VCSEL LED Driver

chentsu chung

Other Parts Discussed in Thread: TPS92515

Now I have a project wnat to use VCSEL LED(see the spec below), input 5V, and control it on for 3ms, off-60ms, on-3ms, off-60ms......

I'm not sure what kind of LED driver I should use. Due to the end device is mobilephone, there is size limitation.

1. Power module: But the FB voltage is too big to do constat current.

2. Illumination Driver: Like TPS92515, but it needs external diode and inductor, the board size is big.

3. Flash LED driver: I'm not sure Flash LED driver could handle such frequent on-off cycle.

PS. The drivering current could up to 3A, it's kind of Laser LED. Based on driver solution, maybe the current spec could modify, but 1.5A at least.

Could you please help to advise any component? Thank you.

over 7 years ago

0 Kenneth Du over 7 years ago

TI__Genius 14295 points

Hi,

Do you need 250mA current?

Thanks.
Regards,
Kenneth

0 chentsu chung over 7 years ago in reply to Kenneth Du

Mastermind 6180 points

Hi Kenneth,

It could be 3A and Vf=2.5V.

But it still depends on the driver solution, but 1.5A at least

0 Irwin Nederbragt over 7 years ago

TI__Mastermind 28655 points

Hello,

The Ppeak doesn't match the current and Vf. If Iled is 3A and Vf is 2.5V that is 7.5W. The TPS92515 can do 2A continuous and should be able to run fairly high frequency at your duty cycle, 3 mS/(3 mS + 60 mS) < 5%. It will be difficult to find a small solution due to the high current requirment.

Regards,

0 chentsu chung over 7 years ago in reply to Irwin Nederbragt

Mastermind 6180 points

Hi Irwin,

Thanks for youre response. I'm not sure how the Ppeak be calcalated, maybe it means the power for a period.

TPS92515 looks okey, but if I need 2A for only 5% duty( so average current is very low just like the performance of Flash LED), this still need such solution?

0 Irwin Nederbragt over 7 years ago in reply to chentsu chung

TI__Mastermind 28655 points

Hello,

The power parts still need to be able to carry the current required. The parts can be smaller since they will not heat as much with less than 5% duty cycle but the MOSFET, inductor and diode have to be able to carry the current. I think it will be difficult to find a complete solution since they are designed for 100% duty cycle. A flash type design, though much smaller duty cycle, may be another starting point.

Regards,

Power management

Power management forum

VCSEL LED Driver