# Bridgelux driver ?



## Axkiker (Aug 11, 2010)

Hey all I found this bridgelux array in another thread and it may work for my app.

What driver could I use in an automotive enviroment to drive 2 of these in parallel off a 12v battery.

http://www.newark.com/bridgelux/bxra...ray/dp/45P5610

thanks


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## Axkiker (Aug 11, 2010)

actually I got on the TASK led site and found this driver.

Anyone see a reason this driver wont work ????

http://www.taskled.com/techhboost.html


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## arek98 (Aug 11, 2010)

Hyperboost should be able to drive two of these but connected in series. It is also safer for LEDs, parallel connection from one driver is not recommended (due to Vf differences it is hard to tell which led will get what current). Also in series you will be able drive them to full 1.3A if you need to.
 
I think it will not work with one LED or two connected in parallel. 12V car battery is really about 14V or more for most the time (almost fully charged).
 
You would also need some kind of isolation from power source noise. I don't think Hyperboost will survive without some kind protection.


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## panicmechanic (Aug 11, 2010)

Too late


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## Axkiker (Aug 11, 2010)

arek98 said:


> Hyperboost should be able to drive two of these but connected in series. It is also safer for LEDs, parallel connection from one driver is not recommended (due to Vf differences it is hard to tell which led will get what current). Also in series you will be able drive them to full 1.3A if you need to.
> 
> I think it will not work with one LED or two connected in parallel. 12V car battery is really about 14V or more for most the time (almost fully charged).
> 
> You would also need some kind of isolation from power source noise. I don't think Hyperboost will survive without some kind protection.


 

Awsome.... so if im thinking correctly the hyperboost should be able to push 3 of them in series ?????

Doesnt look like it will do 4 unless I pull the Vf down a little

Now the whole isolation issue is a whole other deal I have to address.


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## arek98 (Aug 11, 2010)

Hyperboost will drive 5 of them in series easily. 6 may be over 80V limit. It is also pretty efficient even with big difference between Vin and Vf. However input current should not be bigger than 5A, so if you will have really big difference you will need to limit LED current. With ~12V Vin I would assume 3 LEDs is safe to run up to max (1.4A hyperboost, or 1.3A in case your LED). More LEDs and high current you will need higher Vin.

I used hyperboost to drive my under cabinet lights, 17 Seouls @700mA, 24V Vin and it does not even get hot.

You can limit output current with on-board trimpot, and if you want dimming you just buy 50kOhm pot and connect it to board (logarithmic is recommended), it will control current within range limited by on-board pot.

I'm not sure how you plan to use them but if you would prefer symmetrical setup the you can drive 4 and limit LED current to 1A (it is anyway higher that what you planned with parallel connection, and usually efficiency goes down with current, so you probably won't lose that much) and you should be good with 12V Vin. On the other hand given price of LEDs it may be more economical to get 2 and drive them harder. So many options...

Remember to plan some good heatsink for hyperboost at this voltage-current.

EDIT: I just noticed that LED is only $15, I was expecting more, so 4 may be a way to go.


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## Axkiker (Aug 11, 2010)

arek98 said:


> Hyperboost will drive 5 of them in series easily. 6 may be over 80V limit. It is also pretty efficient even with big difference between Vin and Vf. However input current should not be bigger than 5A, so if you will have really big difference you will need to limit LED current. With ~12V Vin I would assume 3 LEDs is safe to run up to max (1.4A hyperboost, or 1.3A in case your LED). More LEDs and high current you will need higher Vin.
> 
> I used hyperboost to drive my under cabinet lights, 17 Seouls @700mA, 24V Vin and it does not even get hot.
> 
> ...


 
Yeah im trying to figure out what is better for my application.... either 4 of the 1300 lm bridgelux arrays or one of the big 5000lm bridgelux arrays

Im glad you corrected me on the output capabilities of the hyperboost. I didnt see until I went back that it has a max of 80V output. So it does appear that i could easily drive 4 or 5 of the smaller bridgelux.


Now im back to a decision of is it better to run multiple leds or one big momma...

Building the housing and working with optics will be easier using one led. however the drivers etc needed are becoming a pain..


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## jason 77 (Aug 12, 2010)

Axkiker said:


> Yeah im trying to figure out what is better for my application.... either 4 of the 1300 lm bridgelux arrays or one of the big 5000lm bridgelux arrays
> 
> Im glad you corrected me on the output capabilities of the hyperboost. I didnt see until I went back that it has a max of 80V output. So it does appear that i could easily drive 4 or 5 of the smaller bridgelux.
> 
> ...



