LM5122: Negative Buck converter design critique

martin_sanco

Part Number: LM5122

Dear engineers,

I would like to ask you to critique my design of the negative buck.

As you can see I chose LM5122 which can stand only 65V so I made a simple regulator for the controller.

Another thing is the voltage translation which is implemented by the modified current mirror built with dual PNP transistors.

If you can see any problem which may be related to my design please let me know.

Many thanks.

0 martin_sanco over 5 years ago

I found mistakes in the output section.

Please find the updated file:1134.zaporna cast v1.pdf

0 Youhao Xi over 5 years ago in reply to martin_sanco

Hi Martin,

Thank you for designing with the LM5122. The schematic basically looks okay.

The input capacitors Cin1 through Cin4 should be placed directly across -VIN and GND rails.
You should reserve the R-C-R network for the current sense pins.
For the paralleled FETs, you should add 1 Ohm resistor to each gate.
You may consider to reserve an RC snubber across SW node and -VIN node.

Good luck in your project.

Youhao Xi, Applications Engineering

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