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Identify this LED Buck Driver IC?
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wholder:
I've reversed engineered the schematic (see attached) for a laser diode driver circuit used in a laser engraver that I think is using an LED Buck driver as the main IC.  However, as usual, the 8 pin SOIC IC contains no visible markings. So, I'm hoping someone can help me identify a probable part number for the IC based on the schematic.  Any have any ideas?

Wayne
Jannehrl:
I assume that the 220nF capacitor is a inductor? Im not so familiar with us symbols so sorry if im mistaken.

Anyway, it doesnt look like anything special, there are many many LED drivers that have the same function
with different configurations to enhance certain characteristics or to add features.

Maybe i can help you by giving an example:

PAM2863ECR

AP8801SG-13   

NCL30160DR2G
wholder:
> I assume that the 220nF capacitor is a inductor?

Yes, sorry, the inductor should have been labelled 220uH, not 220nF.

> there are many many LED drivers that have the same function
> with different configurations to enhance certain characteristics or to add features.

I'm trying to identify a device that matches the pinout to see if it can help narrow down the specs for the device.   So far, the Diodes Inc devices, such as the AP8801SG-13 and the PAM2863ECR are the closest, but the pins don't match up.

This IC came from a laser engraver that is advertised as putting out 3500mW.  I'm trying to determine if this claim is even close to reality by analyzing the circuit.  I'm also trying to understand how the PWM input works and the function of the 900nF cap on pin 6.

Wayne

Jannehrl:
I highlighted the PWM part with red of the NCL30160. I also made a small diagram as how the Signal probably look like. If your PWM signal is low, the LED current is blocked by the FET.
If your PWM signal is high, the regulator aplies a PWM with a higher Frequency in order to control the LED current by the coil. The dutycycle is most probably not 50/50 as i have drawn it.

The Wattage of 3.5W should be no problem for the Driver itself. The NCL30160 has a max driving current of 1.5A and with an assumed diode forward voltage of 3.3V, the resulting power is approximately 5W.
But that doesnt mean that the LED can handle it.

The 900nF capacitor might also be 1uF if you look at the tolerance of normal capacitors and the accuracy of capacitance measurement.
If this is the case, this is just another decoupling capacitor with no special function.
wholder:
I use DigiKey's online editor, Scheme-it:

  https://www.digikey.com/schemeit/project/

Wayne
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