low-frequency bandwidth. In the design of PBF, the current steering technology is applied to achieve an area-efficient and energy-efficient architecture. Furthermore, a novel efficient switching scheme and a self-calibration dynamic element matching method are presented in the design of SAR ADC to reduce the power consumption and eliminate the effect of capacitor mismatch. In 0.18 mu m CMOS technology, this AFE IC consumes 46.8 mu W and occupies 0.36 mm(2). It achieves a variable gain from 40.4 to 55.1 dB under different modes designed for different biomedical signals. The spurious-free dynamic range and signal-to-noise plus distortion ratio of the proposed SAR ADC are 71.3 and 53.3 dB, respectively, along with a figure of merit of 0.18 pJ/conv.

Automated summary

In this paper, a programmable low-power analog front-end (AFE) integrated circuit (IC) for biomedical signal monitoring systems is proposed. It consists of instrumentation amplifiers (IA), programmable gain amplifiers (PGA), programmable bandwidth filters (PBF), and successive approximation register analog-to-digital convertors (SAR ADC). The design employs various techniques, such as pseudo-differential structure, hybrid bandwidth extension, current steering technology, and self-calibration dynamic element matching, to achieve high performance and low power consumption. The AFE IC consumes only 46.8μW and occupies 0.36mm² in 0.18μm CMOS technology.