TPS61194: Setting Vout against max LED Vf

Brian Angiel

Part Number: TPS61194

Hi team,

I used TPS61194 in a previous design, which used an LED string with a max Vf of 30.6V. Per the note in Section 7.3.1, I set my Vout to 1.3 * 30.6V = 39.78V. [Related section: "VOUT_MAX voltage should be chosen based on the maximum voltage required for LED strings. Recommended maximum voltage is about 30% higher than maximum LED string voltage."]

In an upcoming design, the LED string I'm using has a max Vf of 37.4V. Taking the same approach, I should have a Vout of 48.62V, which is too high for the device.

So I have two questions:

Am I approaching setting my Vout correctly against my Vf?
Given my new Vf, am I correct in assuming I need to find a new device for this project?

Thanks,

Brian Angiel

over 6 years ago

0 Sean Zhou over 6 years ago

TI__Mastermind 22745 points

Hi Brian,
Yes, your are right. The maximum output voltage of TPS61194 is about 45V. So even you set the OVP point to 48V, it will detect OVP when the output voltage is over 45V. But for your application, if the max vF is 37.4V, I think it's ok to use this device. But you need to make sure the maximum VF with the maximum output current. 30% higher than maximum LED string voltage is a safety value, just for reference.
Regards
Sean

0 Brian Angiel over 6 years ago in reply to Sean Zhou

TI__Expert 4070 points

This is helpful. Thanks, Sean!

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TPS61194: Setting Vout against max LED Vf