An energy-efficient analog circuit for detecting QRS complexes from ECG signal

In this paper, an analog current-mode circuit with low power consumption and low area is designed and implemented to detect the QRS complexes from the ECG signal. An efficient algorithm is proposed for this purpose which uses the energy operator. This algorithm is fully implemented in the analog domain with the transistors operating in the subthreshold region, resulting in ultra-low power consumption. The proposed method is evaluated with the data contained in the standard MIT-BIH arrhythmia database and reaches the acceptable values of 98.53% for the average accuracy, 99.41% for sensitivity and 99.13% for positive prediction. The proposed circuit is implemented in 0.18 mu m CMOS technology with a power supply of 1.8 V. Using this circuit, there is no need to use an analog-to-digital converter in the detector system, which can lead to more reduction in the power consumption and area of the system. With power consumption of 15.77 nW and area of 0.078 mm2, this circuit is suitable for using in wearable and implantable applications.