Electrocardiogram (ECG) signal is widely used in the diagnosis of heart diseases. Since the amplitude of this signal is very low, a high-gain low-noise amplifier with a high common mode rejection ratio (CMRR) is needed. In portable applications a battery provides the required power for the ECG device. Hence, ECG amplifiers should have low area and power consumption. In this paper, an instrumentation amplifier for ECG application is proposed in which MOSCAPs are used to reduce the circuit area. MOSCAPs are inherently nonlinear and a technique is presented to reduce the impact of this non-linearity. In ECG systems, a driven right-leg circuit is used to increase the CMRR of the amplifier. In this paper a class AB buffer is employed to implement this circuit. The simulation results show that the gain of the proposed amplifier is 46.18 dB and its input referred noise is 7.8 µV rms over the frequency range of 0.3 Hz to 150 Hz. The total power consumption of the designed amplifier is 72 nW. The amplifier CMRR is 96 dB and its total harmonic distortion (THD) is 0,68% (at 60 Hz).
Considerable area occupied by capacitors is one of the main issues in the design of many ICs, especially in biomedical applications. MIM capacitor can be replaced by the MOSCAP to reduce the chip area and cost. Although the MOSCAP shows a non-linear behavior, linearization can be performed to some extent using serial and parallel compensation. In this paper, a new approach is presented, by which the impact of MOSCAP non-linearity on the THD of the circuit is reduced. The proposed technique is used in an electrocardiogram ampli er. The appropriate structure for each MOSCAP of the ampli er is selected by analyzing the non-linear e ect of the MOSCAPs on the ampli er's output linearity. The non-linear e ect of MOSCAP is reduced by choosing the appropriate slopes in the MOSCAP capacitance-voltage curve. As a result, the occupied area of the ampli er is reduced to less than 10 percent of the area of the ampli er with MIM capacitors, while the THD is not changed considerably. The output THD is 0.65% at 60 Hz and the total power consumption is 72 nW.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.