Hello Team,
We use "LM74700-Q1" for reverse current blocking during input short. We connect a BUCK converter behind the MOSFET "RQ5E070BN". Resistive load is connected behind the buck circuit,and the maximum power is 30W, so I think it is suitable for this application.
But we test the "LM74700-Q1" and find it does not work at 15V-input. The "VCAP to ANODE" voltage is close to zero, obviously the charge pump is not working properly. And we have confirm the "EN" is correctly connected to “ANODE”, and they have 15V voltage.
We have debugged and determined that it is not a hardware connection problem, and tried to replace the chip, the problem still cannot be solved. The 22uF capacitors “Cin12 & Cin13” have absorbed most of the switching current ripple, so this will not affect "LM74700-Q1".
Is the chip not suitable for such application, or is there a problem with our circuit parameter design? This problem is very urgent, we hope to get your quick answer. Thank you!
Best regards,
Huichuang