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Design >> Analog Design >> Charge Pump Design
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Message started by Steve_S on Jun 23^rd, 2010, 6:26pm

Title: Charge Pump Design
Post by Steve_S on Jun 23^rd, 2010, 6:26pm

Hi everyone,

I need to develop a CMOS circuit to take a 4 volt DC level and pump it up to 12v on a 10nF capacitor.
I've been looking at dickson charge pumps and it seems there is a significant amount of loss in the basic
design. Can anyone recommend an improvedd architecture which has less loss?

Thanks,
Steve

Title: Re: Charge Pump Design
Post by vivkr on Jun 25^th, 2010, 12:04am

When you say Dickson pump, are you referring to the classic version using diodes? If so, then you may consider using switches instead as these provide a more efficient design. Look up any text on switched-capacitor based chargepumps, e.g. the text from Peng and Samadar.

All this holds only as long as you are not trying to deliver any appreciable amount of power to the load. As soon as you need power, the poor efficiency of switched-cap chargepumps will kill you, and it will be necessary to move to inductor-based DC-DC converters.

Vivek

Title: Re: Charge Pump Design
Post by Steve_S on Jun 27^th, 2010, 5:58pm

Hi Vivek,

Thanks for your response.
Yes, the design we presently have is using Schottky Barrier diodes.
I'll look up the refernce you mentioned.

Thanks,
Steve

Title: Re: Charge Pump Design
Post by vivkr on Jun 28^th, 2010, 3:10am

Steve_S wrote on Jun 27^th, 2010, 5:58pm:

Hi Vivek,

Yes, the design we presently have is using Schottky Barrier diodes.

Thanks,
Steve

You are in a different game if you are using Schottky diodes. I thought you were talking about doing all these things on-chip. But if you are anyway making a discrete solution, then I would recommend using DC-DC converters with inductors. I haven't made any of those myself, but searching for boost DC-DC converters will probably get you a lot of links.

The text by Pan and Samadar is primarily concerned with IC solutions, and may not be relevant to your task.

Regards,
Vivek