Dynamo LED Driver Circuit - PCB available

[Martin]

Oh, I do. Quote from my website:
"The driver circuits are not affected by the type of LED used, as long as it has the typical forward voltage of a white LED."

 

[robdeanhove]

Martin - are you still offering the circuit boards for sale to fit into the fork steerer? If so, I'd love to buy three of them please.

Thank you

Rob

 

[ktronik]

Martin - are you still offering the circuit boards for sale to fit into the fork steerer? If so, I'd love to buy three of them please.

Thank you

Rob

If Martin is out of stock, I have stock, but only if martin has no stock...

best

K

 

[Savvas]

If Martin is out of stock, I have stock, but only if martin has no stock...

best

K

Hi ktronik,
First post so I hope I'm doing this correctly!
It appears from your post late last year (or rather the lack of response) that Martin has no more of these boards available. Do you have any stock? Is it possible for me to purchase a couple from you? I'm in Adelaide. How do I contact you?
Thanks,
Sam.

 

[Martin]

Hi Savvas, depending on how many you need, I may be able to help you. Find my e-mail address on pilom.com

Martin

 

[seanspotatobusiness]

At Martin's website it says that two variations of circuit 12 "were created to avoid the current surge that occurs in circuit 12 when switching from bridge rectifier to voltage doubler mode". How large a surge is this?

Does Circuit 12 negate the need for a driver such as this?

My mind is awash with circuits and implications that I can scarcely understand!

 

[Martin]

At Martin's website it says that two variations of circuit 12 "were created to avoid the current surge that occurs in circuit 12 when switching from bridge rectifier to voltage doubler mode". How large a surge is this?

I have explained this in the downloadable documentation of the project. It won't do any damage but some users found it triggered the overvoltage crowbar. The fix is making the crowbar less sensitive.

Does Circuit 12 negate the need for a driver such as this?

Yes. The same goes for circuit 1, 2, 3, ... on my page.<BR>
By the way, the LED driver module that your link points at is NOT for use with a dynamo but with a battery.

My mind is awash with circuits and implications that I can scarcely understand!

Several of the simpler circuits will give you plenty of light, so take your time.

 

[steveg0906]

Hi guys first post I am trying to get a couple of pcb boards for a hub generator, I tried matins email from pilom but its not working. any help
would be appreciated

thanks Syeve

 

[seanspotatobusiness]

I came back to ask a question about Martin's circuit but I imagine anyone can answer if they understand better than I do - the smoothing capacitor in circuit 2 onwards - Martin suggests a capacitor capable of at least 4V but I don't understand this because the dynamo is capable of supplying 6V RMS, peaking at >8V, right? Wont that be too much for an capacitor capable of less than 6 (or is it 8??) volts?

Also, capacitors C2 and C3 have to be of low ESR. How low? Is 0.287Ω (electrolytic) low enough? Here is a ceramic capacitor for which the ESR is not stated. Are they automatically assumed to be low or high?

Hi guys first post I am trying to get a couple of pcb boards for a hub generator, I tried matins email from pilom but its not working. any help
would be appreciated

thanks Syeve

Maybe he just needs time to get back to you? In any case, he frequents this very thread so maybe you'll get a reply here.

Several of the simpler circuits will give you plenty of light, so take your time.

Thanks, Martin. I'm now trying to hybridise your 6th circuit with something of Steve K.'s which should make some low-power 5mm LEDs switch on when my speed drops too low to light the Cree LEDs (or when I'm stationary). They'd be powered by a NiCd AA battery which would be kept charged by the circuit.

 

[Martin]

I came back to ask a question about Martin's circuit but I imagine anyone can answer if they understand better than I do - the smoothing capacitor in circuit 2 onwards - Martin suggests a capacitor capable of at least 4V but I don't understand this because the dynamo is capable of supplying 6V RMS, peaking at >8V, right? Wont that be too much for an capacitor capable of less than 6 (or is it 8??) volts?

Trick question: What current will that 6V dynamo drive through the single LED ?

Also, capacitors C2 and C3 have to be of low ESR. How low? Is 0.287Ω (electrolytic) low enough?

0.287 R is not bad at all. Make sure you maintain it over the full operating frequency range.

Here is a ceramic capacitor for which the ESR is not stated. Are they automatically assumed to be low or high?

Ceramic caps are always low and would be great for this application, if only one could find the required capacity x voltage. The part that you have linked has an impressive 4700uF capacity at 100V, impossible specs for a ceramic, clearly an error in the RS catalog.

Hi guys first post I am trying to get a couple of pcb boards for a hub generator, I tried matins email from pilom but its not working. any help
would be appreciated

thanks Syeve

What's the error that you get ? Have you double-checked the spelling ? I'm periodically checking the mailbox and can't find anything wrong with it now.

 

[seanspotatobusiness]

Trick question: What current will that 6V dynamo drive through the single LED ?

Hey Thanks, but I don't understand the relation... at 6V and 3W, the current must be 0.5A? Wrong? Why?? I remember reading something about the dynamo being a current source, so it's voltage is flexible... is that what you're saying? But if I have two power LEDs in series, then don't I need a capacitor with more than 4V rating?

0.287 R is not bad at all. Make sure you maintain it over the full operating frequency range.

If I understand the datasheet right, the frequency has to be at least 100 Hz. This will be fine once I reach travelling speed, but there will be an intervening period during which the dynamo is rotating much more slowly - would that be a problem for the circuit?

Can you explain that part of the circuit is actually doing? I know it's supposed to "boost power over intermediate speeds" but I don't see how. I've asked elsewhere and get different answers.

 

[steveg0906]

Hi Martin I tried your Email again I think it went thru. i must have typed it wrong the first couple times. i am trying to get a couple of pcb boards
for a hun generator any help would be great

Thank Steve

 

[Martin]

Right. Dynamo current is 500 .. 600 mA and the voltage across the LEDs is whatever your LED-string drops at this current (datasheet). With a single white LED this is around 3.5 V

I cannot tell you how much margin there is in the capacitor spec in your case. May I suggest that you just use any new low-ESR capacitor with my recommended capacitance and voltage. This way you will most likely achieve happiness.

 

[seanspotatobusiness]

Okay, thanks again

 

[seanspotatobusiness]

Hi again Martin, I was just wondering, if I was to use a non-polarised 220uF capacitor (that would actually be cheaper for me), instead of two low-ESR capacitors (as per Circuit 5), would the required voltage still be 63V or something different? Thanks

 

[Tricky Dave]

Hi Martin

Fantastic work- are boards still available?

Dave

 

[dogxcd]

hi
i would v much appreciate the opportunity to but 2 of the pcbs please
if anyone has some for sale,cld they pm me please?
regards
d

 

[BrianMc]

PM Martin. I got two from him a year ago.

BrianMc