Voltage multiplier circuit required

[(*steve*)]

That's a pretty good chip. I recall some time ago that Dave Jones made an EEBlog video of his search for a boost regulator that would operate from low voltages.

Rather than me take the credit for indicating how you could search for one, you could watch his video.

I believe he makes good use of the digikey parametric search. It's a great resource even if you don't buy stuff from Digikey.

Now, as to whether 2 stages is a good idea, it does mean you're multiplying your losses, which is never a good thing. However I wouldn't say it would never be an appropriate solution. However, if you can manage to get an inverter operating, a flyback device is well suited to large increases in voltage. The drawback is that it requires a transformer rather than a simple inductor thus increasing volume and expense.

 

[Mongrel Shark]

You know that might just do it. I have a fly-back i salvaged out of an old TV (Use EXTREME caution if you try this! Cathode Ray Tubes are super deadly if you don't understand the dangers) I have been trying unsuccessfully to make a high voltage transformer Joule Thief type arrangement (I added extra windings to the exposed ferrite). I know it can be done though.

I've seen 12v turned into 125kv this way. So no reason you couldn't turn .5v into 12v. It's a tiny step up in comparison...

I hope srisms comes back. I'm keen to see if we have been able to help.

 

[BobK]

The big problem with the 0.5V is that you cannot operate transistor switches from this voltage. So I think Steve had the right idea. You need a low power source just to get the control voltage to operate MOSFETs. A Joule Thief might actually work for that part, or you could even use a rechargeable battery. Then you use a full bridge inverter with the high current 0.5V input, getting 1V p-p on a transformer. If using a battery, it could be recharged from the output.

Bob

 

[Mongrel Shark]

Rather than me take the credit for indicating how you could search for one, you could watch his video.

I just finished watching the video. It's a long one at over an hour, and 150mb+ off your internet if that's a factor. But it was thoroughly worthwhile! There are tons of traps a new hand could fall into. After watching the video I feel much better equipped to search for all sorts of components. Not just DC-DC step ups.

Highly recommended viewing.