TPS53318: TPS53318 shuts off after working about 15min

bin fu said:

Part Number: TPS53318

Hello,

I am using  TPS53318 for 5V power supply. Vin 19V, Vout 5V.

Design is based on webench and TPS53318 datasheet.

However,after woring about moment,TPS53318 shuts off.TPS53318 is work when I used multimeter to measure the EN‘s voltage.

Could you tell me what happened to my design?

At the beginning I thought it was the cause of overcurrent protection.However,I calculate the Iocp according to the  formula：

fsw=500KHZ

L=4.7μH

Rtrip=76.8K

then the Iocp is about 7A.

My loads has USB camera,mouse and keyboard.

Bin,

I don't see anything obviously wrong with your schematic. What about your PCB? Is it getting hot? can you provide some waveforms? I would recommend triggering on PGOOD going low and capture the event prior and after. I need to see the SW waveform and TRIP to start with.

Hello,John Tucker

     I used the infrared camera to measure the TPS53318,it's about 56°C。However,the ROVP pin was not connected，the datasheet says that the best way it's to be connected GND.Does it effect my design?

     This is the layout(Bottom)

Bin,

It is ok to let ROVP float if not used.

Hello,John

     According to the datasheet, there should be a capacitor next to the VDD pin, but my capacitor is a bit far from VDD, as shown in the red box. Does this have any effect?