• Resolved

LM5145: LM5145 Standby Mode has output of 1.2V

Part Number: LM5145

Hi experts,

Using LM5145 EVM, when controller enters standby mode, there is a approximately 1.2V Vout in over 40s. And I am also wandering why there is a standby mode in almost every buck controllers which are with UVLO. The corresponding pic is shown as below: in which

Red line indicates UVLO;

Blue line indicates VIN;

Sky-blue line indicates Vout.

My questions are:

1. Why controller must feature Standby Mode? Is it because VCC needs time to rise?

2. Why there is a 1.2V output with rise time RC similar to Cout*(Rfb1+Rfb2)?

Thank you very much for your help!