Well since the hyperboost driver says it maxes out at 1.4 amps output you wouldn't be able to use it to drive the 5000 lm bridgelux at it's test current of 2.1 amp.


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## Axkiker (Aug 12, 2010)

jason 77 said:


> Well since the hyperboost driver says it maxes out at 1.4 amps output you wouldn't be able to use it to drive the 5000 lm bridgelux at it's test current of 2.1 amp.


 

Yeah sorry I posted another thread about a driver i found on ebay that I "think" will power the 5000lm bridgelux possibly even 2.

Take a look and let me know what you think

Thansk


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## Axkiker (Aug 16, 2010)

arek98 said:


> Hyperboost will drive 5 of them in series easily. 6 may be over 80V limit. It is also pretty efficient even with big difference between Vin and Vf. However input current should not be bigger than 5A, so if you will have really big difference you will need to limit LED current. With ~12V Vin I would assume 3 LEDs is safe to run up to max (1.4A hyperboost, or 1.3A in case your LED). More LEDs and high current you will need higher Vin.
> 
> I used hyperboost to drive my under cabinet lights, 17 Seouls @700mA, 24V Vin and it does not even get hot.
> 
> ...


 

does the hyperboost come built in with the necessary equipment to run in an automotive enviroment.

ex: reverse polarity protection, voltage spikes etc????

Thanks


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## jason 77 (Aug 16, 2010)

Axkiker said:


> does the hyperboost come built in with the necessary equipment to run in an automotive enviroment.
> 
> ex: reverse polarity protection, voltage spikes etc????
> 
> Thanks



Doesn't really mention it anywhere in the notes... I would put a diode in for reverse polarity as well as maybe a 12 volt zener diode in for voltage spikes if you plan on using this driver...


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## Axkiker (Aug 16, 2010)

jason 77 said:


> Doesn't really mention it anywhere in the notes... I would put a diode in for reverse polarity as well as maybe a 12 volt zener diode in for voltage spikes if you plan on using this driver...


 

well I emailed taskled about the hyperboost and it does have reverse polarity protection but no voltage spike protection.

Can you explain a little about the zener diode being used..... Its been a LONG time since I had electronic classes.


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## Steve K (Aug 17, 2010)

a wonderful document from OnSemi about zeners and TVS (transient voltage suppressors). Tells you how they work, how to use them, etc. Used to be part of their zener databook when there were physical books....

http://www.onsemi.com/pub_link/Collateral/HBD854-D.PDF

page 44: ZENER PROTECTIVE CIRCUITS AND TECHNIQUES: BASIC DESIGN CONSIDERATIONS

Steve K.


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## Axkiker (Aug 17, 2010)

Steve K said:


> a wonderful document from OnSemi about zeners and TVS (transient voltage suppressors). Tells you how they work, how to use them, etc. Used to be part of their zener databook when there were physical books....
> 
> http://www.onsemi.com/pub_link/Collateral/HBD854-D.PDF
> 
> ...


 


Okay so let me see if im thinking correctly.

A zener diode will only allow electricty flow through a circuit up to a the cutoff point at which it was designed.

So lets take this setup im thinking about.

4 bridgelux led arrays ran in series
Vf 13.2
1.3A
1320LM


should give me a Vf of 52.8

if im doing the math correctly im looking at needing a zener diode that will handle roughly 69 watts with a cutoff voltage or roughly 53-54 volts.


if thats true where in the world do you find that at. I cant find anything that will handle anything near that power ?????


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## jason 77 (Aug 17, 2010)

Axkiker said:


> Okay so let me see if im thinking correctly.
> 
> A zener diode will only allow electricty flow through a circuit up to a the cutoff point at which it was designed.
> 
> ...



No you need a zener diode of only about 12 volts because you are using the hyperboost driver which you need to protect against a voltage spike and also against reverse voltage... "I think the data sheet says something like 80 volts max for the input of the driver"


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## Axkiker (Aug 17, 2010)

jason 77 said:


> No you need a zener diode of only about 12 volts because you are using the hyperboost driver which you need to protect against a voltage spike and also against reverse voltage... "I think the data sheet says something like 80 volts max for the input of the driver"


 
Okay that makes sense... I was thinking the diode would be placed in series after the hyperboost however it does make more sense to protect the hyperboost which will in tern protect the leds.


good call thanks


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## Axkiker (Aug 17, 2010)

so if im not mistaken this zener should work

http://www.newark.com/solid-state/1n3311b/zener-diode-50w-12v-do-5/dp/10P4804http://www.solidstateinc.com/specsearch/specs/1N3305-ssi.pdf


