Power Management +24VDC to fixed +5 VDC

Hi F.Kamm!

It suggest TPS62932.

https://www.ti.com/lit/ds/symlink/tps62933.pdf?ts=1650365946851&ref_url=https%253A%252F%252Fwww.ti.com%252Fsitesearch%252Fen-us%252Fdocs%252Funiversalsearch.tsp%253FlangPref%253Den-US%2526searchTerm%253DTPS62933%2526nr%253D44

BSR-MV

Shuai

Hi,
how did you choose this one?
Does it have a minimum load current?
Can you maybe tell me the differences to the L7983 with fixed +5V...

Thank you,

Fabian

Hi

You can refer the datasheet. It can cover what you need.

And this is BSR-MV BU, L7983 isn't our product.

Shuai

Hi,
oh sorry, my mistake.
Okay. Thank you very much.
But i have to use external resistors, is there a fixed one too?
And if i understood the Power Dissipation right, then i will calculate the junction temperature
with Eq.24 in the Datasheet to 32,6°C? Is that realistic?
V_out = 5V, I_out = 0,1 and from the figures efficiency of 88%.

What do you mean with BSR-MV BU?

Thank you!
 

Hi 

Which resistor do you mean?

Shuai

To define the output voltage.

greetings

Fabian

...

Sorry i dont get what you're trying to tell me.
The one you showed me, needs external resistors R_FBB und R_FBT to set the output voltage. (Figure 8-2 in the Datasheet)
I dont find hints that there are options for integrated setting resistors.

My question is, if there is a converter with a fixed output of +5V DC that suits my application.

Or why is there a big advantage to use external resistors for setting the output voltage than using a converter with a fixed output voltage, like the TL2575?

Hi Fabian!

I understand your meaning this time！

Actually， I didn't see any parts with a 5V reference. 

Answer you second question: with a reference of 0.8V, customer can set the varied output voltage by divider for  different application condition.

Shuai

Hi Shuai,
okay, no problem. Thank you for your answers. first time designing a pcb and actually i'm little insecure, how
the buck converter will affect the result of the INA240. Thats why i tried to use a fixed buck converter ,
so i dont get any noise and additional errors by the external resistors.

Thank you,
Fabian

Hi

The fixed converter you mentioned is also use a resistor divider(internal).

For a switch regulator, the noise is inevitable, both the TL2575 and TPS62933 . But our product has try our best to decrease it. If your application need a vary low noise requirement, you can use a LDO.

Shuai

Do you think it is better, to take two LDOs in series, so that the voltage drop for one isn't that big?

You can use a buck achieve 24V to a voltage a little higher than 5V. Then use a LDO regulate a fixed 5V.

Shuai

Thank you very much.
Last question: Do i have to expect noise or any frequency ratios after the LDO because of the switch regulator?
Or will anything be filtered?

Thank you.

Fabian