| Summary: | 碩士 === 國立交通大學 === 電機工程學系 === 106 === Parkinson patients, receiving L-DOPA drug treatment, can really get the symptoms improved; however, after several years of treatment, most of them will face a "switch phenomenon" with poor efficacy. At this point, the "Deep Brain Stimulation (DBS)", which has undergone surgery, has become another treatment option.
The subject of this paper is to propose a fully differential preamplifier circuit for the Parkinson's disease treatment system (deep brain stimulation) to amplify the local field potential signal and filter out the components of the non-Parkinson's disease-related frequency band. In the sub-circuit design, to eliminate non-ideal components, such as flicker noise, thermal noise, etc, improve its signal to noise ratio, and increase the local field potential signal resolution, the circuit uses a two-stage fully differential inverter-based CMOS amplifier. And by designing the transistor sizes, the two-stage fully differential inverter-based CMOS amplifier can suppress noise. The transistors of the input stage operating in the weak inversion region can reduce the flicker noise and the power consumption. In addition, if the resistor in the low-pass filter has also used the virtual resistance, the output signal will lead to distortion of the phenomenon. So this resistor is replaced by switched-capacitor resistor to avoid signal distortion. The system gain is designed to be adjustable among 50dB, 60dB, and 70dB magnification that can avoid the distortion of output signal due to saturation of the amplifier. Pseudo-resistors are used with the large resistance required to produce very low frequency poles. PMOS is used to implement the pseudo-resistor, because the flicker noise of the PMOS is smaller at the low frequency. The overall circuit has the performance of high resolution, low power consumption, and low noise to achieve the specification of a health electronic system.
The bandwidth of the overall preamplifier circuit is designed to be from 1Hz to 100Hz. When the input signal is 30Hz, 1mVp, the system gain is 50dB and the total harmonic distortion (THD) is -74.9dB. This circuit was fabricated by TSMC 0.18μm standard CMOS 1P6M process. At 1.8V power supply, the total power consumption is about 35μW and the input-referred-noise is 0.93μVrms.
|
|---|
