TNY276 and +-15VDC

I have a questions May be it does not have sense.  Di you enter negative output and positive output?

Can you place post the PI expert file.  It may happening a nono in the software cause this output.  

I cant see any option in the software that allows me to PUT -15V or negative

Regards 

Ok,

I found it was my mistake when I entered the values, there is a button (+) to change, however

Now I have the right schematic.

I wonded my EE19 as described in the design 87Turns, and 14 Turns for secondary.

I am getting 14.26 VDC, when I load the SMPS with 270R resistor, the SMPS turns off after 40 seconds, and TNY chip heats up to 50C.

Inductance of primary is 893 uH

Any help? 

You are loading with 270R resisto....Are you loading  one output only?  or both outputs with 270 Ohms on each output?

Hello 

Problem solved, I swapped the primary windings (start point), now I can load 100R without problem to the +15VDC line

Now new problem appeared. See attached please

the  -15VDC  line is not stable, in idle its increasing for no reason, also when loading it it drops to 5V, also when loading the +15Vdc   line the   -15VDC drops.

All tests GND refrence 

Any suggetions?

Regards 

What do you mean """the   -15VDC  line is not stable,....."   Do you mean +15VOUT  is regulated but -15VOUT is not?  

If we assume the power supply does not have any additional problem then it means you are having cross regulation issues.  

When you wounded your transformer you should had done as follow.  Wound the two secondaries  at the same time in parallel. In other words Start winding bot wires at the same time and finished them at the same time.  Then connect each winding to his respective legs.  Of course you should pay attention for the wires to be properly in phase. 

Not a very good regulation is an intrinsic situation for multiple output flyback-design.   Depending on your load and regulation needs to may need to regulate your outputs using TL 431 instead of zener diode. 

Hi 

I am refering again to the attached schematic.

I wonded the transformer as you have mentioed, same problem.

the +15VDC output is working perfect, with load and without load (+15VDC Stable)

the -15VDC in IDLE (NO LOAD) increases for no reason, and reaches 23VDC, if I load this (-15VDC) output it drops to 10VDC. and the (+15VDC) output is stable +15vdc.

I dont know whats going on really.

Any suggestions? 

   I sugest you you try to use TL431 isntead of zener for your regulator circuit.  

Sure thing.

I will try the TL431 instead of Zener diode.

But, In this kind of circuits, regulating the +15V rail, will also regulate the -15V rail?  whule the -15V rail is not sending any feedback like the +15V rail?

Regards 

I started to lose intrest into this chip and this design.

i really cant get it how the circuit will regulate the -15VDC line without sending any feedback to the chip.

I have just finished testing the TL431 circuit as attachesd, SAME PROBLEM as mentioned before.

Either PI engineers show up a solution, either telling me ITS NOT POSSIBLE.

please make a test with this circuit and dont take this issue as simple as you think

Please advice 

I am sorry 

is hard for me to find an immediate  solution when I am far from the circuit.   

Yes but you could show evidence of a working circuit with +-15VDC

I searched the we for days trying to find one, with no success

and its RARE use, +-15vdc

I dont understand a large firm like PI cannot provide help

I will contact Head quarters 

If you try TL431 feedback you can slip the feedback between both outputs. Every feedback can be adjusted to carry certain percentage of feedback to adjust your output depending on the variations of your load.  It may be fit your regulation requirements but still may not be enough. It depends on your output specifications.