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isaacnewton
Joined: 13 May 2004
Posts: 155
Helped: 2
Location: Earth Village
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 08 Sep 2006 18:25 How to analysis this circuit? |
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How to analysis this circuit? What's the advantage and disvantage of the circuit? Especially, the circled part.
The circuit is copied from Razavi's book. Page 132, Figure 4.39.
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sgupta_one
Joined: 08 Sep 2006
Posts: 15
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| 08 Sep 2006 18:58 Re: How to analysis this circuit? |
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| Refer to book by Milman & Grabel
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isaacnewton
Joined: 13 May 2004
Posts: 155
Helped: 2
Location: Earth Village
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| 08 Sep 2006 19:05 Re: How to analysis this circuit? |
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I don't have this book.
| sgupta_one wrote: |
| Refer to book by Milman & Grabel |
Added after 3 minutes:
Could you just give me a hint? Thanks.
| sgupta_one wrote: |
| Refer to book by Milman & Grabel |
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pixel
Joined: 16 Sep 2004
Posts: 569
Helped: 59
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| 08 Sep 2006 20:21 Re: How to analysis this circuit? |
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I would say latch...
small circuit ressistance of this block is -2/gmp.
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aland
Joined: 09 Sep 2006
Posts: 15
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| 09 Sep 2006 3:09 Re: How to analysis this circuit? |
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| Differential Driver with current control( or Enable), Vout will toggle polarity.
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windgone0204
Joined: 08 Sep 2006
Posts: 13
Helped: 1
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| 09 Sep 2006 3:57 How to analysis this circuit? |
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| It is a passive feedback in the comparator circuit which can emprove the speed performance.You can refer it to Allen's book.p471
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shaq
Joined: 23 Jul 2005
Posts: 371
Helped: 39
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| 11 Sep 2006 15:36 How to analysis this circuit? |
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| Just draw a small-signal model, you'll get the negative resistance of them.
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Davood Amerion
Joined: 01 Mar 2005
Posts: 588
Helped: 90
Location: Persia
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| 11 Sep 2006 17:41 How to analysis this circuit? |
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| M1, M2 makes comparator, and M3, M4 make hystersis for this circuit (schmitt trigger).
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hb_cancer
Joined: 25 Jul 2005
Posts: 64
Helped: 6
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| 12 Sep 2006 5:08 Re: How to analysis this circuit? |
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Hi there !
Well if you observe the book, the reasoning is as follows or infact try reasoning them yourself step by step:
1. What is the need for an amplifier ?
2. What is the advantage of having an amplifier in Common Source(CS) Configuration?
3. How can the gain of the CS amplifier be improved or infact varied?
4. If gain can be varied by Rd resistance, then it could be logical to have a very large value of resistance at the drain, so what are the types of load resistances possible?
5. If a Mos Transistor is chosen as load then what are the advantages it provides in order to improve the gain ?
6. What if the gain is acheivable, but the gain is not constant or varies with the supply voltage, so, whats the need for source degenetration?
7. All the above were wrt a single stage amplifier but, what is the advantage of a differential amplifier design?
If you could justify correctly the reasons for the above Questions you will clearly understand the need for the Highlighted transistors.
Hope this is of any Help to you. If there are any further queries post them here...
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isaacnewton
Joined: 13 May 2004
Posts: 155
Helped: 2
Location: Earth Village
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| 13 Sep 2006 1:09 Re: How to analysis this circuit? |
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The up figure - when (Vin1-Vin2) sweeps from -1.5 V to 1.5 V.
The bottom figure - when (Vin1-Vin2) sweeps from 1.5 V to -1.5 V.
| Davood Amerion wrote: |
| M1, M2 makes comparator, and M3, M4 make hystersis for this circuit (schmitt trigger). |
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shake2004
Joined: 22 Feb 2005
Posts: 62
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| 13 Sep 2006 11:14 Re: How to analysis this circuit? |
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| referring to allen's book about the comparator or any digital circuit design book
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walker5678
Joined: 17 May 2006
Posts: 131
Helped: 4
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| 19 Sep 2006 10:00 Re: How to analysis this circuit? |
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| It is the positive feedback which improve speed performance.
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rfic
Joined: 14 Dec 2003
Posts: 293
Helped: 4
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| 20 Sep 2006 4:24 How to analysis this circuit? |
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| You can refer it to David John's book.
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teteamigo
Joined: 05 Mar 2005
Posts: 132
Helped: 14
Location: Portugal
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| 21 Oct 2006 2:55 Re: How to analysis this circuit? |
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Simple:
Vout switchs M3 or M4 to triode.
Comparator.
Last edited by teteamigo on 24 Oct 2006 13:02; edited 1 time in total |
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fanrong
Joined: 20 Oct 2006
Posts: 126
Helped: 1
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| 24 Oct 2006 4:06 Re: How to analysis this circuit? |
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| I would say this is a amp with positive feedback or a comparator with hysterysis .
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beckchm
Joined: 13 Nov 2005
Posts: 210
Helped: 3
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| 29 Nov 2006 16:09 Re: How to analysis this circuit? |
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| resistence is negative , but positive feedback
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fashion
Joined: 01 Sep 2004
Posts: 29
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| 09 Apr 2007 7:44 How to analysis this circuit? |
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| It is a positive feedback, and sometimes use it as latch function.
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rob1012
Joined: 27 Mar 2007
Posts: 17
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| 11 Apr 2007 6:35 Re: How to analysis this circuit? |
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Hello...
i think that is a gate cross connected load used to speed up switching times.. When output at one side falls to a level that triggers one PMOS load on, output on the other side quickly goes VDD or approximately VDD-Vthp..
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