LM5160A: 5160A diode (DFL1100-7) > 100ºC

Aaron Lee21

Part Number: LM5160A

Hi,

We use LM5160A for flybuck. The input is 9~36VDC and output is 24V. There is a problem is that when the input over 30V, the diode D3 temperature is very high.

Do you have any recommend?

Output: 24V / 35mA

Best Regards,

Aaron

over 6 years ago

0 Robert Blattner over 6 years ago

TI__Expert 6245 points

Hello Aaron,

A quick calculation shows that the diode will start to have breakdown with input voltage around 24 V. The calculation is:

Vsw/Vout = (Vin – Vout) / -Vout = (24-(-8))/-(-8) = 4x
Vout2*(Vsw/Vout) = 24*4 ~ 100 V

Since it is hard to find a Schottky with breakdown above 100 V, you have 2 options:

1) Stack 2 diodes of the type that you are already using.
2) Use a Carbide diode. Infineon makes these.

Regards, Robert