LP8863-Q1: VDD drawing excessive current of 150mA

Hi 

Could you tell me your detail information about application first.

We are using the LP8863-Q1 to power a 5 string LED back lighting on a LCD. Back light intensity is adjusted using a PWM input from 25% to 75%.

Hi 

I want to konw you series how many LED in one string, the max toltal forward voltage in one string.

We found our issue it appears that the switching FET we used would not work with the LP8863-Q1.  We believe the FETs High Input capacitance was causing the high current draw.

Problem FET NVTFS5C453NLWFTAG - https://www.onsemi.com/pub/Collateral/NVTFS5C453NL-D.PDF

Tried a new FET and everythng seems fine now and the LP8863-Q1 is drawing approx. 40mA.  NVTFS015N04CTAG - https://www.onsemi.com/pub/Collateral/NVTFS015N04C-D.PDF

Could you confirm why NVTFS5C453NLWFTAG was causing the excessive current draw?

Did you review our schematic? Did you see any issues? 

Is there time frame when you can respond to my above questions?

Thanks

Hi Brent,

The team that supports this device is based out of China and this thread has been escalated to their management.  Their responses are delayed due to Chinese New Year.  For this reason, I'm not able to commit a specific date for a reply at this time, but I will continue to monitor and escalate.

-Jim Carrillo

Manager, Online Support

Texas Instruments