LM5175 with analog adjustable current

Martin Hermann

Prodigy 190 points

Other Parts Discussed in Thread: LM5175

Hello,

I would like to use the LM5175 as a led driver.

How is it possible to control the current analog or with a pwm > 1kHz from 0 - 100%?

Regards

Martin

over 8 years ago

0 Vijay86929 over 8 years ago

TI__Genius 11490 points

Hi Martin,

This reference design presents LED driver design usign LM5175.

http://www.ti.com/tool/pmp10592?keyMatch=PMP10592&tisearch=Search-EN-Everything

regards

0 Martin Hermann over 8 years ago in reply to Vijay86929

Prodigy 190 points

Hi Vijay,

thanks. How can I control the current there?

What is the 4 switch buck boost converter (led driver CC or CV) which has the best efficiency at VIn=4,5V/30W and can deliver up to 50W at Vin>8V?
It's difficult to find the answers because the low voltage behavior is not fully explained in all datasheets.

Regards
Martin

0 Vijay86929 over 8 years ago in reply to Martin Hermann

TI__Genius 11490 points

Hi Martin,

That depends. For analog dimming the circuit on the lower left corner of the schematic is needed. It uses an external op-amp for sensing current, the output of which feeds into the FB node of LM5175.

the converter should work down to 4.5VIN. For better operation (sufficient gate drive at low VIN) it is recommended that the VOUT (or other bias source> 7V) be fed to the BIAS pin of the LM5175.

Regards,

0 Martin Hermann over 8 years ago in reply to Vijay86929

Prodigy 190 points

Hi Vijay,

I do not understand the dimming option of the led driver?

Analog? Where is the input?

I only can see several pwm dimming switches.

Regards

Martin

Power management

Power management forum

LM5175 with analog adjustable current