TPS54561: TPS54561

Arjun P bhaskar

Part Number: TPS54561

Hi TI,

I have designed a circuit to step down the input voltage of 48V to 24V with expecting an output current of 3.1A.Could you please verify the circuit to know any issues are there in the circuit. I also have faced an issue in the previous circuit while designing a regulator to step down input voltage of 48V TO 24 using a AP66300FVBW-13 (Diodes Incorporated). The issue was occurred when hot swapped the input power connector frequently.so my concern is whether i have to add any protective schemes in the current circuit.

over 1 year ago

+1 Ridge Lahti over 1 year ago

TI__Mastermind 22260 points

Hello,

Overall the schematic looks OK. The inductor is larger than typical. I calculate 19uH for this application. When selecting an inductor, it is important to calculate the value using the full load capability of the device even if the application will use less than what the device is capable of.

What issue specifically did you encounter and what do you mean by "hot swapped input power" ?

Best regards,

Ridge

0 Arjun P bhaskar over 1 year ago in reply to Ridge Lahti

Prodigy 100 points

ACE Scanner_2024_03_25.pdf

In this attached PDF i have calculated the inductance as you mentioned. But it will cause a 40% of the ripple.is it high with respect to the load current. and what is the reason for selecting full load current for linductance calaulation?

Hot swapping means insertion and removal of the connector one or twice suddenly to the circur

0 Arjun P bhaskar over 1 year ago in reply to Ridge Lahti

Prodigy 100 points

Is the output capacitance is ok with respect to stability?

0 Arjun P bhaskar over 1 year ago in reply to Ridge Lahti

Prodigy 100 points

Why we have to choose 10.2K as Rbot

0 Arjun P bhaskar over 1 year ago in reply to Ridge Lahti

Prodigy 100 points

For a higher voltage indication is this a good method of using LED as indicator directly as used in the circut

+1 Ridge Lahti over 1 year ago in reply to Arjun P bhaskar

TI__Mastermind 22260 points

Hello,

Please see my answers to your questions listed below:

With regard to the inductor, 20% to 40% ripple at the full load of the device is typical for a buck converter. The inductance should be calculated with that ripple current range in mind. When choosing and inductor, it is important to use the full load current of the device for stability purposes. The value calculated at the maximum load will work for lighter loads as well.

The device can withstand up to a 60V transient. You may want to clamp the input if you think your transient could go higher than 60V

The output capacitance looks fine.

The resistance value is chosen to meet the requirements outlined in Section 8.2.1.2.10 of the datasheet. It is possible to use other combinations as long as you meet the requirements specified in the datasheet.

I can't comment on your LED and how it may relate to your system. It should not cause an issue with the buck converter.

Best regards,

Ridge

0 Arjun P bhaskar over 1 year ago

Prodigy 100 points

Is there any issue in placing a test point to the feedback pin

0 Arjun P bhaskar over 1 year ago in reply to Arjun P bhaskar

Prodigy 100 points

in the routing tp is in the path of the fb . is there any issue?

+1 Ridge Lahti over 1 year ago in reply to Arjun P bhaskar

TI__Mastermind 22260 points

Hello,

If it is a surface test point it should be OK (solder mask is removed on the trace). It is not recommended to have a through-hole test point on the FB pin.

Best regards,

Ridge

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TPS54561: TPS54561