Level shifter

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lokeyh

Joined: 29 Sep 2004
Posts: 216
Helped: 51

28 Oct 2004 9:02 Level shifter

Hi,

I need to design a low-voltage to high-voltage level shifter. Is there any recommended ebooks or papers on the designing of low-voltage to high-voltage level shifter? Any recommendations on the architecture for level shifter?

Thanks in advance.

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Colbhaidh

Joined: 10 Aug 2004
Posts: 232
Helped: 35
Location: Scotland

28 Oct 2004 9:41 Re: Level shifter

What voltages are required ?
See attached jpeg for 1.8V to 5V up convertor

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yeewong_su

Joined: 12 Oct 2004
Posts: 126
Helped: 3

29 Oct 2004 7:52 Level shifter

Use above CKT. please pay attention the positve feedback and latch the voltage

djalli

Joined: 10 Nov 2001
Posts: 887
Helped: 15
Location: 1600 Pennsylvania Avenue, Washington DC 20500

29 Oct 2004 7:57 Re: Level shifter

lokeyh wrote:

Hi,
designing of low-voltage to high-voltage level shifter? Any recommendations on the architecture for level shifter?

How much high-voltage level shifter we are talking about? If it is in ranges of 5-100volts use a power opamp and if more I suggest you to use a transformer.

piao

Joined: 12 Feb 2003
Posts: 223
Helped: 7

31 Oct 2004 13:52 Level shifter

Hi, yeewong_su,

Can you provide more in detail about those stuffs?

Thanks in advance

lokeyh

Joined: 29 Sep 2004
Posts: 216
Helped: 51

01 Nov 2004 2:32 Re: Level shifter

I am asking in terms of IC design. The problem with the circuit provided by yeewong_su is that it depends on how low the 1.8V can go. if the 1.8V goes down to 0.8V, the thick-oxide NMOS at the 2.5V portion will not be able to pull the signal low. Is there any other circuits?

Colbhaidh

Joined: 10 Aug 2004
Posts: 232
Helped: 35
Location: Scotland

01 Nov 2004 15:12 Re: Level shifter

Try this one (TK =thick gate )

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lokeyh

Joined: 29 Sep 2004
Posts: 216
Helped: 51

02 Nov 2004 2:46 Re: Level shifter

Hi Colbhaidh,

I will try the design.

Hi all,

Are there other architectures for level-shifter?

kkoko

Joined: 07 Dec 2004
Posts: 22

05 Jan 2005 20:32 Re: Level shifter

If your siganl come from NMOS transitor you can use PMOS common drain circuit to obtain high voltage level shift

Teddy

Joined: 15 Sep 2004
Posts: 328
Helped: 42

05 Jan 2005 22:00 Re: Level shifter

how about to mirror current? Use NMOS for mirroring. It works but I can't show the structure.....

dreamheater

Joined: 03 Jan 2005
Posts: 11

06 Jan 2005 4:04 Re: Level shifter

This also depends on how fast the signal goes, and how much load needs to be driven. I assume the input is a digital signal while the output is to control analog circuitry. The cross coupled structure can work up to MHz range. If higher speed is needed, may need to cascade a few inverters.

kawaiicat

Joined: 23 Dec 2004
Posts: 30
Helped: 1

06 Jan 2005 5:11 Re: Level shifter

any reference books talk about?
i want to learn how to design also
= p

chihyang wang

Joined: 21 Dec 2004
Posts: 8

07 Jan 2005 1:44 Level shifter

It is quite interesting to read the low-voltage to high voltage level shifter . But I meet a problem. I need to design a 1Gbps to several Gbps PECL output buffer, the traditional source follower's efficiency is too low . Is there any good alternative choice?

alanbrooke

Joined: 13 Feb 2004
Posts: 40

07 Jan 2005 9:32 Re: Level shifter

What is the speed of your level shifter?
For the frequency under 300MHz for 0.18um CMOS process, you could use the simple circuit with 2 PMOS latch and 2 NMOS .