TPS923652: Looking for LED Flashlight Driver for Cine Apllication

Markus Harthum

Part Number: TPS923652
Other Parts Discussed in Thread: LM3410, , TPS923651, TPS92401

Tool/software:

Hi,

i'm designing a tunable white LED Flashlight for film sets. The two key criteria are fast PWM frequency (above 20khz), and high dimming ratio.
I've done a few designs in the past, where i've used a step up circuit, followed by a linear constant current LED driver. I tried some designs with Boost LED Drivers, like the LM3410 for instance, but i didn't find a product that allowed for the high pwm frequency.

I'm starting a new attempt now, and wanted to reach out to ask, if you can recommend an LED Driver from your portfolio that meets the following criteria:

Input Voltage : 6 to 8,4V
PWM Frequency: 20khz or above
Dimming Ratio at 20khz: 1000:1 or above, or alternative dimming technology that delivers good dimming performance in low levels (hybrid etc)
Needs to drive a 5 to 10 Watt LED. I haven't settled on a specific type yet. There are some interesting ones in the 36V range, but i guess thats too high for the Input voltage, so i also have some lower voltage solutions on hand.

Any help would be greatly appreciated, as i've spent countless hours reading datasheets only to find out in the end that there's one parameter thats not working for me- I figured its probably much quicker for you to just point me at the right driver.

Thanks

Markus Harthum

5 days ago

0 Lucia Gao 5 days ago

TI__Mastermind 30081 points

Hi Markus,

TPS923652 will be a good option for you. It can support 1000:1 dimming ratio. You can select current rating depending on the actual LED current.

Thank you!

BRs

Lucia

0 Markus Harthum 5 days ago in reply to Lucia Gao

Prodigy 40 points

Thanks, wow that was a fast reply. And what about the LP8868 Series?

0 Andy Chen 5 days ago in reply to Markus Harthum

TI__Mastermind 33765 points

are you checking LP8868 for same LED application as above mentioned?

0 Markus Harthum 2 days ago in reply to Andy Chen

Prodigy 40 points

Yes, for the same application.

The datasheet of the TPS looks very good and i think I'll try this one, i just stumbled upon the LP8868 on digikey, and it had very similar specs, so i was curious. Also, for the TPS, there are different current limit versions. Should i take a higher current version to help with thermal problems, even if i wouldnt need it to drive the led?

Thanks

Markus

0 Markus Harthum 2 days ago in reply to Markus Harthum

Prodigy 40 points

And i've seen that the tps923651 also has a very quick PWM response time of 50ns, but i didn't find a dimming ratio specified in the datasheets.

0 Andy Chen 1 day ago in reply to Markus Harthum

TI__Mastermind 33765 points

Hi,

Our expert will check and update you soon,

0 Markus Harthum 1 day ago in reply to Andy Chen

Prodigy 40 points

Hi,

please, no stress, this is a side project and not urgent,

I also just found out about the tps92401 and 92402 dimming modules, and they seem to fit perfectly for my usecase. I think I’ll go with the tps9236xx as boost converter current source, and use the tps92401 for dimming, as i want to control a bicolor led and dont want to use 2 boost drivers to save on board space.

+1 Lucia Gao 15 hours ago in reply to Markus Harthum

TI__Mastermind 30081 points

Hi Markus,

If you need auto version, you can choose LP8868 family. If not, TPS92365x will be a good option. Thank you!

BRs

Lucia

0 Markus Harthum 13 hours ago in reply to Lucia Gao

Prodigy 40 points

Thanks

0 Markus Harthum 13 hours ago in reply to Markus Harthum

Prodigy 40 points

I've read more about shunt fet dimming, and as far as i understood so far, it won't work with boost converter type smps, is that correct?

Power management

Power management forum

TPS923652: Looking for LED Flashlight Driver for Cine Apllication