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## Steve K (Aug 18, 2010)

Axkiker said:


> so if im not mistaken this zener should work
> 
> http://www.newark.com/solid-state/1n3311b/zener-diode-50w-12v-do-5/dp/10P4804http://www.solidstateinc.com/specsearch/specs/1N3305-ssi.pdf



it does get difficult to absorb some of the long pulses, such as "load dump". Lots of energy in that, and it lasts fairly long. I've been partial to using a simple linear regulator (a zener regulator with a transistor as a current buffer) to just block any pulse. This requires the use of a transistor rated for 200v or so, and does end up wasting some power in the regulator. Depending on how it is designed, it could drop over a volt, and since you'll be drawing a few amps, you'll be dissipating a few watts. This will require heatsinking the transistor, etc.

A giant zener, such as you propose, has the advantage of not burning any power under normal circumstances (although I'd use a zener rated for at least 15v to avoid having it conduct under normal battery voltages). The giant zener does need heatsinking to handle the large pulses, though. 

Or... put a fuse in series with the power wire, don't heatsink the zener very much, and figure that the fuse will blow if you do ever get a big transient pulse. At least then you'll learn if the transients are a real threat. Fuses have their own set of headaches, though...

regards,
Steve K.


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## Axkiker (Aug 18, 2010)

Steve K said:


> it does get difficult to absorb some of the long pulses, such as "load dump". Lots of energy in that, and it lasts fairly long. I've been partial to using a simple linear regulator (a zener regulator with a transistor as a current buffer) to just block any pulse. This requires the use of a transistor rated for 200v or so, and does end up wasting some power in the regulator. Depending on how it is designed, it could drop over a volt, and since you'll be drawing a few amps, you'll be dissipating a few watts. This will require heatsinking the transistor, etc.
> 
> A giant zener, such as you propose, has the advantage of not burning any power under normal circumstances (although I'd use a zener rated for at least 15v to avoid having it conduct under normal battery voltages). The giant zener does need heatsinking to handle the large pulses, though.
> 
> ...


 
Well I thought about the fuse idea however I didnt know if they would blow fast enough. Heck its probably not a bad idea to put one in series anyway. 

I am a little confused as to why you need the zener if you have a fuse. Why not just use a 15v fuse. If they will catch the transients whats the purpose of using the zener???

thanks


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## Steve K (Aug 18, 2010)

Axkiker said:


> Well I thought about the fuse idea however I didnt know if they would blow fast enough. Heck its probably not a bad idea to put one in series anyway.
> 
> I am a little confused as to why you need the zener if you have a fuse. Why not just use a 15v fuse. If they will catch the transients whats the purpose of using the zener???
> 
> thanks



well, first you'll have to tell me how you think a fuse blocks/absorbs/shunts a voltage transient. To my knowledge, a fuse only stops large currents.

In my proposition, the purpose of the fuse is to limit how much energy the zener would have to absorb. This would allow a smaller zener package or zener heatsink.







This shows the arrangement I'm referring to.

regards,
Steve K.


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## Axkiker (Aug 18, 2010)

Steve K said:


> well, first you'll have to tell me how you think a fuse blocks/absorbs/shunts a voltage transient. To my knowledge, a fuse only stops large currents.
> 
> In my proposition, the purpose of the fuse is to limit how much energy the zener would have to absorb. This would allow a smaller zener package or zener heatsink.
> 
> ...


 
WOW im lost now LOL

I thought the Zener went in series with the leds???


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## Steve K (Aug 18, 2010)

Axkiker said:


> WOW im lost now LOL
> 
> I thought the Zener went in series with the leds???



The OnSemi zener notes aren't the easiest thing to read, especially as a beginner. Page 64 has the basic idea:
http://www.onsemi.com/pub_link/Collateral/HBD854-D.PDF

Zin would normally be some sort of resistance, but that would involve a steady loss of power. There is a resistance or impedance that is the result of the source of the transient, so an additional resistance might be overkill. The fuse is added to protect the zener and everything downstream in the event of a big transient.

FYI, the "load" shown on page 64 is your power converter (or linear regulator, etc.) plus the LEDs. I'm not sure why Fig 11a shows Vin as being the lower terminal on the left. Typo?

regards,
Steve K.


