A low power low niose AFE with continuous time self-calibration filters for ECG monitor and heart beat detection

A low-power low-noise analog front end (AFE) circuit is presented for ECG monitor and QRS feature extraction. For the purpose of low power and small chip area, a 1^st-order high pass filter with tunable pseudo-resistor and small capacitor is proposed, and a low pass G^m-C filter using capacitance scaler technique is adopted. A novel calibration circuit is proposed to calibrate the cut-off frequency of the low-pass filter which is sensitive to PVT. The AFE consumes 10μW and input-referred integrated noise in the signal band is 6μV^rms.