Hello Keshab,
Evidently, there are more issues than just the diode ones that I mentioned.
Please refer to this debug guide to help you get further along with the debug:
Troubleshooting TI PSR Controllers slua783.pdf
Perhaps something in this procedure…
Other Parts Discussed in Thread: UCC28600 Hi everyone,
We are trying to build a Quasi-Resonant Flyback converter with the UCC28600 .
Input: 80V to 450V DC
Two outputs: 12V @ 0.83A (10W)
At first we tried providing 80V at the input and found…
Hello,
Not sure why connecting the HV9961 to the output or your flyback would cause regulation issues. You might want to study VDD, Aux and CS to see if you are turning off do to a fault.
The attached application note explains how the fault sensing…
Hello,
The Webench tool will give you a working schematic and instructions no how to build the transformer. However, these primary side regulated flyback converters are susceptible to aux winding noise.
I would study VDD, CS, VSENSE and Vout to…
Hello,
If the UCC28704 is shutting down you noise immunity test maybe accidently triggering and over voltage protection (OVP) fault, and input under voltage (UVLO) fault or an over current fault.
I have attached a draft of an application note that…
Other Parts Discussed in Thread: UCC28700EVM-068 Hi,
Now I'm promoting the UCC2870x that is controller with primary-side regulation to our customer. Then they are asking about accuracy of voltage regulation. In UCC28700EVM-068, it state min/max of Vout…
Hello,
Slide 10 you might want to look more into the first time VDD reaches VDDon. There are most likely three gate driver and CS pulses you are not seeing doing to scope resolution. The device may not be starting up because input under voltage lockout…
Hi Amr,
here attached a application note which shows how to design the RC clamp in section 9.
e2e.ti.com/.../0844.Clean-PSR-Sensing-App-Note-10-5-20B.pdf
Thanks
Hello,
If your output is dropping out from 12 V to 4 to 5V you may have a fault or your transformer turns ratio is not correct.
I have attached and application note that discusses how PSR fault sensing works and the most common issues that arise…
Hello,
If VDD is cycling most likely the device is entering a fault. I have attached and application note that discusses PSR fault sensing most common issues and how to resolve. It also explains how PSR sensing works. This information should help…
