TPS923652: Product decision + design

Fabian Hladik

Part Number: TPS923652
Other Parts Discussed in Thread: TPS922050, TPS923650

Tool/software:

At short notice, our customer has requested that our product support multiple display types, each with a different backlight configuration.

As a result, I need to quickly find a backlight driver that can support various LED backlight types.

Goal:
We want to configure the driver for different backlights by swapping only the feedback resistors.

Input Voltage Range:
20.4V to 28.8V

Backlight Requirements:

3.2V @ 60mA
6V @ 240mA
21V to 27.5V @ 40mA

I have selected the TPS923652.

Questions:

Do you think the TPS923652 is suitable for this use case?
My calculations show different inductor values are needet for each backlight. Can I use the maximum required inductance for all configurations, or do I need to reduce it depending on the display?

Thanks in advance for your help!

4 months ago

0 Lucia Gao 3 months ago

TI__Mastermind 30171 points

Dear Sir,

Pls kindly let me check and get back to you soon. Thank you!

BRs

Lucia

0 Lucia Gao 3 months ago in reply to Lucia Gao

TI__Mastermind 30171 points

Dear Sir,

Do you mean that you only want to change Rsense in below schematic for all three applications? (Other BOM keep same)

Fabian Hladik said:
We want to configure the driver for different backlights by swapping only the feedback resistors.

Thank you!

BRs

Lucia

0 Fabian Hladik 3 months ago in reply to Lucia Gao

Prodigy 20 points

Hello,

thank you for the reply.

If absolutely neccersairy, other passive components can be changed.

The goal is to be able to use the 3 mentioned display types with minimal hardware modification and using only one driver.

0 Lucia Gao 3 months ago in reply to Fabian Hladik

TI__Mastermind 30171 points

Hi Fabian,

Fabian Hladik said:
Input Voltage Range:
20.4V to 28.8V

Backlight Requirements:

3.2V @ 60mA

6V @ 240mA

21V to 27.5V @ 40mA

Thanks for your feedback! I would recommend TPS922050 for 3.2V@60mA and 6V@240mA and TPS923650 for 21V to 27.5V @40mA.

Thank you!

BRs

Lucia

0 Fabian Hladik 3 months ago in reply to Lucia Gao

Prodigy 20 points

Hi Lucia,

thanks for the reccomendation.

Unfortunately, for this solution we need two different drivers. The goal was, to use only one.

Is there an other "single-driver-soution"?

Thanks in advance.

0 Lucia Gao 3 months ago in reply to Fabian Hladik

TI__Mastermind 30171 points

Dear Fabian,

You can get better efficiency and thermal performance if you use Buck configuration for 3.2V@60mA and 6V@240mA. But if you would more prefer single driver solution, it will also be no problem to use Buck-boost configuration. (TPS923650).

Thank you!

BRs

Lucia

0 Fabian Hladik 3 months ago in reply to Lucia Gao

Prodigy 20 points

Hi Lucia,
Thank you for the information.

One final question:

In order to keep the inductances smaller, I would use the TPS923652 featuring up to 2.2MHz switching frequency.

For the inductance: I will calculate the inductance for all 3 displays and use the largest calculated inducance to be compatible to all 3 displays.

Do you have any concerns with this solution?

0 Lucia Gao 3 months ago in reply to Fabian Hladik

TI__Mastermind 30171 points

Hi Fabian,

Yes, pls keep the largest inductance for 3 different power rails. Thank you!

BRs

Lucia

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TPS923652: Product decision + design