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## Axkiker (Aug 19, 2010)

Okay I think im dumber now than before.... LOL

Sorry guys its been a long time since i had any electronics classes and I wasnt even that good at it when I took them. LOL

So let me just ask this basic question and see if im going in the right direction

If I place a zener diode with a forward voltage of 15v / 50w in series with the driver for my leds... will that be sufficient to block out the evil transient voltages etc in an automotive electrical system


Thanks


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## Steve K (Aug 19, 2010)

Axkiker said:


> If I place a zener diode with a forward voltage of 15v / 50w in series with the driver for my leds... will that be sufficient to block out the evil transient voltages etc in an automotive electrical system



in the interest of clear communication, you might want to draw the circuit you are referring to, but putting a zener in series with the driver will only mean that you'll need an extra 15v to get current to flow to the driver. For a 12v battery, that means the leds will light only if there is a transient voltage. It also means that it doesn't protect the driver from a big transient.

The standard way to protect a load from transients is shown from the OnSemi application notes, and (more or less) by my schematic.

Steve K.


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## Axkiker (Aug 19, 2010)

Hold on I think I have been thinking backwards the entire time. 

The zener only passes current when spikes occur above its preset limit..... So thats why the zener is not in series. Its connected to ground so that it closes anytime there is a spike above 15v and passes it to ground.... therefore protecting the equipment.


HAHAHa I was thinking the opposite. I thought the zener opened anytime a spike occured... almost like a switch shutting off. 

am I on track

Now your diagram makes perfect sense.


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## Axkiker (Aug 19, 2010)

Okay now I understand why you say I can use a smaller zener.

With that said what size zener would you recommend. fuse wise would you say take the input current and add 20% to it.


HHAAHHA the light just came on.


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## Steve K (Aug 19, 2010)

Axkiker said:


> Okay now I understand why you say I can use a smaller zener.
> 
> With that said what size zener would you recommend. fuse wise would you say take the input current and add 20% to it.
> 
> ...



A 20% margin may not be enough. It wouldn't hurt to check the fuse mfgr's web site and see how they recommend sizing fuses. Then check the fuse size by running the light for a couple hundred hours in hot conditions?? If the led driver is a switching regulator (boost or buck), then run it at low supply voltages. That should make it draw the most current.

You'll probably want to see if the zener & fuse are actually catching or clamping the transients. Some of the worst transients in a car are generated when the engine is running, and a large electrical load is removed. This might done by turning the headlights on and off when the high beams are selected.

Other ways to generate transients: honk the horn, turn the heater/AC fan on and off.

that ought to cover the basics....

regards,
Steve K.


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## Axkiker (Aug 20, 2010)

Steve K said:


> A 20% margin may not be enough. It wouldn't hurt to check the fuse mfgr's web site and see how they recommend sizing fuses. Then check the fuse size by running the light for a couple hundred hours in hot conditions?? If the led driver is a switching regulator (boost or buck), then run it at low supply voltages. That should make it draw the most current.
> 
> You'll probably want to see if the zener & fuse are actually catching or clamping the transients. Some of the worst transients in a car are generated when the engine is running, and a large electrical load is removed. This might done by turning the headlights on and off when the high beams are selected.
> 
> ...


 

Any thoughts on what size zener to use... Since it will only be passing current when there is a spike I assume a much smaller zener is okay to use as long as you add a fuse as well 

any thoughts.


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## Steve K (Aug 20, 2010)

Axkiker said:


> Any thoughts on what size zener to use... Since it will only be passing current when there is a spike I assume a much smaller zener is okay to use as long as you add a fuse as well
> 
> any thoughts.



I think I'd try a 3 or 5 watt zener. About 15 to 18v, depending on what input voltage your led driver can tolerate. If need be, you can run a couple of these zeners in parallel to increase the power rating (although this isn't the best approach, it's pretty good).

On the plus side, if the transients are too big and kill the zener, zeners usually die as a short. The short will blow the fuse. You can then check the zener with a meter to see if it is shorted. If it is, add another zener in parallel with it.
Seems like a good plan. :thumbsup: :duck:

regards,
Steve K.


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## Axkiker (Aug 20, 2010)

Steve K said:


> I think I'd try a 3 or 5 watt zener. About 15 to 18v, depending on what input voltage your led driver can tolerate. If need be, you can run a couple of these zeners in parallel to increase the power rating (although this isn't the best approach, it's pretty good).
> 
> On the plus side, if the transients are too big and kill the zener, zeners usually die as a short. The short will blow the fuse. You can then check the zener with a meter to see if it is shorted. If it is, add another zener in parallel with it.
> Seems like a good plan. :thumbsup: :duck:
> ...


 

Awsome

I was currious what happened when a zener died.... The 5 W versions are cheap and easy to find.

We have a plan

Thanks


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