LED Driver alternative

[plugsandsparks]

If you are going for that type of form factor (they would typical be inside a linear light fitting, then why not

Tridonic Non-SELV 100W Constant Current LED Driver (250-700mA)

An IP20 rated constant current LED driver from the Tridonic EXCITE Non-SELV series. This driver is IP20 rated and has an adjustable output current between 250 and 700mA.

www.bltdirect.com

8.33K resistor gives 600mA same minimum voltage so no downside

 

[Lucien Nunes]

E2A: see posts below, the following might be incorrect due to the differences between Gen 1 & 2 configuration.

I am not convinced that the LED is presently running at 605mA. The Osram LEDset guide gives the resistor value as:
Rset [Ω] = (5 V/Iout [A]) x 1000
For 605mA that would be 8.3kΩ and although I can't see the colours on that resistor clearly enough to say what the value is, it doesn't look like 8.2 kΩ. The band that Brian sees as green, I see as blue, which would make it 16kΩ leading to a lamp current of 310mA, i.e. it might be significanly underrun (which could be a factor in the LEDs all outlasting the drivers.) I would want to double-check that before choosing an alternative driver.

 

[brianmoooore]

The band that Brian sees as green, I see as blue, which would make it 16kΩ leading to a lamp current of 310mA,

I see that band as a blueish green or a greenish blue. Could be either TBH, but 15k is the standard value, although 16k is in the E24 series, of course.
It's definitely one or the other.

 

[Avo Mk8]

I am not convinced that the LED is presently running at 605mA. The Osram LEDset guide gives the resistor value as:
Rset [Ω] = (5 V/Iout [A]) x 1000
For 605mA that would be 8.3kΩ and although I can't see the colours on that resistor clearly enough to say what the value is, it doesn't look like 8.2 kΩ. The band that Brian sees as green, I see as blue, which would make it 16kΩ leading to a lamp current of 310mA, i.e. it might be significanly underrun (which could be a factor in the LEDs all outlasting the drivers.) I would want to double-check that before choosing an alternative driver.

Thank you Lucien for the cautionary words.

The formula you use above is for Osram "Gen 2" devices.
But the OP's part number I think indicates a Gen 1 device according to the Osram bumf?
See below - I'm not clear if this changes anything or not - your thoughts would be appreciated please.

 

[Lucien Nunes]

Good spot, I think you're right and I've edited the above post. Can we discover the relationship of resistor to current for Gen. 1 drivers?

 

[Avo Mk8]

Good spot, I think you're right and I've edited the above post. Can we discover the relationship of resistor to current for Gen. 1 drivers?

I found this (description! of link in my post #7) see below:
My attempts at unravelling this from the 274uA current, (presumably from 12V) - and I really haven't understood this - suggested someting like 7V across Rset, which would be driving the lamp a bit over 400mA.



Post crossed with yours Lucien!
I thought I had worked out the source impedance of the 274uA and I had a potential divider of that and Rset which led to a voltage across Rset that I mention above.
Clearly something wrong with that!! Yes - it's a constant current source DUH! Prefer your version.

 

[Lucien Nunes]

Oops, post crossed with yours.

It seems the Gen1 interface sets the fraction of the rated output current, not the absolute current, in the relationship: Iout = Inom ((Vset-1)/9). Vset can be derived from an active voltage source in a remote control, optionally referenced to the driver's +12V aux supply, or can be created passively by a resistor driven by a constant 274μA bias current that flows out of the control terminal. Thus for a 16kΩ resistor:
Vset = 274μ * 16k = 4.4V
Iout = 700 * ((Vset-1)/9) = 263mA

That's an even lower fraction of the panel's rating and is starting to sound unlikely.

To set a Gen1 driver of 700mA rating to 605mA with a resistor, one would need:
Vset = 605/700 * 9 +1 = 8.8V
Rset = Vset/274μ = 32kΩ or 33kΩ as the nearest preferred value.

Perhaps we are not seeing the colours on the resistor correctly, but I can't resolve them to anything like 33kΩ