What is wrong in this buck converter spice simulation?

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shankey_1919

Joined Feb 9, 2010
6
Hello everyone. I am trying to simulate the operation of a dc to dc converter on LTSpice. Input is 18V DC, o/p is 9V DC with 3 A current... The output seems to be related to the duty cycle as the o/p voltage are duty cycle =1 is almost twice the o/p voltage at duty cycle = 0.5. But why does the output have very low voltage?
 

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Thread Starter

shankey_1919

Joined Feb 9, 2010
6
Hello guys.. I just realised the mistake I made. I should have applied the V2 pulse between the gate and source. But even applying the above causes a similar output to the attachment in the above post if the mosfet used is the default one in LTSPICE. Using any other mosfet with low Rds(on) seems to solve the issue. Thanks...

(I have attached the new simulation results)
 

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