TPS92691 Supply Current and 10 ohm resistor

Samuel Jaffe

Other Parts Discussed in Thread: TPS92691

Hi E2E,

I have a customer who's designing with our TPS92691 LED Driver. The supply goes from 12V to 60V. The datasheet recommends "to bypass the VIN pin with a 0.1-µF ceramic capacitor placed as close as possible to the device and add a series 10-Ω resistor..."

How much current will this 10 ohm resistor carry? The typical application uses a 1206 (1/4W) resistor for an 18V supply. Will this current scale at all with supply voltage?

Thanks!

-Sam

over 8 years ago

0 Clinton Jensen over 8 years ago

TI__Mastermind 25500 points

That resistor will need to carry the IC supply current plus the VCC gate drive current. Neither should scale with the input voltage much at all. But the supply current could be as high as 2.1mA and the gate drive current depends on the gate charge of the FET used and the switching frequency. That current is equal to Fsw*Qg.

0 Samuel Jaffe over 8 years ago in reply to Clinton Jensen

TI__Mastermind 25590 points

I see. Thank you for the info!

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TPS92691 Supply Current and 10 ohm resistor