A First-Order Derivative-Based QRS-Detection Circuit in Time Domain for ECG Sensors

A novel low-power first-order derivative-based QRS-detection circuit is presented in this brief. The low-power performance is achieved by employing a time-based differentiator circuit instead of the voltage differentiator and also using two D-Flip-Flop (D-FF) blocks for threshold comparing instead of voltage comparators in conventional derivative-based circuits. The proposed circuit is designed and simulated in 180 nm TSMC CMOS process occupying $0.026~mm^{2}$ silicon die area. The simulation results yield a detection error rate of 1.49%, with sensitivity and positive prediction rates of 99.26% and 99.25%, respectively. The power consumption is about 39.8 nW from a 0.8 V supply voltage.