TPS61196: TPS61196 LED short protection

Mike Wang2

Part Number: TPS61196

hi team,

the ab max voltage for IFBx pins of TPS61196 is rated as 40V. I'd like to check the protection at below situation:

output is pushed to ~100V for many LEDs. if all the LEDs short suddenly, the IFBx voltage may go up to 100V. would IFB pin be damaged?

from the datasheet, it looks the device would remove IFB from the voltage regulation loop. However, the voltage at IFB may still reach 100V.

please help clarify.

thanks

BR,

Mike

over 7 years ago

0 Caryss Li over 7 years ago

TI__Expert 4550 points

Hi Mike,
First of all, if the voltage on IFBx pins are over 40V, the pins will be damaged. As to removing the IFB from regulation loop, it means when the IFB voltage reach FBP set voltage, then it will be remove. It is a logic action and first of all the IFB pin should be survive. If the one or tow LEDs are short during operation, the IFBx voltage will rise and when it reach FBP voltage, this channel will be removed. But even this channel is removed, if high votlage is applied to the pin, that will cause phycical damage to device. That is 40V here, should no be exceeded.

0 Mike Wang2 over 7 years ago in reply to Caryss Li

TI__Intellectual 2760 points

Hi Caryss,

thanks for support.

If remove the IFBx from the voltage loop, the IFBx voltage would be ~ Vout, right?

if the Vout is 100V, and all LEDs shorted, then IFBx would be ~100V, and damaged, right?

thanks,

Mike

0 Caryss Li over 7 years ago in reply to Mike Wang2

TI__Expert 4550 points

Hi Mike,
1. even remove the IFBx from voltage control loop, that means the IFBx pin is high Z, there is little leakage current through LEDs from Vout, the the Vifbx will be Vout-n*Vled, this Vled is smaller than normal operation, you could check in LED datasheet
2. Yes, IFBx will be damaged.

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TPS61196: TPS61196 LED short protection