DIY: SSL complete protection for two LED drivers

Oh and another important note ,regarding the schematics posted here...

When you see the "ground " symbol ( an arrow made of 3 lines ,GND ) is not the MAINS EARTH .
It is the "minus" side of the 12 VDc fan power supply unit .

In fact you do not want the earth from mains
to short / contact with the 0 VDC ( aka the analog DC ground ) .

You should keep the AC circuitry ( Neutral , Earth & Line/Live ) well isolated ,
from the DC circuitry ( +12 VDC & Ground or 0 VDC ) .

Cheers.

stardustsailor said:

Easier to use than the LM2907 / LM2917 ,but yes ...
6 volt max Vcc ....
Probably it better "fits" to a motherboard ,rather to a LED grow light ..


About the one driver + 3 fans combo ....
The schematic can be like that ..( ido not see any problem why it shouldn't work ...
But the trained & far more experienced eye of Guod, might be seeing something I've already missed or did not even know about ... )
View attachment 3475029

One relay ,3x LM2907 ,one for each fan ...
At the zip folder ,the DipTrace pcb file for a single driver-single fan .

Cheers.

Click to expand...

Thank you again, can I ask what software you use for your schematics?

CanadianONE said:

Thank you again, can I ask what software you use for your schematics?

Click to expand...

....DipTrace ....


It has 4-sub-programs ,in fact ...

"Schematic Capture " used to draw schematics .
(DipTrace then ,can automatically "transform" them into PCBs .Never used that feature.
Designing a pcb from scratch is pure fan .)

"PCB Layout" used to make the pcbs .
(DipTrace then ,can automatically "route" the traces between components .Never used that feature.
Routing the traces in a pcb from scratch is pure challenge ,way better than Spider Solitaire with all four suits ...)

"Component Editor "can be used to design your own schematic symbol .

And " Pattern Editor " can be used to make your own pcb component patterns .
(used it couple of times.I have made solder pads for the tiny Osram Oslon LEDS ,
with large area copper pours for the center thermal Pad actually,
in order to make my own DIY metal-core pcbs ,so to solder the Oslons onto .
Used my oven as a reflow soldering station.That had not so much fun.
Pain everywhere ,not just in the ass.Especially my fingers,which where "well-done" ,
plenty of times.

Cheers.

stardustsailor said:

....DipTrace ....

Click to expand...

OK perfect. I have diptrace also just started playing around with it. Going to see if I can recreate your schematics for some practice lol

Law #1 of Electronics:

R T F M



Cheers.

stardustsailor said:

....DipTrace ....
View attachment 3475048

It has 4-sub-programs ,in fact ...

"Schematic Capture " used to draw schematics .
(DipTrace then ,can automatically "transform" them into PCBs .Never used that feature.
Designing a pcb from scratch is pure fan .)

"PCB Layout" used to make the pcbs .
(DipTrace then ,can automatically "route" the traces between components .Never used that feature.
Routing the traces in a pcb from scratch is pure challenge ,way better than Spider Solitaire with all four suits ...)

"Component Editor "can be used to design your own schematic symbol .

And " Pattern Editor " can be used to make your own pcb component patterns .
(used it couple of times.I have made solder pads for the tiny Osram Oslon LEDS ,
with large area copper pours for the center thermal Pad actually,
in order to make my own DIY metal-core pcbs ,so to solder the Oslons onto .
Used my oven as a reflow soldering station.That had not so much fun.
Pain everywhere ,not just in the ass.Especially my fingers,which where "well-done" ,
plenty of times.

Cheers.

Click to expand...

Thankfully I have a hot air solder station if I need to do any re-flow work

The current requirements is small for the maxim IC
Will a LM7806 or LM7805 be enough to power it without any heatsink to the LM
Assuming we use fan 12V

From my understanding it would require a heatsink. PD = (VIN – VOUT) * IOUT therefore (12v-5v)x 0.3a = 2.1 watts.
Trise = PD * RθJA therefore 2.1 watts x 65 C/W = 136.5 degrees Celsius. Datasheet for LM78XX states maximum operating temperature of 125 degrees Celsius.

https://www.exar.com/common/content/document.ashx?id=1225

https://www.fairchildsemi.com/datasheets/LM/LM7805.pdf

http://datasheets.maximintegrated.com/en/ds/MAX6684.pdf

Also we need to consider the fact that a linear regulator is very inefficient. Hope my math is correct. Someone correct me if I am wrong.

