Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

XMC™ Forum Discussions

Jeddison
Level 1
Level 1
First solution authored First reply posted First question asked

Hi,

Looking at the circuit diagram of the XMC Digital Power Explorer Power Board from Infineon, I find that there are 2 Inductors are used L1 and L3 from Würth. This circuit is a synchronous buck converter using IRS2011SPBF to drive the 2 MOSFETs as show in the attached file.

Why would the designer use 2 inductors in this circuit?

Would it be possible to use only one inductor?

What is the function of the resistor in parallel with L3?

Thank you in advance

Jeddison

0 Likes
1 Solution
Andrew
Level 2
Level 2
5 replies posted 5 sign-ins First solution authored

Hi Jeddison,

Note: I am not familiar with the XMC Digital Power Explorer Power Board.

L3 is only 470 nH, which is a factor 50x smaller than the main power inductor L1 at 22 uH. L3 is thus not used for power conversion, but rather for filtering out high-frequency switching noise. R127's function is to make this filter dissipative, thereby lowering the Q-factor / preventing resonance.

View solution in original post

2 Replies
Andrew
Level 2
Level 2
5 replies posted 5 sign-ins First solution authored

Hi Jeddison,

Note: I am not familiar with the XMC Digital Power Explorer Power Board.

L3 is only 470 nH, which is a factor 50x smaller than the main power inductor L1 at 22 uH. L3 is thus not used for power conversion, but rather for filtering out high-frequency switching noise. R127's function is to make this filter dissipative, thereby lowering the Q-factor / preventing resonance.

Hi Andrew,

thank you for the explanation, the time and effort you put into it.

Do you have any references where I can look into this and similar subjects.

Best regards,

Jeddison

0 Likes