Quoting John Coppens <john@jcoppens.com>:


The chip is made in China by Bright Power (Shanghai).

https://i.imgur.com/PC2pGzD.png


I doubt there's much point in them exporting the chips to the West.
China and SE Asia is pretty much the world market. 1 reel is 15,000 pieces.


--sp



> Hello all.
>
> I've been really surprised at the variations of the circuitry inside
> LED bulb replacements. A while ago, I bought a couple of bulbs ('Great
> Value'-brand, a local Walmart product), which started showing failing
> after just a couple of weeks. Opening them up showed that they were
> fed by just a (linear) series regulator. So much for green energy.
>
> Now I acquired a couple of OSRAM bulbs, and opened one up just to
> investigate. It did have a switching current regulator, but it used
> a 4-pin chip for which I could not find any data. In fact, I didn't
> find _any_ 4-pin current regulator IC.
>
> I've attached the circuit. I suspect the 1.8 Ohm resistor to be the
> current-determining component. Strange is the (I suspect) transformer
> which is actually across the LEDs (I'm not positive about it's
> internal connections. I measure 10 Ohm across two pins, 14k across
> two other pins, but without unsoldering). 12 LEDs (I suspect triplets)
> are connected between + and -.
>
> Does anyone have an idea which IC this could be? It's marked 9938F
> and S1C01X. No logo as far as I can detect.
>
>



--=20
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