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Message started by Benjamin on Nov 11th, 2008, 9:41pm

Title: what's best type of regulator to get fastest response with low supply?
Post by Benjamin on Nov 11th, 2008, 9:41pm
I am wanting to find the fastest response regulator for a low supply level. Specifically I would like as fast as possible response with w.c. supply of 1.35V, when the output voltage is target at 1.3V.

So what's the fastest option for such small headroom.
If necessary perhaps I could take the current efficiency hit and use a pumped voltage for the diffAmp supply voltage, but not the output driver.

Any suggestion appreciated?
Thanks, Benjamin

Title: Re: what's best type of regulator to get fastest response with low supply?
Post by Berti on Nov 12th, 2008, 1:00am
I don't really see the purpose of having a regulator with only 50mV drop. However, I think that this might be difficult to realize with a traditional LDO circuit.

Regards

Title: Re: what's best type of regulator to get fastest response with low supply?
Post by raja.cedt on Nov 12th, 2008, 1:08am
hi,
   whats your load current in transients?i think for any load its impossible with the existing topologies,if you try to realize with current  topologies,may be u  can do in fast corner,across all corners its very difficult. By the way where u want this much tight spec regulator?
Regards,
rajasekhar

Title: Re: what's best type of regulator to get fastest response with low supply?
Post by vivkr on Nov 12th, 2008, 4:58am

Benjamin wrote on Nov 11th, 2008, 9:41pm:
I am wanting to find the fastest response regulator for a low supply level. Specifically I would like as fast as possible response with w.c. supply of 1.35V, when the output voltage is target at 1.3V.

So what's the fastest option for such small headroom.
If necessary perhaps I could take the current efficiency hit and use a pumped voltage for the diffAmp supply voltage, but not the output driver.

Any suggestion appreciated?
Thanks, Benjamin


Hi,

You can use the textbook LDO scheme. Everything runs on low voltage supplies, and you pump the gate of the output driver which is an NMOS. This has very fast response since it acts like a source follower. Obviously, it is better if you have a triple-well technology that you can tie source-bulk of this NMOS.

The 50 mV drop might be a bit of an issue, especially if you also need high-temperature operation. But give it a try.

I guess you are using an LDO to tame a widely varying supply.

Regards,
Vivek

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