TPS65265: Power-Up Sequencing Mode-Pin

Hi, Thomas 

Mode pin should be connected to high or floating. 

Hi Zhao,
thanks for the quick reply. 
That's what I did within my schematic. The Mode Pin is floating (0.4 V), but the buck 2 is only working if I supply external voltage to EN2.
Could you maybe review my schematic? How could I send it?
Many thanks!

Thomas

you can attach the schematic here. 

Perfect! Attached you could find my schamatic.

UL =8.4 V

R307/R313 are not equipped.

Did I do anything wrong?

Thx,

Thomas

EN3 should be used to start/stop the power sequence, so EN3 cannot be connected to 5V, and EN3 should come later than EN1/2/MODE. 

Okay, many thanks for the information and your help! 

Now I changed it to the following schematic:

That would be like you proposed right? 

Unfortunately, it is not working like expected.

Do you have any tip here as well?

Many thanks,

Thomas

Hi, Thomas

1. Could measure the EN1, EN2, EN3 for IC24 when power on? 

2. Could measure the EN1, EN2, EN3, and MODE for IC26 when power on? 

Hi Zhao,

See the measured values below. 

IC24
EN1: 1.95 V
EN2: 1.93 V
EN3: 2.08 V
MODE: 0V

IC26
EN1: 2.08 V
EN2: 0.03 V
EN3: 4.89 V
MODE: 0.41 V (also tried pulling it up to 2.08, same source as EN1)

Many thanks and BR

Thomas

Hi, Thomas 

Sorry, I didn't make my questions clear. 

Could you measure the waveforms? I want to check the sequence. 

1. Could you measure the EN1, EN2, EN3 waveforms for IC24 when power on? 

2. Could you measure the EN1, EN2, EN3, and MODE waveforms for IC26 when power on?