TPS922055: High frequency led driver for VLC purpose

Simon Francois

Part Number: TPS922055
Other Parts Discussed in Thread: TPS92641, LM3463

Tool/software:

Hello TI teams,

We are actually working on a project involving to drive high power Led (1000mA min) for visible light comm. system with a DPIM scheme. DPIM meaning the led pulse from off state to on state at different time interval. The pulse length has a period of 500ns.

Is there some TI device that might be suitable to drive the led ?

Thanks in advance for the time taken and wish you a nice day,

Yours faithfully,

Simon François

1 month ago

0 Steven Li 1 month ago

TI__Genius 16630 points

Hi Simon,

Do you have any specific requirements on the output current rising / falling time?

Best Regards,
Steven

0 Simon Francois 1 month ago in reply to Steven Li

Prodigy 70 points

Hello Steven,

Firstly thanks for your answer.

Actually not but as shorter it is better my resolution will be regarding communication purpose.

Thanks you,

Simon

0 Steven Li 1 month ago in reply to Simon Francois

TI__Genius 16630 points

Hi Simon,

Do you have any spec requirements on the input voltage and output voltage (LED forward voltage)?

Best Regards,
Steven

0 Simon Francois 1 month ago in reply to Steven Li

Prodigy 70 points

Yes, it is in order to drive 5 leds and each led has a Vf=3.3v. The entire leds can be driven by a unique driver (but meaning an current of 5A) or each led might have their own driver. Or can also be paired by 2 or 3. Thanks you, Simon

0 Steven Li 1 month ago in reply to Simon Francois

TI__Genius 16630 points

Hi Simon,

How about the input voltage?

Best Regards,

Steven

0 Simon Francois 1 month ago in reply to Steven Li

Prodigy 70 points

Hello Steven,
For this no specific need. Just under 60V

+1 Steven Li 1 month ago in reply to Simon Francois

TI__Genius 16630 points

Hi Simon,

If you just need single digits of microseconds current pulse, then I would say the shunt FET PWM dimming feature of TPS92641 may work.

However, for 500ns current pulse, maybe you need a linear LED driver like LM3463. However, I would say it is still difficult to achieve such short current pulse. (You may achieve a 500ns current output, but the output current waveform may not be a good square wave as you may expect).

Best Regards,

Steven

0 Simon Francois 1 month ago in reply to Steven Li

Prodigy 70 points

Hello Steven,

Thanks for your answer. Do you have exemple with shunt FET PWM feature. I never used it and maybe some circuit exist on this ? Thanks you, Simon

0 Steven Li 1 month ago in reply to Simon Francois

TI__Genius 16630 points

Hi Simon,

You can refer to TPS92641 datasheet. You can also refer to page 6 of this white paper - Common LED Functions and LED Driver Design Considerations.

Best Regards,

Steven

Power management

Power management forum

TPS922055: High frequency led driver for VLC purpose