| Summary: | 碩士 === 國立中正大學 === 電機工程研究所 === 100 === In this thesis, a low power OTA-C lowpass filter for ECG detection was implemented. In order to approach the maximally flat in passband, the Butterworth topology was chosen in the filter system. For ECG detected application, the cutoff frequency of lowpass filter was design at 250Hz.
Two kinds of transconductance amplifier are improved from previous work[5], the first one is to change the drain voltage of input transistors and propose an Active Load OTA; the second one is to use the current of current division tech. as another output pair and keep the characteristic of current division tech simultaneously. And re-assign the current of input transistor, we can get two output pairs which have the same transconductance value. We can reduce the number of OTA of 5th lowpass filter system from 11 to 6.
The chip of MODI OTA-C filter used TSMC 0.18μm Mixed Signal 1P6M CMOS process and its area was 0.136mm2. According to the measured results under 1V supply voltage, the total power consumption was 335nW, THD was about -32dB for 200mVpp input. And the bandwidth was below 250Hz can be adopted to eliminate the out-of-band interference of the ECG signal.
|
|---|
