Oct 30, 2007 #1 M mpig09 Full Member level 4 Joined Aug 26, 2005 Messages 232 Helped 8 Reputation 16 Reaction score 2 Trophy points 1,298 Location Taipei Activity points 2,810 Dear all : The attached file has two sample and hold circuit, I try to analyze the Vout / Vin, but the result always Vout / Vin =1. Could you help me how to analyze the circuit ?
Dear all : The attached file has two sample and hold circuit, I try to analyze the Vout / Vin, but the result always Vout / Vin =1. Could you help me how to analyze the circuit ?
Oct 30, 2007 #2 M MikeR Member level 4 Joined Dec 16, 2006 Messages 75 Helped 9 Reputation 18 Reaction score 3 Trophy points 1,288 Location Belarus Activity points 1,644 What parameter you want analysis? And what model of opamp you use? For begining you can add input votage offset and changing sampling frequency. And what about pedestal error?
What parameter you want analysis? And what model of opamp you use? For begining you can add input votage offset and changing sampling frequency. And what about pedestal error?
Oct 30, 2007 #3 hr_rezaee Advanced Member level 3 Joined Oct 6, 2004 Messages 747 Helped 109 Reputation 218 Reaction score 24 Trophy points 1,298 Location Iran-Mashhad Activity points 4,025 Hi edited see below regards
Oct 31, 2007 #4 M mpig09 Full Member level 4 Joined Aug 26, 2005 Messages 232 Helped 8 Reputation 16 Reaction score 2 Trophy points 1,298 Location Taipei Activity points 2,810 Dear all : First circuit : C0=C5=1.2p C1=C3=0.8p Second circuit : C1=C2=1.2p C0=C3=0.8p Could anyone describe how to analyze ? (analyze principle / formula) Thanks for your kindly help. mpig
Dear all : First circuit : C0=C5=1.2p C1=C3=0.8p Second circuit : C1=C2=1.2p C0=C3=0.8p Could anyone describe how to analyze ? (analyze principle / formula) Thanks for your kindly help. mpig
Oct 31, 2007 #5 hr_rezaee Advanced Member level 3 Joined Oct 6, 2004 Messages 747 Helped 109 Reputation 218 Reaction score 24 Trophy points 1,298 Location Iran-Mashhad Activity points 4,025 Hi sorry I took a mistake. draw half model of fully diff S/H. charges in sampleing phase: Q0=Vcm.C0 Q1=Vin.C1 charges in holding phase: Qout=Q0+Q1=Vcm.C0+Vin.C1 Vout = (Vcm.C0+Vin.C1)/C0 = C1.Vin/C0+Vcm VOdiff=C1.VINdiff/C0 C1=1.2p, C0=0.8p VOdiff=1.5 VINdiff regards
Hi sorry I took a mistake. draw half model of fully diff S/H. charges in sampleing phase: Q0=Vcm.C0 Q1=Vin.C1 charges in holding phase: Qout=Q0+Q1=Vcm.C0+Vin.C1 Vout = (Vcm.C0+Vin.C1)/C0 = C1.Vin/C0+Vcm VOdiff=C1.VINdiff/C0 C1=1.2p, C0=0.8p VOdiff=1.5 VINdiff regards
Oct 31, 2007 #6 M mpig09 Full Member level 4 Joined Aug 26, 2005 Messages 232 Helped 8 Reputation 16 Reaction score 2 Trophy points 1,298 Location Taipei Activity points 2,810 Dear hr_rezaee : For second circuit : Sample phase Q0=Vin*C0, Q1=DAC*C1 Hold phase Vout=Vin + Qout / C0 Qout=Q0+Q1 so, Vout=Vin+ (Vin*C0+DAC*C1) / C0 =Vin + Vin + DAC*(C1/C0) =2*Vin + DAC*(C1/C0) Is it right ? mpig Added after 1 hours 48 minutes: Dear hr_rezaee : Do we need to care +/- sign of capacitor charge in the first and second circuit ? mpig
Dear hr_rezaee : For second circuit : Sample phase Q0=Vin*C0, Q1=DAC*C1 Hold phase Vout=Vin + Qout / C0 Qout=Q0+Q1 so, Vout=Vin+ (Vin*C0+DAC*C1) / C0 =Vin + Vin + DAC*(C1/C0) =2*Vin + DAC*(C1/C0) Is it right ? mpig Added after 1 hours 48 minutes: Dear hr_rezaee : Do we need to care +/- sign of capacitor charge in the first and second circuit ? mpig
Oct 31, 2007 #7 hr_rezaee Advanced Member level 3 Joined Oct 6, 2004 Messages 747 Helped 109 Reputation 218 Reaction score 24 Trophy points 1,298 Location Iran-Mashhad Activity points 4,025 Hi I think there is a mistake in second S/H. I think path from input to output is extra. If we remove this path we have: Sample phase : Q0=Vin.C0, Q1=DAC.C1 Vout=Q0/C0=Vin I'm not shure this circuit is true. regards
Hi I think there is a mistake in second S/H. I think path from input to output is extra. If we remove this path we have: Sample phase : Q0=Vin.C0, Q1=DAC.C1 Vout=Q0/C0=Vin I'm not shure this circuit is true. regards
Nov 1, 2007 #8 M mpig09 Full Member level 4 Joined Aug 26, 2005 Messages 232 Helped 8 Reputation 16 Reaction score 2 Trophy points 1,298 Location Taipei Activity points 2,810 Dear hr_rezaee : I use hspice to verify the gain result, Vout approaches 2*Vin - DAC*(C1/C0) , I try to calculate this result, but the result is still not correct. Could you have any suggest ? mpig
Dear hr_rezaee : I use hspice to verify the gain result, Vout approaches 2*Vin - DAC*(C1/C0) , I try to calculate this result, but the result is still not correct. Could you have any suggest ? mpig
Nov 1, 2007 #9 hr_rezaee Advanced Member level 3 Joined Oct 6, 2004 Messages 747 Helped 109 Reputation 218 Reaction score 24 Trophy points 1,298 Location Iran-Mashhad Activity points 4,025 Hi could you attach an image that shows full circuit? all switches and nodes. regards
Nov 2, 2007 #10 M mpig09 Full Member level 4 Joined Aug 26, 2005 Messages 232 Helped 8 Reputation 16 Reaction score 2 Trophy points 1,298 Location Taipei Activity points 2,810 Dear hr_rezaee : I can't show detail schematic. I hope it is enough to help. mpig
Nov 2, 2007 #11 hr_rezaee Advanced Member level 3 Joined Oct 6, 2004 Messages 747 Helped 109 Reputation 218 Reaction score 24 Trophy points 1,298 Location Iran-Mashhad Activity points 4,025 Hi Sorry I can't Understand. If you can, draw better schematic Please explain where you see this S/H? regards
Hi Sorry I can't Understand. If you can, draw better schematic Please explain where you see this S/H? regards
Nov 2, 2007 #12 M mpig09 Full Member level 4 Joined Aug 26, 2005 Messages 232 Helped 8 Reputation 16 Reaction score 2 Trophy points 1,298 Location Taipei Activity points 2,810 Dear hr_rezaee : It is my project. mpig
Nov 2, 2007 #13 hr_rezaee Advanced Member level 3 Joined Oct 6, 2004 Messages 747 Helped 109 Reputation 218 Reaction score 24 Trophy points 1,298 Location Iran-Mashhad Activity points 4,025 Hi Ok, but you must have more detail about it. such as type of S/H or references. regards