Thanks for help with the calculations.
0.3 or 300 ma for fan.
i think the IC need only 3.4 ma
so (12-5)*0.0034= 0.024watts
0.024*65=1.5 degree C

robincnn said:

Thanks for help with the calculations.
0.3 or 300 ma for fan.
i think the IC need only 3.4 ma
so (12-5)*0.0034= 0.024watts
0.024*65=1.5 degree C

Click to expand...

Your right, I took the wrong figure from the data sheet. If fan is pulling 300ma then IC will need 3.4ma. Just learning and figured I would take a stab at it lol

Ok ,since you're interested with that kind of low voltage ICs for fan protection ,here's another one :

http://ww1.microchip.com/downloads/en/DeviceDoc/21688c.pdf

" The TC670 is an integrated fan speed sensor that
predicts and/or detects fan failure, preventing thermal
damage to systems with cooling fans. When the fan
speed falls below a user-specified level, the TC670
asserts an ALERT
signal. With this design, a critical
minimum fan speed is determined by the user. "

" consumes 90 μA (typ.) during operation. "

" VDD Range 3.0V to 5.5V "

" Available in a 6-Pin SOT-23 Package "

I guess it needs a PNP ( like 2N3906 ) to switch ON /OFF a 5 VDC relay .

With an ALERT CLEAR / RESET button switch ...
Hmmm...

Talking about ridiculous mistakes ..I'm an idiot ...
The schematic above could work ,if the relay was a double throw ...
At normally closed state the LED drivers are switched ON ...
When Alert output goes LOW ,then the transistor will energize the relay
and the LED drivers will switch OFF . ( Relay wiper is shorted with Normally Open pin ,now )
So while the circuitry is not actually wrong ,the relay symbol is ...
You will need a double throw relay ,not a single throw as pictured ..

Still it can work with a NPN transistor also .
Pull up the base to +VDC with a pull up resistor and when ALERT goes LOW ,
transistor opens ,deactivating the relay ..
At this case connection of the relay is opposite than before .
LED driver is connected to Normally Open pin of the relay .

So ..PNP =driver connects with NC relay output
NPN = driver connects with NO relay output

Ehmmm ...Ain't that right ?

(Please,give me some "slack" for mistakes ..I had a rough night ... )

Cheers.

stardustsailor said:

Talking about ridiculous mistakes ..I'm an idiot ...
The schematic above could work ,if the relay was a double throw ...
At normally closed state the LED drivers are switched ON ...
When Alert output goes LOW ,then the transistor will energize the relay
and the LED drivers will switch OFF . ( Relay wiper is shorted with Normally Open pin ,now )
So while the circuitry is not actually wrong ,the relay symbol is ...
You will need a double throw relay ,not a single throw as pictured ..

Still it can work with a NPN transistor also .
Pull up the base to +VDC with a pull up resistor and when ALERT goes LOW ,
transistor opens ,deactivating the relay ..
At this case connection of the relay is opposite than before .
LED driver is connected to Normally Open pin of the relay .

So ..PNP =driver connects with NC relay output
NPN = driver connects with NO relay output

Ehmmm ...Ain't that right ?

(Please,give me some "slack" for mistakes ..I had a rough night ...

)

Cheers.

Click to expand...

Your opinion do you think this could be a better solution for my situation with three fans and single driver. I will cut you all the slack you need because your input on this is invaluable

CanadianONE said:

Your opinion do you think this could be a better solution for my situation with three fans and single driver. I will cut you all the slack you need because your input on this is invaluable

Click to expand...

Well, all the three ICs explored at this thread ,more or less ,do the same job ...
They operate as speed switches ...
Making a "market research " will reveal ,which IC of them you can obtain easily and with a low price ...
Of course SO-8 and SOT-23 are tiny chips (at least compared to DIP-8 =>LM2907N-8 or LM2917N-8 )
and could save considerable PCB space.
Still you will need a sub-circuit to power them ( LM7805 ,LD1117) ,
but they need somewhat less external components than the LM29x7 ,in order to "set" them ...
And they seem more "maker -friendly" ,also ..

