Reconfigurable Noise Shaping Successive Approximation Register Analog-to-digital Convertor For Biomedical Signal Processing

With the development of information and communication technology,medical services are also developing remotely and platform-based.For doctors,biomedical signal is the only way to observe patients remotely,then there is the high requirements to design biomedical signal acquisition system.As the core of the biomedical signal acquisition system,the use of high-precision ADC can reduce the performance demand on the analog front end and achieve higher energy efficiency.With benefits of high resolution,easy implementation and low power-consumption,the noise-shaping SAR ADC was combined of the advantages of SAR ADC and ?-? ADC,which fits biomedical signal collection.Due to gain error and phase error of passive switched-capacitor integrator,the noise-shaping ability of passive noise-shaping SAR ADC is poor.Based on passive noise-shaping method,a low gain OTA and positive feedback circuit was designed.The gain error and phase error were attenuated by the designed activepassive noise-shaping module,and only a little power consumption was increased.Based on 180 nm process,with signal bandwidth 10 KHz,sampling rate 320 KHz,power-consumption 109 ?W,the active passive hybrid noise-shaping SAR ADC has the ENOB of 15.6 bits,Fo M of 175.1 d B.And the ENOB surpasses 15 bits between temperature-40 to 85 degrees at different process corner.Also,the ADC is designed for reconfiguration.at high-performance mode,noise-shaping module is turned on,and SAR ADC is configured into 8 bits;at low-power mode,SAR ADC is reconfigured into 8 bits,and sampling rate is decreased into 20 KHz.With the power-consuming 0.24 ?W,the ADC has the ENOB of 7.8bits,Fo M of 151.4 d B at 27 degree under tt process.And the ENOB surpasses 7.5 bits between temperature-40 to 85 degrees at different process corner.