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Electronics => Repair => Topic started by: maselectron on March 14, 2020, 12:29:06 am

Title: LED Driver IC 51LP
Post by: maselectron on March 14, 2020, 12:29:06 am

Hi All,

This is my 1st post and I apologize if it is in a wrong section. Please feel free to delete or move to the right section.

I have a 9W LED bulb and it has a transistor like TO92 IC marked as 51LP and beneath it marking F48, which is blown up.
I want to repair this and coudln't find the part nor a datasheet to see if possible to find a substitue.

Attached are few shots.

Thanks

Title: Re: LED Driver IC 51LP
Post by: shakalnokturn on March 14, 2020, 01:26:01 am

Hello,

Check here:
https://electronics.stackexchange.com/questions/414791/troubleshooting-defective-led-bulbs

https://datasheet.lcsc.com/szlcsc/1907311706_KIWI-KP1051FPA_C261502.pdf
(You'll have to run it through a translator yourself  ;))

Title: Re: LED Driver IC 51LP
Post by: JFJ on March 14, 2020, 02:08:51 am

There's a link to a one page datasheet, in English, on the manufacture's website:
http://www.kiwiinst.com/product_detail.aspx?k1=2&k2=6&k3=24&id=132 (http://www.kiwiinst.com/product_detail.aspx?k1=2&k2=6&k3=24&id=132)

There appears to be a small number for sale here:
https://www.olx.ro/oferta/kp1051-51lp-integrat-ic-tranzistor-mosfet-quasi-resonant-buck-IDcS5Ld.html#55cc21ad46 (https://www.olx.ro/oferta/kp1051-51lp-integrat-ic-tranzistor-mosfet-quasi-resonant-buck-IDcS5Ld.html#55cc21ad46)

Title: Re: LED Driver IC 51LP
Post by: TheMG on March 14, 2020, 02:33:19 am

Have you first checked that the LEDs are still ok? Quite often when the driver goes *bang* like that, the LEDs are smoked too. The current sense resistors (RS3, RS2) are burnt which likely means a lot more than the normal amount of current flowed, and that current path could have been through the LEDs.

Assuming the LEDs are ok, you'll have to calculate from the datasheet info and reverse-engineering of the circuit, what the proper value for RS3 and RS2 are supposed to be, since they don't appear to be readable anymore.

Obviously, electrolytic capacitor is shot too. Possibly other components as well. Test everything.

Title: Re: LED Driver IC 51LP
Post by: rvalente on March 14, 2020, 12:39:32 pm

THe 51LP TO92 package is not a transistor but a LED controller in "transistor" package, I probably won't be able to buy it in small quantities or in the local market.

So, the lamp is dead for good. For educational purposes its fun to investigate and try to repair, but usually, for the price point of these things, its nonsense to fix them