Dear TI Team,
I am designing the UCC28700-Q1 and have a problem during the test to request help.
1. The waveform of VDD is measured as shown below.
It seems to swing from 21V to 7V with protection.
Debugging contents are as follows.
1. CS : 1.7K Ohm / 1.5Ohm to 1.2/1.0/ 0.7Ohm Change Test
2. VS : 75K Ohm / 41KOhm to 39K/37K/32KOhm Change Test
3. VDD Cap : 2.2uF to 330nF/470nF/1uF/10uF/22uF/47uF/100uF Change Test
4. Transformer : The transformer ratio is 6: 1: 1: 1, and the value of the inductance corresponding to each turn ratio is 550: 15.8: 15.9: 19.8 uH.
Turns : W1 54t / W2 9t / W3 9t / W4 10t --> W2 15t Change Test
I have tested the above but I can not improve it. Please check if there are any more areas to check.
Schematic
Thanks.
