can you give me the supply current consumption (@12V) when the LM3481 is in shutdown by appying "Low" to UVLO?
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I would believe that it is similar to an over temperature condition where the part will draw around 10 .. 15 µA.
But I am not sure, so I would need to find an expert who can answer that. This will take some days.
May I ask why you need to know that number?
For a proper shutdown the FA/SYNC/SD pin has to be pulled high rather than pulling the UVLO pin low.
See Figure 27. Shutdown Operation in Frequency Adjust Mode in the datasheet, how this should be implemented.
When the desired voltage of the supply has been reached, the FET should be turned on.
I have received the following information:
For the UVLO pin, there are three conditions:
- UVLO<0.7V = everything is off inside the IC, and it will run a couple uA. This is an equivalent state to FA pin being pulled high, although the bias current might be slightly different (still all in the 5uA range)
[As I had mentioned eralier, to be on the safe side, I would assume a current draw of around 10 .. 15 µA, similar to the over-temperature condition.]
- 0.7V<UVLO<1.43V = everything in the IC is biased up. However, the internal SS is discharged, and switching is not allowed
- UVLO>1.43V = normal operating condition
So, you must make sure that ULVO will always stay below 0.7V to remain in the low power state.