TPS61165: Need some help for new LED driver design

Nagy Mario

Prodigy 30 points

Part Number: TPS61165
Other Parts Discussed in Thread: TPS61500

Hi Everyone!

First of all, english isn't my native language, so sorry for the language mistakes mistakes.

I hope anyone could help me.

I want a build boost LED driver for 6-8pcs 1W LED based on TPS61165. This device is seems easy to use.

But as soon as i finished first protoboard, i've got a big problem.

My circuit doesn't bost the voltage, and i have no idea what goes wrong.

The input voltage is 12VDC, the output voltage is same as input.

I tried several different inductor value, but nothing changed.

I used my rewok station to solder the parts.

Here's my board layout:

The diode is "MBR0540" which is recommende by the datasheet.

The inductor is "EPCOS B82464P4223M000" (I have a lot of these, so i hope these are ok for DC-DC application)

over 5 years ago

0 Sean Zhou over 5 years ago

TI__Mastermind 22745 points

Hi Nagy,

I'm afraid that it may have lead to the current limit triggered, what you can try is remove the LED counts to 4 or 5 and try again or increase the R1 value to about 4ohm and check whether it works or not.

Sean

0 Nagy Mario over 5 years ago in reply to Sean Zhou

Prodigy 30 points

Hi Sean!

Thanks for your suggestions.

I found some 4,7 ohm resistors, so i replaced the 0,62R to 4,7R, but nothing changed.
The output voltage is still almost the same than input.
If i try light up only 4 LEDS, its working, the Iout is around 44mA which looks ok (0,2v / 4,7r = 0,042A).
One more thing what i didn't mention before:
The CTRL pin is connected to Vin. Later i want add an MCU to my board, but first i want test my driver to see if it works or not.
This can cause the problem? I can't find anything about that in the datasheet.

Regards

Mario

0 Sean Zhou over 5 years ago in reply to Nagy Mario

TI__Mastermind 22745 points

Hi Mario,

It seems that you have triggered the current limit, this means the power has exceeded our power limit. So you may can use our TPS61500 for such kind of power.

Sean

0 Nagy Mario over 5 years ago in reply to Sean Zhou

Prodigy 30 points

Hi Sean!

I will give it a try, the TPS61500 looks better for my application.

Just one more thing...
Are you planning integrate the LED solutions to the new Webench?

I really appreciate your help.

Regards

Mario

0 Sean Zhou over 5 years ago in reply to Nagy Mario

TI__Mastermind 22745 points

Hi Mario,

We have some plans for releasing some simulation models to webench.

SEAN

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TPS61165: Need some help for new LED driver design