Hi, glad to know your knowledge shared. Do you have more material on Chopper Amplifier? I would like to ask you for material or more in-depth videos about it, to better understand Chopper Amplifer. Thank you very much
Hi Tú Anh Nguyễn, nice to meet you and I don't have more far. But, could you please suggest what kind of more in-depth Chopper Amplifier you need? I can try to make more accordingly. :)
Thanks for reviewing the chopper design. This is the first time hearing double chopping. I always found the most difficult part in switch capacitor circuit design is suppress the charge injection noise.
Hi Bobby, Thank you so much for the feedback. You're correct that suppressing the charge injection noise is a similar challenge in switch capacitor circuit while the switching frequency is high. So, that's why to double chopping and mitigate w/ a lower switching frequency here. 🙂
Hi CC, nice video as always. For the switches charge injection, i think it is mainly the switch mismatch that causes mismatched charge injection from main path and cross coupled path, that gets rectified eventually to create a residual dc offset. If switches are matched, then the waveform at Vx node will have same net charge injected at both rising and falling (as one switch turns off and other turns on) leading to twice frequency impulse like waveform at Vx node. This waveform when passed through amplifier and demodulated will lead to 0 offset.
Hi Abhirup,Thank you so much for your feedback. You're correct. The switch mismatch (including the parasitic mismatch) will be the main reason, but we cannot calibrate the mismatch of the switches, which are used to calibrate the amplifier's mismatch; therefore, the only way we could do is to accept the mismatch of the switches and mitigate with a few images shown here. Hopefully, this helps everyone in the future.
@@circuitimageI would like to share some of your videos on Facebook, is that ok for you? Just let my friends know that there is a great circuit design channel on TH-cam.
Nice video for tips for designing a better chopper op-amp Two Question: How to choose chopper frequency fchop? We know fchop should be larger than the 1/f corner frequency to remove the flicker noise. But compared with op-amp Gain-Bandwith (GBW). Some people said fchop < fGBW, while others claimed fchop > fGBW. What's your thoughts? Thank you! Also Can you please explain more about the low-pass filter part? I see people use Switced-Capacitor norch filter to filter the fchop, which I guess is more efficient
Hi Yushi, Nice to meet you and thank you so much for the good questions. I have comments below w/ [CC]. 😊 One question: How to choose chopper frequency fchop? We know fchop should be larger than the 1/f corner frequency to remove the flicker noise.But compared with op-amp Gain-Bandwith (GBW). Some people said fchop < fGBW, while others claimed fchop > fGBW. What's your thoughts? [CC] fchop > fGBW may cause lots of charge injection, which may not be practical to chop effectively if the fGBW is too high; therefore, that depends on the value of the fGBW and the process characteristics.Also Can you please explain more about the low-pass filter part? I see people use Switced-Capacitor norch filter to filter the fchop, which I guess is more efficient[CC] Sure. Since the Switced-Capacitor notch filter (SCNF) can provide a very high precise notch frequency; therefore, I agree with you that the SCNF is more efficient.
Hi, glad to know your knowledge shared. Do you have more material on Chopper Amplifier? I would like to ask you for material or more in-depth videos about it, to better understand Chopper Amplifer. Thank you very much
Hi Tú Anh Nguyễn, nice to meet you and I don't have more far. But, could you please suggest what kind of more in-depth Chopper Amplifier you need? I can try to make more accordingly. :)
Thanks for reviewing the chopper design. This is the first time hearing double chopping. I always found the most difficult part in switch capacitor circuit design is suppress the charge injection noise.
Hi Bobby, Thank you so much for the feedback. You're correct that suppressing the charge injection noise is a similar challenge in switch capacitor circuit while the switching frequency is high. So, that's why to double chopping and mitigate w/ a lower switching frequency here. 🙂
Hi CC, nice video as always. For the switches charge injection, i think it is mainly the switch mismatch that causes mismatched charge injection from main path and cross coupled path, that gets rectified eventually to create a residual dc offset. If switches are matched, then the waveform at Vx node will have same net charge injected at both rising and falling (as one switch turns off and other turns on) leading to twice frequency impulse like waveform at Vx node. This waveform when passed through amplifier and demodulated will lead to 0 offset.
Hi Abhirup,Thank you so much for your feedback. You're correct. The switch mismatch (including the parasitic mismatch) will be the main reason, but we cannot calibrate the mismatch of the switches, which are used to calibrate the amplifier's mismatch; therefore, the only way we could do is to accept the mismatch of the switches and mitigate with a few images shown here. Hopefully, this helps everyone in the future.
@@circuitimage I agree CC with your input. I knew about this nested chopper technique before but never used it ever still. Thanks for sharing.
@@abhiruplahiri1 Sure. Any time.
Thank you for making this video, it really helps me a lot!
Could I share your video on social media?
Hi Hung, thank you for the feedback. I'm glad that helps. What's social media you're referring to?😃
@@circuitimageI would like to share some of your videos on Facebook, is that ok for you?
Just let my friends know that there is a great circuit design channel on TH-cam.
@@hungshawn2530 Yes, that's good to me if that really helps your friend. I would be very happy as well. 😄
Nice video for tips for designing a better chopper op-amp
Two Question: How to choose chopper frequency fchop? We know fchop should be larger than the 1/f corner frequency to remove the flicker noise.
But compared with op-amp Gain-Bandwith (GBW). Some people said fchop < fGBW, while others claimed fchop > fGBW. What's your thoughts? Thank you!
Also Can you please explain more about the low-pass filter part? I see people use Switced-Capacitor norch filter to filter the fchop, which I guess is more efficient
Hi Yushi,
Nice to meet you and thank you so much for the good questions. I have comments below w/ [CC]. 😊
One question: How to choose chopper frequency fchop? We know fchop should be larger than the 1/f corner frequency to remove the flicker noise.But compared with op-amp Gain-Bandwith (GBW). Some people said fchop < fGBW, while others claimed fchop > fGBW. What's your thoughts? [CC] fchop > fGBW may cause lots of charge injection, which may not be practical to chop effectively if the fGBW is too high; therefore, that depends on the value of the fGBW and the process characteristics.Also Can you please explain more about the low-pass filter part? I see people use Switced-Capacitor norch filter to filter the fchop, which I guess is more efficient[CC] Sure. Since the Switced-Capacitor notch filter (SCNF) can provide a very high precise notch frequency; therefore, I agree with you that the SCNF is more efficient.