STRT-G6153 datasheet

Thread Starter

GS3

Joined Sep 21, 2007
408
I am trying to repair a switching power supply. It seems the output electrolitics were mostly bad so I have replaced them. (This is most common and an ESR meter is very helpful in diagnosing this condition.) The power supply is still not working and my next suspect is the STRT-G6153 IC which seems to include a switching element plus some control circuitry. I am trying to find a datasheet for this IC but no luck so far. Can anyone please help? A schematic of some power supply using it would also be useful. Thanks.
 

Thread Starter

GS3

Joined Sep 21, 2007
408
WTF happened to that attachment? I uploaded a perfect quality PNG with a size of 1.5 KB and it was automatically converted to a crappy JPG which is ten times the size.
 

Dave

Joined Nov 17, 2003
6,969
WTF happened to that attachment? I uploaded a perfect quality PNG with a size of 1.5 KB and it was automatically converted to a crappy JPG which is ten times the size.
That shouldn't have happened - it shouldn't have even defaulted to another format. I will bring to your attention that you can upload larger JPG files than PNG files although by the looks of this is shouldn't be a problem.

Can I ask you try and upload the attachment again? If the problem persists can you let me have a copy of the attachment and I can investigate what the problem is. Thanks.

Dave
 

Thread Starter

GS3

Joined Sep 21, 2007
408
I will bring to your attention that you can upload larger JPG files than PNG files although by the looks of this is shouldn't be a problem.
The window I get says both PNG and JPG (and GIF and TXT) formats are limited to 19.5 KB and 620 x 280 pixels but I notice JPGs posted which are larger than that so I guess the info is not correct.
That shouldn't have happened - it shouldn't have even defaulted to another format.
I think it not only converted it to JPG but also reduced the size in pixels somewhat, not much. I wonder if it was that the pixel size was larger and it reduced it automatically, changing format along the way. I no longer have the original file I uploaded so I am not sure of the pixel size.

OK now I am uploading a PNG, 320 x 270 pixels, 1582 bytes. Let's see what happens... (Edit: I notice it posted correctly)

BTW, 620 x 280 pixels is rather limited for anything but the simplest schematic. It seems rather unreasonable when one can just ZIP the file and post up to 2 MB. It would also seem better if the graphic actually showed in the post rather than having to download it.

Also, JPG is a lousy format for schematics as it is not intended for such graphics. PNG is far superior in every respect.
 

Attachments

Thread Starter

GS3

Joined Sep 21, 2007
408
I am still hoping to find a STRT-G6153 replacement IC but, in case I cannot find one, I believe I have found a possible replacement IC in Fairchild's FSDM1265RB which is quite similra but would require certain modifications in the circuit.

There are two main modifications to be made. Let us compare.

Pin 1 is DRAIN in both and needs no changes.

Pin 2 in STRT-G6153 goes to the current sensing resistor while FSDM1265RB has this resistor built internally and pin 2 is GND. It is easy enough to short the external resistor and put pin 2 to gnd.

Pin 3 in STRT-G6153 is GND while pin 3 in FSDM1265RB is the supply voltage (pin 5 in STRT-G6153)

Pin 4 is Feedback in both and can be connected directly.

Pin 5 in STRT-G6153 is Vcc while pin 5 of FSDM1265RB is not connected.

Pin 6 of FSDM1265RB is the startup voltage.

In summary, both have 5 active pins but FSDM1265RB has a total of 6 and one is not connected. Ignoring pin numbers and just attending to their function we have one which has disappeared which is the external current sense resistor and a new one which has appeared as the one supply pin in STRT-G6153 has split into two in the FSDM1265RB which are startup (pin 6) and Vcc (pin 3).

The FSDM1265RB datasheet should clarify any doubts.

I am including a generic schematic of how I would convert the circuit from one to the other. Please note that I have not tried this yet so it is merely a tentative idea which I believe might work if I have not overlooked anything important. Also please note that this is a generic circuit and each individual circuit might have its own considerations.

I have compressed the PNG graphic using ZIP and I want to say this would not generally be a good idea at all but it seems the software here messes with PNG graphics converting them to JPG (which is worse than terrible) so I have Zipped it to prevent that from happening. Another option would have been PDF but ZIP is better because it allows you to directly recover the graphic as it originally was.
 

Attachments

Thread Starter

GS3

Joined Sep 21, 2007
408
I have one big doubt about using the FSDM1265RB.

The original STRT-G6153 uses an external resistor to sense the current through the FET and inductor and by selecting the value of this resistor the designer can set any limit on this current. I believe the original circuit has a 0.5 ohm resistor.

Whereas the FSDM1265RB has the resistor built in and cannot be adjusted. The datasheet says the circuit is designed to limit the inductor current to 3.4 A typical, 3.8 max.

BUT, I have no idea what the max current limit is in the original circuit. (At 3.6 A the voltage drop on the resistor would be 1.8 V but I have no idea how to evaluate that.)

I have no idea of what the frequency of the original circuit might be.

At this point, if I cannot find an original IC replacement, I may try the FSDM1265RB with plenty of protections and limitations and see how it works.

I am guessing there are probably out there other ICs which are functionally equivalent to the STRT-G6153 but I just can't find any.
 

Thread Starter

GS3

Joined Sep 21, 2007
408
Well, I am still working on this. I cannot find the original IC so it looks like I'll be modifying the circuit and trying to adapt a different control IC, possibly one of the FA1384X family.

I am attaching the schematic as far as I have deduced it.
 

Attachments

Thread Starter

GS3

Joined Sep 21, 2007
408
Well, I am still trying to get this project done but I still cannot find the IC. I have put a MOSFET in place and gently switched it and everything seems to work. I just need either the original IC or a suitable replacement. It seems the KA1L0380 is very similar and the circuit could be adapted to use it but I can't find that one either.
 

Thread Starter

GS3

Joined Sep 21, 2007
408
After calling many local small places I found a place where they said they had the KA5L0380R. I went over and bought it quite inexpensively and when I was already on my way out chatting about the repair the guy said, "hmm, STRT-G6153? let me check..." and he found he had one in stock which for some reason did not show up in the computer. So, for under US$2 (and many hours searching) I finally found the part. I kept the KA5L0380R because it was not worth the trouble of returning it. I don't know if I'll find a use for it. Maybe for some design or experiment.

So, I got home and could not wait. I installed the replacement STRT-G6153 and fired up the SMPS with many protections as the last thing I wanted to do was blow up the replacement IC. Everything seems OK. It is switching at a steady 70 KHz with input voltage between 150 V and 300 V. The IC Vcc is steady at 14 V. The circuit seems to be working in CCM. This is just after a very quick look. I am not done testing yet so all this is just preliminary.
 
Top