Operational amplifiers in electrocardiogram devices

This paper describes a superior performance operational amplifier developed that applied into electrocardiogram (ECG). The performance of the op-amp is improved in several areas: lower power dissipation, reduced amplifier noise, and enhanced signal accuracy. By combining these improvements, this paper can achieve optimal performance for ECG applications. For solving low power dissipation the operational amplifier can use Logarithmic compression which is used in Variable Gain Amplifiers (VGA) and Low Pass Filters (LPF). In addition, HPSDM's Op-Amp Sharing Technology can reduce the power, as well. The following two methods can solve problems that occur at high power consumption. For example, common-mode interference can occur, Right-leg drive circuitry and advanced amplifiers can be used in the circuits. With high power, wide bandwidth, high linearity, and low noise Microwave monolithic integrated circuit (MMIC) amplifiers can be used to reduce all these defects. To remove the amplifier noise, Pseudo-resistors are one method applied to ECG. Also, use a P-channel input device with an N-channel load because it has lower flicker noise. In the operational transconductance amplifier (OTA) circuit, a high-pass filter can be generated which can reduce unnecessary low frequencies. High-pass filters with sharp transition bands of trap filters can suppress the power line noise. In addition, the lock-in amplifier (LIA) is capable of extracting weak signals with great sensitivity.