Die4Drive (low side drive) and red diodes (high side can)

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08-10-2010, 02:12
Zoof

Die4Drive (low side drive) and red diodes (high side can)

When the case of the red diodes is connected to 5v and not electrically insulated it gives some inconvenience in isolating the red module from the projector's base plate that is grounded.

To circumvent this, can we not simply connect the drivers high side to the base plate (0V) and connect the driver's low side to a -5V supply? The driver still sees a 5V voltage supply and the case of the red module will have the 0V base plate potential, eliminating the need for electrical insulation.
I don't see a problem with this.

It introduces an inconvenience with the modulation signal (0 to 5v) which will be 10V higher than the -5V low side of the driver.
How can we bring the modulation signal in the -5v to 0V range? or will it introduce a bigger hassle than isolating the whole module from the base plate?

thanks,
Matthijs
08-10-2010, 02:39
andy_con

just a thought but wouldnt it be easier to insulate each diode.

saves lots of messing around with the driver etc
08-10-2010, 04:00
dave

Quote:

Originally Posted by Zoof

How can we bring the modulation signal in the -5v to 0V range? or will it introduce a bigger hassle than isolating the whole module from the base plate?

It would be menial to offset the modulation signal. Nothing that cant be done with a opamp or 2 :)

Nice idea BTW!
08-10-2010, 04:02
dave

Quote:

Originally Posted by andy_con

just a thought but wouldnt it be easier to insulate each diode.

Personally having messed around insulating the diode the way Simon and you do it, I am over it. I honestly don't like working with glues that come with carcinogen warnings..
08-10-2010, 04:06
andy_con

Quote:

Originally Posted by dave

Personally having messed around insulating the diode the way Simon and you do it, I am over it. I honestly don't like working with glues that come with carcinogen warnings..

i was suggesting that as such, just didnt know if using some of the tapes and thing people use would be easier.

but if modding the driver as such works then great please post details as im interested.
08-10-2010, 05:42
drlava

I don't think it would work as you describe. It could be wired this way with additional modulation offset correction, however the diode anode would be connected to 0V and the cathode (the case connected pin) would now be below 0V, not at 0V. This is a less dangerous situation, but still requires diode isolation. The other solution is to just use a high side driver, there have been a few posted including the FlexMod P3.
08-10-2010, 05:44
dave

Actually, nope, that wont work as the diodes case is cathode, not anode.. Just use a high side driver like the new P3 or Andy's driver..
08-10-2010, 06:51
Zoof

quite right, it won't work, thanks for pointing that out....
08-22-2010, 05:48
mccarrot

Hi Zoof,

Johan, (Edison) got 4 of andy's highside drivers from me. Now he received the 6 ch RBLD driver with tec he will not be using the boards anymore i quess.

You can buy some of those drivers from me for cost price.

regards,

Maurice.
08-22-2010, 07:58
edison

i still use one. I will pay the one that i use now. Let me know what the price what i have to pay for that one so i can send the other ones directly to zoof. if he wants the drivers.:)
08-22-2010, 22:11
dave

I still have heaps of unbuilt boards if anyone wants them :)
08-22-2010, 22:12
dnar

I ran in to this problem recently. My solution was to drive the DPPS with an isolated DC-DC converter (followed by an LD driver), and used a Darlington opto-isolator on the TTL drive. The entire DPPS drive is ground isolated, yet high side bonded to chassis through the laser module.
08-23-2010, 14:52
megaton

Quote:

Originally Posted by dave

I still have heaps of unbuilt boards if anyone wants them :)

Hi Dave

What this board does? driver or tec cooling?
I'm interested now in both and color correction also.

Thanks
Eduardo
08-24-2010, 05:17
dave

Its just a high side driver ( common cathode )

:)
08-24-2010, 19:44
megaton

Interested in 10Pcs.
How much?

:)
08-25-2010, 07:57
p1t8ull

Totally agree Dave, but it did enable us goofs to crack on whilst you electronic geniuses perfected the high side driver thingy :p

Seriously, these are great little boards and will be powering my 642 diodes as soon as I can get onto it :)

Quote:

Originally Posted by dave

Personally having messed around insulating the diode the way Simon and you do it, I am over it. I honestly don't like working with glues that come with carcinogen warnings..
08-31-2010, 17:32
catalanjo

Quote:

Originally Posted by dave

I still have heaps of unbuilt boards if anyone wants them :)

I want some pls :D
PM on it''s way.
Cheers:)