TPS2660: Behavior of FLT/ pin with no load at Vout

Tzu-Ping Wu

Prodigy 30 points

Part Number: TPS2660

In my design, when TPS266000 output 24V without load, the FLT/ pin switches back and forth between high and low.

Is the behavior of FLT/ normal?

I cannot find any information in the datasheet.

Anyone can help to explain the behavior of FLT/ when there is no load?

Below please refer to my schematic.

over 7 years ago

0 Karikalan Selvaraj over 7 years ago

TI__Genius 16305 points

Hi

Could you please send a waveform of IN, OUT and FLTb when the problem happens.

We suspect the power supply input is varying causing reverse comparator to trip.
Can you send a oscilloscope waveform.

Regards,
kari.

0 Tzu-Ping Wu over 7 years ago in reply to Karikalan Selvaraj

Prodigy 30 points

Please refer to the attached PDF file with the waveform of IN, OUT, and FLTb.

One more question.

I found a topic labeled as "PS2660: TPS26602 window comparator" .

In that thread, there are 3 proposed method to fix that issue.

1. Reduce the VOUT capacitor OR

2. Increase the VIN capacitor OR

3. Increase the light load current

Following the instruction of the third proposal, my colleague and I added a 1.5 K Ohm resistor/load at the VOUT, , and then the FLT became normal even without the external load, but there would be 1.5 mA current leakage.

Is this modification correct and won't damage TPS26600 itself?

VIN-VOUT-FLTb.pdf

0 Karikalan Selvaraj over 7 years ago in reply to Tzu-Ping Wu

TI__Genius 16305 points

Hi Tzu,

Looking at the waveforms, it is similar issue as reported in the thread "TPS2660: TPS26602 window comparator".

Adding a 1.5k ohm resistor will not harm the device and as per the third proposal it shoud work.

The modificaiton is correct.

Regards,

Kari.

0 Tzu-Ping Wu over 7 years ago in reply to Karikalan Selvaraj

Prodigy 30 points

Hi Kari,

Sounds great and deeply appreciate for your help.

Tzu-Ping

Power management

Power management forum

TPS2660: Behavior of FLT/ pin with no load at Vout