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yutian
Joined: 22 Sep 2006
Posts: 32
Helped: 2
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 24 Aug 2007 2:45 Level-shift circuit |
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Hi, I want to design a level-shift circuit recently(5v-24v). Who has some paper or article, circuit?
Thanks a lot
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pfd001
Joined: 23 Jul 2005
Posts: 397
Helped: 34
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| 24 Aug 2007 9:03 Level-shift circuit |
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| Is it digital signal or analog signal
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freetofree
Joined: 21 Mar 2007
Posts: 25
Helped: 2
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| 25 Aug 2007 11:16 Re: Level-shift circuit |
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| charge pump?
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venky442
Joined: 28 Jun 2007
Posts: 13
Helped: 2
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| 25 Aug 2007 20:11 Re: Level-shift circuit |
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Hi,
do u want to design a level up or down shift circuits which can be useful in SOC applications with only sinlgle mail power supply.
u can get these papers from IEEE with level shift circuits as the head line in the search box.
these can reduces the no of interconnects and complexity.
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runblade
Joined: 01 May 2002
Posts: 36
Helped: 1
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| 25 Aug 2007 22:05 Re: Level-shift circuit |
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| Hi, Give a look to step-up circuits (buck boost typology) from several semiconductors manufacturer (TI,Linear,Maxim,National,etc.)
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Sadegh.j
Joined: 29 Nov 2006
Posts: 629
Helped: 30
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| 26 Aug 2007 10:23 Re: Level-shift circuit |
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| Are you looking for a simple DC-to-DC Boost converter by any chance?
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liuyonggen_1
Joined: 12 Dec 2005
Posts: 187
Helped: 4
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| 26 Aug 2007 10:32 Re: Level-shift circuit |
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what's application for this kind of level-shift?
In my opinion, in soc design, level-shift is the brige of analog voltage and digital voltage.
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yutian
Joined: 22 Sep 2006
Posts: 32
Helped: 2
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| 27 Aug 2007 3:19 Level-shift circuit |
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Thanks all.
I want to design a level up shift circuits(5V-24V). In the circuit, the rising time and fall time are very short (<40ns).
Anyone have some paper or aiticle?
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ameed
Joined: 28 Jun 2007
Posts: 119
Helped: 5
Location: INDIA
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| 27 Aug 2007 8:40 Re: Level-shift circuit |
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Hi,
do you want to design a level up or down shift circuits which can be useful in SOC
applications with only sinlgle rail power supply.
you can get these papers from IEEE with level shift circuits as the head line in the search box.
there is a EDACAFE.COM in which you can getting papers.
these can reduces the no of interconnects and complexity.
thanx......
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ambreesh
Joined: 21 Feb 2005
Posts: 365
Helped: 21
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| 27 Aug 2007 15:34 Re: Level-shift circuit |
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You want a simple level shifter that would take your signal which is (0,5) to a signal that is (0,24).
I hope my understanding is correct.
Have 2 crosscoupled PMOS connected to the 24V supply.
Have 1 NMOS below each.
The sources of the NMOS are connected to vss.
One of the NMOS is driven by the 5V signal and the other is driven by its inverted signal.
Take care that the devices you use for PMOS can handle 24V on their gates or are 24V compatible.
Also the NMOS have to be same as one of them would see 24V at its drain. Else you would have to use some cascode devices to protect the NMOS.
Make you NMOS stronger than PMOS as PMOS would have stonger drive than NMOS.
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DenisMark
Joined: 16 Sep 2005
Posts: 303
Helped: 61
Location: Russia
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| 28 Aug 2007 10:30 Re: Level-shift circuit |
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In addititional to ambreesh's post i provide u some papers and links to papers about digital levelshifter circuits (aka differential logic):
http://www.edaboard.com/viewtopic.php?p=806653#806653
http://www.edaboard.com/viewtopic.php?p=830858#830858
http://www.edaboard.com/viewtopic.php?p=830853#830853
http://www.edaboard.com/viewtopic.php?p=710330#710330
There are many free avaliable US patents also.
The main rule of thumb the high voltage side cross coupled pair must have lower driving capability than low voltage side MOSFETs for all PVT corners. Keep MOS's sizes small to decrease propagation delays and rise/fall times. Take care with reability of MOSFETs.
Don't forget push "helped me" button if my help is usefull.
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yutian
Joined: 22 Sep 2006
Posts: 32
Helped: 2
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| 29 Aug 2007 4:22 Level-shift circuit |
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thanks all.
Recently i have downed some paper and studyed the principle of level shift.
In our circuit, we care the level-shift rising time, falling time, area, leakage current.
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yutian
Joined: 22 Sep 2006
Posts: 32
Helped: 2
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| 14 Feb 2008 10:32 Level-shift circuit |
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Thabks to all.
I have done the level-shift citcuit and the audio amo and dc-dc converter.
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northeast1
Joined: 21 Jun 2007
Posts: 145
Helped: 4
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| 13 May 2008 9:57 Re: Level-shift circuit |
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| yutian wrote: |
Hi, I want to design a level-shift circuit recently(5v-24v). Who has some paper or article, circuit?
Thanks a lot |
cross couple structure
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shaq
Joined: 23 Jul 2005
Posts: 310
Helped: 9
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| 14 May 2008 2:44 Level-shift circuit |
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If I want to design a level-shift circuit having low input voltage (eg. 0.85v shift to 2.5v), the cross-couple structure can not be used in this situation.
How to design a level-shift circuit to work in low input voltage?
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ljy4468
Joined: 20 Jul 2005
Posts: 140
Helped: 3
Location: South Korea
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| 14 May 2008 3:13 Level-shift circuit |
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| shaq// why that's not possible??
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shaq
Joined: 23 Jul 2005
Posts: 310
Helped: 9
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| 14 May 2008 6:50 Re: Level-shift circuit |
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| ljy4468 wrote: |
| shaq// why that's not possible?? |
Because clk and clkb (inverted signal) is needed in cross-couple-typed level shifter.
0.85v is too small to pass a inverter.
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supreet_95
Joined: 23 Sep 2007
Posts: 49
Helped: 8
Location: bangalore
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| 14 May 2008 16:16 Level-shift circuit |
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can use cross_coupled pmos latch topology placed above two differential nmos structures with (complimented inputs). U can put a series enable switch in series of both path, so that when the input power supply goes away, the floating inputs wont cause high currents in 2nd stage and the series switch can be swithed off.
Hope this helps.
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