Regulation problem with tps84410

Ramu Cherkupally

Other Parts Discussed in Thread: TPS84410

I am using the Tps84410 adjustable regulator to generate +3.3V from a 5V input. I've used the the datasheet to calculate the adjustable resistor in order to set the output to 3.3V. I chose Rset as 459 and Rrt as 348k resistor values so that Vout = 3.3v.

I used all the other suggestions from the datasheet as well for the other discrete components in the circuit and followed the layout design guide down to the letter. My concern is that when the regulator has no load it regulates the 3.3V but when we place the regulator under load (around 4A) the output drops by approximately 120mV.

This 120mV drop under load seems too much of a drop.

Do you have any ideas as to what might be going on?

over 13 years ago

0 J Arrigo over 13 years ago

TI__Mastermind 28020 points

Where are you measuring the 3.3V? Directly at the output pins or at the load? Where do you have the Sense+ line connected?

0 Ramu Cherkupally over 13 years ago in reply to J Arrigo

Prodigy 20 points

Dear J Arrigo,

Thanks for your concern,I took the output at the load of 1 Ohm,where the voltage was dropping to 120mv.when I measure the load at output pins (floating) its giving required volatage of 3.3v.

The sense+ pin is connected to Vout .

0 J Arrigo over 13 years ago in reply to Ramu Cherkupally

TI__Mastermind 28020 points

The module will regulate to the connection point of Sense+. If you connect Sense+ to Vout at the module, any impedance between that point and the load will cause a voltage drop. I would suggest making the output path lower impedance and moving the Sense+ line closer to the load.

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Regulation problem with tps84410