TMDXIDDK379D: schematic files for the M2/M8 modules

Hi,

Did you make any changes to the schematic / components of the design shared in the previous thread? Did you follow the PCB layout file?

https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/1242089/tmdxiddk379d-schematic-files-for-the-m2-m8-modules

Best,

Kevin

Dear kevin, Please click the following link to see the shared schematic and pcb files .

https://drive.google.com/drive/folders/1UL-cn1SSCg1CT0WaHNw5tsVJA6aAV5A_?usp=sharing

I followed exactly the same as shown in the schematic and PCB you have given to me. Only one component FQD3N60 is currently unavailable, so we used STD3NK60ZT4 as a substitute. The voltages at the pins of UCC28600 is also showing strange values and its fluctuating  as written below 

1. SS = 130-160mV
2. FB = 1-3V
3. CS = 8.1mV
4. GND
5. OUT = 52mV
6. VDD = 11-12V
7. OVP = 60-140mV
8. STATUS = 11-12V

Hi,

Please allow us to look into the provided files and info further to provide suggestions. My colleague who's more familiar with designing these power modules is out this week, so I may not have good suggestions to share until he's back and we discuss.

Best,

Kevin

Dear Kevin, 

We are awaiting your feedback. We need to arrive at a solution as soon as possible. Can we review any parameters before your colleague contacts you?

Hello,

It seems from VDD reading that device is going in undervoltage lockout. Try increasing increase the bulk capacitor C6 on VDD to somewhere from 82uF to 100uF or maybe larger and make sure VDD pin reading are in range specified in datasheet (nominal around 13V). It looks like there isn't enough energy for the bias windings to take over because there isn't enough charge holdup at startup. I would suggest try crosscheck assembled overvoltage protection resistor as per bom.

If these suggestin doesn't work, please verify your design calculations using WebBench Power Designer tool. For example, here is the tool link for the IC you are using. Change the parameter as per power supply specification and it will calculate component values for you - https://webench.ti.com/power-designer/switching-regulator/customize/11?VinMin=85&VinMax=265&O1V=15&O1I=4.33&base_pn=UCC28600&AppType=AC&Flavor=None&op_TA=30&origin=pf_panel&lang_chosen=en-US&optfactor=3&isolated=Y&Topology=Flyback&source=AC&line_fsw=60

Sumit

Hi Sumit,  We have tried with 100uf for C6 Nothing changed from previous condition. Any way we will try to get 400V supply for giving as input . hoping that it will give the out put as per the design.

Hi,  We have assembled the input board M1  for 400V but its also giving 310V at the (with bulk capacitor) outputs. So connecting this to M3 board   not solved my issue . Can you say the range of input voltage the board expects to produce the 15v/5v output?. Is it 310V is not sufficient for that?. I think fixing the VDD will solve the issue. The VDD is still in under voltage lock out mode. Its not a proper way to go for another design without understanding the fault of the existing design , So kindly guide us to the solution.  

Hi Biju,

Did you assemble multiple board of this design? Is the same issue occuring on other boards as well? This is to cross check if any component assembly error, especillay resistor and cap are vaule wrong or swapped. 

Sumit

The cross checking process is already completed many times. we  have assembled two boards and both are giving same result.

Hi Biju,

Could you please share start-up sequence along oscilloscope waveforms of VDD, STATUS and FB pin from which we can see whats happening?

Regards,

Sumit

Dear Sumit,

Please download the TINA simulation model from below link. 

www.ti.com/.../slum608

Can we focus on this Simulation model first and if this operates fine ,We will get a reference model to replicate  . Can you simulate and  modify this model to get a 15 v output? I am not getting even its default voltage 3.3v ?

Thanks for your sharing model. I will take a look into it and will get back to you.

Awaiting your response

Biju,

Which transformer (part number) are you using in this? it looks like we are using custom transformer in this one. Schematic you shared doesn't have part number.

Sumit

We have not changed the transformer , used the default one T1 (GA3544-BL.) shown in  the schematic -

Please see the link  https://mou.sr/3N6vEKP