TPS51396A: Power Input Issue

Hi, 

What is your input voltage? 12V? And what is the VSTB come from? What the VCC is now? Looking forward to your reply. Thanks.

Aurora

Input Voltage is 12V, VSTB is 5V coming from LDO (5V). Vcc is connected internally with LDO

Hi,

I know the VCC is internal 5V VCC LDO output, and it is the power supply for device internal control circuit. If you can not measure 5V VCC voltage, that mean you device may have damaged. Can you change the device and don't use VSTB to power MODE? pls use VCC instead VSTB. And change L7 to 1.5uH. 

Pls try these at first. Thanks.

Aurora

What will be the difference between the powering IC from VSTB to VCC , as we have tested other boards with same older config and its working properly, and also I had got the suggestion for using 2.2uH in TI Web bench simulation and what will be the change occurs by replacing L7 with1.5uH. Can you please Explain in clear technical terms?

Please refer the below pdf for the simulation report.

 WBDesign_Input Transient-3.3V.pdf

Hi,

Because there will have a power-up sequence, so I'm not sure if this cause your problem, pls try this.

For inductance, pls refer to our datasheet suggested value. Thanks.

Aurora

We had set the Mode pins correctly and the Power Good Signals are delivering correct output, then what would be the case for not getting output?

Hi,

Sorry to be a little confused, what is the VCC voltage you measured currently? Is it 5V? Because your initial question description said that the VCC voltage was not measured. Also, can you test whether there is voltage on EN? I am not sure where the EFUSE_GOOD signal is connected to? Because there is no obvious error in other parts of the circuit, please make sure that the chip is powered normally and VCC has a 5V output voltage. Thanks.

Aurora