LM29x7N-8 is a very versatile IC ,with a Vcc up to 28VDC ,
but not so "friendly" to "set " ...
It can drive directly a relay .
It operates only with 3 or 4 wire fans (TACH wire )

The other two ,are of "low -voltage " ( TTL level =3.3-5 VDC ) ICs ,
They match with microcontrollers perfectly for more advanced designs ,
they consume less energy( as ICs ) ,they are more "dedicated" fan fail protectors ,
they work with ordinary two-wire fans also.
And they are smaller in size ..

First thing ...
Check for availability and prices ...*
Then you decide which way you will follow...
( Usually I take couple more pieces , than I need ..
Having some spares ,is a good thing ... )

Cheers.

Here's a pic for size comparison ..
A single driver LM29017N-8 fan fail protection pcb.
( with built in +12VDC remote trigger output ,for powering a "turn on delay" circuit for a second LED driver )
Besides an Arduino UNO board ...

( Usually I use 1206 SMD resistors & caps as also SMD diodes ,
but at this case I've used ordinary through-hole parts.
All caps are Solid Tantalum ,except the large " transient smoothing " electrolytic one
and all resistors used are of 1% tolerance )



Cheers.

stardustsailor said:

Here's a pic for size comparison ..
A single driver LM29017N-8 fan fail protection pcb.
( with built in +12VDC remote trigger output ,for powering a "turn on delay" circuit for a second LED driver )
Besides an Arduino UNO board ...

( Usually I use 1206 SMD resistors & caps as also SMD diodes ,
but at this case I've used ordinary through-hole parts.
All caps are Solid Tantalum ,except the large " transient smoothing " electrolytic one
and all resistors used are of 1% tolerance )

View attachment 3475459

Cheers.

Click to expand...

Great size comparison. I can easily get any of the three IC's discussed through mouser. The LM29*7N-8 both $2.45/1, $1.97/10. The TC670ECHTR is $1.83/1 $1.72/10 $1.44/25
So the TC670 is a little cheaper. But I also like the fact that you say it used less components to put the circuit together & the fact it can be used for 2 wire fans also. Another fact I like about it is the fact that it can be matched with micro controllers for more advanced designs later on. I have a good solder station as well as hot air station so I don't think soldering the smaller IC would be of concern.

CanadianONE said:

Another fact I like about it is the fact that it can be matched with micro controllers for more advanced designs later on.

Click to expand...

The LM29*7N-8 has an open collector output, connecting to a micro controllers iis simple.

sensing 3 fans in one light, my brain starts to think about an Attiny45/85.
hmm... 4 resistors, 3 caps, one transistor,something to get the right voltage....

....more red vine please... i have to think

guod said:

The LM29*7N-8 has an open collector output, connecting to a micro controllers iis simple.

sensing 3 fans in one light, my brain starts to think about an Attiny45/85.
hmm... 4 resistors, 3 caps, one transistor,something to get the right voltage....

....more red vine please... i have to think

Click to expand...

......


The world is so ...
Funny thing ,my dear brother ...
I'm having some red wine ...
Actually about a liter of the finest red wines around ..
Please,let us enjoy ..
Our red wine .....
And our ideas...
Of course ,myself I'm most interested for yours.

..
Yes,you;re absolutely right ...
My favourite for sure .
The LM29*7N-8.

I've to say ,that the reason ,I stated ,that the other two ,are more
familiar to the MCUs ,was/is the ability that they offer -easily-to reset their
"latch" state with an external TTL level signal.
Yes,you can do that with LM29*7 also ...
( A NPN transistor ? collector to pin 4 ,emitter to pin 3,base to MCU ?
Latch as shown at the AN for the LM29*7 ? )

Anyway ....

More red wine ...

And
....
To Light !

Cheers!, my brothers !!!



P.S . Guod,my brother,of course you are now "obligated" -sort of speaking
to post a tad more this time ....
The Attiny45/85. way....


.

...cheers Guod...SDS...and cia...

pd...lot of good good wines here... red -north ...white-south... but expensives too...

guod said:

The LM29*7N-8 has an open collector output, connecting to a micro controllers iis simple.

sensing 3 fans in one light, my brain starts to think about an Attiny45/85.
hmm... 4 resistors, 3 caps, one transistor,something to get the right voltage....


Drink up my brothers, @guod I like where your going with this. I am glad you gentlemen are around. I have no issue building a circuit and doing all the necessary soldering, But to actually design an efficient working circuit is almost beyond me lol

....more red vine please... i have to think

Click to expand...