[SOLVED] DC level in current transformer

Hello
I am designing a DC / DC 150V input source and a 250V output, at a power of 1200W, and fullbridge topolofy. At the moment I do not have a 150v DC source, therefore using the same hardware calculated for a 150V input and a 250V output, I am using a 30Vdc input source and a 65V output, obviously limiting the power to 150W. All this I do to test the operation of the UCC28950 controller.
To sense the current, I am developing a current sensor with ferrite toroids that I find in the local market. The toroids used are of T38 material of epcos and the other has no specifications. I give 100 turns to both and I get approximately Lm = 30mH, in both cases.
The problem is the same in both transformers, because a DC level appears in the output signal (see image). This DC level prevents me from controlling the circuit, because the more the load increases, the DC level increases, reaching the 2V level of the pin cs too fast.
I'm implementing the circuit found in the UCC28950 data sheet, and the circuit on the PMP6712 ​​board is also implemented, but the result is the same in both cases. I suspect that the transformer can not be reset.
What should be the selection criterion for the core? Or is there a problem with the circuit that I have implemented (see image)?

Thanks.

what is the switching frequency you are using??

often best to use a diode and zener to reset, you are sure of reset.
I will send you info soon.
I am on BTopenzone internet network and it is very slow and i will send you the zip file on CSTs soon.

Hello everyone.
I have been able to solve my problem. The cores I was using are not reset because of their remanence. I choose to use a 125 ui sendust core, and the core is reset without problem. Then buy the current sensor B82801C2245A200, and it is also reset without problem.

That should not matter what core. To reset a current sense transformer, you just have to make sure that "volt.seconds off" is at least equal to "volt.seconds on" for the secondary coil.

treez said:

That should not matter what core. To reset a current sense transformer, you just have to make sure that "volt.seconds off" is at least equal to "volt.seconds on" for the secondary coil.

Click to expand...

It is assumed that R23 serves to reset the core, and the greater the resistance, the reset time will be shorter, with the consequence that the diode will have a higher inverse voltage. I put very large values of this resistance, and even so the offset error is presented. I agree with you that any core in theory should work, but I'm not sure because the cores that I use do not reestablish, with the circuit that I implemented. I suppose there must be ways to reset the core actively, but for price and space I am not willing to use them.
I simulate core 3c94 and t38, and I can observe the same response I got in the actual circuit.

It can be possibly derived from the post #1 waveforms, but you didn't yet clearly tell the parameters specifying your problem. Under circumstances, the core is already saturated by a single pulse, "reset" won't help in this case.