Author Topic: Chip identification? Flyback controller that uses BJT?  (Read 196 times)

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Offline mikedoubleu

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Chip identification? Flyback controller that uses BJT?
« on: January 11, 2020, 05:33:28 pm »
Hello all,

I'm wondering if anyone can help me identify a little 6 pin chip.  It's the controller chip for a small flyback SMPS.  I'm fairly new to these things, but it seems notable that the switching transistor is a BJT (SD13003) as opposed to a MOSFET.  I'm hoping that can help me track down the part number, but I'm having a hard time so far. 

The marking is 20F09, and also 57A on another line. 

Also, there's no feedback from the secondary here, not sure if that helps identify a category to search in...

Thanks for any help or advice!
 

Offline T3sl4co1l

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Re: Chip identification? Flyback controller that uses BJT?
« Reply #1 on: January 11, 2020, 06:14:32 pm »
TI makes one, https://www.ti.com/lit/ds/symlink/ucc28722.pdf but I'd bet you have a Chinese version.

Tim
Seven Transistor Labs, LLC
Electronic design, from concept to prototype.
Bringing a project to life?  Send me a message!
 

Offline mikedoubleu

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Re: Chip identification? Flyback controller that uses BJT?
« Reply #2 on: January 11, 2020, 06:36:23 pm »
Ah shoot, close but no cigar.  Pinout a bit different.

Thanks for that though, I'll keep digging. 
 

Offline mikedoubleu

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  • Country: ca
Re: Chip identification? Flyback controller that uses BJT?
« Reply #3 on: January 11, 2020, 06:52:29 pm »
SOLVED!  It is OB2520. 
 


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