I am using LT8315 as a non-isolated buck converter. The input range is 200-400V, the output is 12V 100mA (max)
LTspice simulation shows ok in the input range 30V-400V with static load 120mA.
But actually it works from 30V up to 200V and the output is 10.2-11.8V depends on the input voltage and not strongly regulated. The frequency changes from 16kHz at low input voltage up to 19kHz at 200V. If the input voltage is close to 200V or higher some kind of the protection observed and the output is drop and pulses.Above results I have got when the LT8315 only was tested and everything else was disconnected and 100R load was used in parallel with D403.Could someone say me pls where i am wrong?Sch attached
C440 value is incorrect. 10nF or less is suggested.
Tks for your reply.
Have replaced the C440 to 10n, nothing changed
Below are some screenshots captured at the Source pin (pin18):
first is at 100V input, next is at 200V and signal became not periodic, last one is at 250V when converter is not work and the audible noise is hearing
I'd check the layout. The layout file of the evaluation board can be found in the below link.
I have found that in the BOM of the DC2478A was changed type of the D3 to extremely fast one C3D1P7060Q.
What are the requirements for this diode?
Is diode S5JC-13-F (D402) I used ok for this purpose?
And can I post a Gerber files for your review the layout?
Can you tell us what is Estimate Annual Usage and is there a way you can contact for ADI support in your local area?