Zetex 310 based boost converter with 1 amp output.

ARC mania

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It seems that a lot of people think that the Zetex 300/310 driver is out of date or can only drive a Lux 1 at 1.5 watts from a single CR123. NOT! The Zetex 300/310 is far more advanced than you think as well as being ahead of its time. So far I have made a buck/boost converter using the Zetex 300 which has an input of 2 to 6 cells and a output of 550ma. I don't want to get into too much detail of this converter at the moment. I have made a boost only version (maximum input is 3.2 volts) which has an output of 1 amp when driven from a single CR123 battery. The problem here is that within 5 minutes, the battery will go into safe mode and thermally shut down. When output was set to 780ma, it had no shut down problems. So, gpk, I guess this answers your question. I will let pictures do the talking. I will do a small run of these converters in the near future, actually after I finish shipping out all the Katokichi CR2 flashlights....

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Doug S

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Due to the limited base drive current available from the IC, it seems that you would need to go to a Mosfet switch instead of a BJT to achieve these high current levels. The required gate drive voltage for even low Vgs Mosfets would seem to preclude single alkaline cell versions unless you included an additional gate driver that bootstrapped off of the output voltage. With a single CR2 or CR123 there are now some pretty low resistance Mosfets that will operate at these gate voltages. I think I would still be tempted to add a gate driver IC to reduce switching losses at these high currents. There are some nice tiny single gate logic ICs that should do nicely for that function.
 

ARC mania

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Doug,

Yes, you pretty much have the idea correct. I'll have the photo up soon. The picture will show an NPN as it was the prototype but the ones for sale in the future will utilize a low on resistance trench mosfet. There is a smaller transistor which will help kick start the mosfet. I'm having problems posting pictures........



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Doug S

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Mike, I'm looking forward to your pictures. I still consider your orginal micro-converter to be a work of art. In it's size range it's the best I've seen. I particularly liked that technique you used of biasing the Rsense input with a some fraction of the input voltage to flatten its I/O characteristics a bit.
 

ARC mania

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Doug,

Thanks. Can you post pictures? I hate to ask you this but I'm having all kinds of problems, if you can post the picture, can you PM me your e-mail address? Thanks again.

ARC mania
 

Doug S

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[ QUOTE ]
ARC mania said:
Doug,

Thanks. Can you post pictures? I hate to ask you this but I'm having all kinds of problems, if you can post the picture, can you PM me your e-mail address? Thanks again.

ARC mania

[/ QUOTE ]
Mike, I don't have any webspace for picture hosting. I recall that one or more CPF members have offered some of their webspace in the past for picture hosting. It will require a bit of searching to find out who. Alternately you could PM CPF member B@rt, our tulip sniffing administrator who seems to stay current on the best available *free* picture hosting that is available.
 

flashlight

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[ QUOTE ]
ARC mania said:
wasabe64,

Thank you for posting the pictures.

Board width is: 14mm and thicknss: 1.6mm

ARC mania

[/ QUOTE ]

Ah, wasabe64 beat me to it. Sorry Mike just got back /ubbthreads/images/graemlins/grin.gif
 

Doug S

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[ QUOTE ]
ARC mania said:
Board width is: 14mm and thicknss: 1.6mm

ARC mania

[/ QUOTE ]
Mike, is that 1.6mm thickness the bare board only? The overall thickness of board plus components looks to be greater in the photo.
 

gpk

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Pretty damn cool! Ohh I see the infamouse 617 there /ubbthreads/images/graemlins/smile.gif
Can it be driven to ~750 using 2 x NIMHA cells (2.4-2.74 V?
Looking forward to hearing more...

gpk
P.S. Just out of curiosity; what will you be selling the board for?
 

McGizmo

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Re: Zetex 310 based boost converter with 1 amp out

Mike,

It looks cool even though I have no clue what I am seeing! /ubbthreads/images/graemlins/blush.gif

/ubbthreads/images/graemlins/thumbsup.gif
 

cy

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Re: Zetex 310 based boost converter with 1 amp out

mike, great job!! would like to get a few boards. Please PM when ever you are ready.
 

Doug S

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Re: Zetex 310 based boost converter with 1 amp out

I have exchanged a few PM's with Mike about assembly of this board. The truly amazing thing is that he assembles these by hand without the aid of a microscope! He says that a microscope slows him down too much! Note that in the photo, the alignment of all the components is perfect. Mike probably should have been a micro-surgeon instead of an engineer.
 

ARC mania

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Re: Zetex 310 based boost converter with 1 amp out

gpk: Yes, you can obtain an output of 750ma using two AA
size NiMH batteries rated at 2000mah or above. I do
have any idea of pricing at this moment.

cy: Thanks, will do.

NewBie: Efficiency is around 89%

ARC mania
 

MrAl

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Re: Zetex 310 based boost converter with 1 amp out

Hello,

Interesting thread!

Back when we first talked about the Zetex circuit, we
talked about running higher power LED's (more than
350ma) and we came to the conclusion that it could be
done at the expense of efficiency and run time.

I just have to say that 89 percent sounds a *little* too
high /ubbthreads/images/graemlins/smile.gif although im sure the circuit is still very
useful.


Take care,
Al
 

Ralf

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Re: Zetex 310 based boost converter with 1 amp out

What are these devices between the 617 and the Zetex310?
I built a 310 based step up by myself and just used
the application from the datasheet ...

Cheers
Ralf
 
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