LM5013-Q1: Is my method for enabling the LM5013 correct?

Hi  Matthew,

Thank you for designing with the LM5013. Could you clarify how to use these two enabling signals, using them in AND or OR logic?   

Thanks,

Youhao

Hello,

it needs to be OR. The active low side is enabled with a momentary switch first which should power on the system and enables an external 12V voltage source which then powers the active high side (both are not active). You then let go of the active low momentary switch and the system stays latched on with the 12V active high circuit until that 12v signal is broken/switched off. If that makes sense! 

Many thanks!

Hi Matthew,

Thank you for the clarification.  Your enabling OR-ing control circuit should work in logic. I just worry about the delay time it may cause because the 100k resistor across the PFET's G and Source, making it hard to discharge during both turn-on and turn-off event. Is it a concern for you?

Thanks,

Youhao

Hi,

I have no timing requirements. Because it is a human pressed switch even if it takes a second to turn on is not an issue.

Thanks!

Hi Mathew,

Then it will be good to go.   Good luck in your project.  May I close this thread, or you want to keep it open for follow-on discussions?

Best Regards,

Youhao

Oh wait, isn't my p channel Q12 and Q13 the wrong way? Looks like source and drain are the wrong way ?

Ah yep the symbol is correct, my footprint is incorrect! Pin 2 is source and 3 is drain, this sybol has 3 as source and 2 as drain, would have caused issues on the actual pcb with that footprint!

Hi Mathew,

Glad that you figured this out before it's too late to correct.  Good luck in your project.

Regards,

Youhao