Not so many but I have several time that the prototype made from TI ref design. It's not running (or burned, or nothing in secondary side) at first time. Some reason is Transformer, feedback, layout... So, I took time to read book and datasheet (DS) carefully.

First, the DS show that your VDD need in range:

Second, R7, you need ~200k Ohm (according calculation), and you should use 2x 100kOhm (not 1 resistor 200k)

Third, be careful with transformer pol. If , for example bias winding is wrong, simply rotate the dioe 180*C

Not so many but I have several time that the prototype made from TI ref design. It's not running (or burned, or nothing in secondary side) at first time. Some reason is Transformer, feedback, layout... So, I took time to read book and datasheet (DS) carefully.

First, the DS show that your VDD need in range:

Second, R7, you need ~200k Ohm (according calculation), and you should use 2x 100kOhm (not 1 resistor 200k)

Third, be careful with transformer pol. If , for example bias winding is wrong, simply rotate the dioe 180*C

Forth: Check the pulse on Drv pin, check Voltage on CS pin Also need check voltage con SD pin and you should place a 470k Ohm res to GND IN