Sleep control of ref195

Yes, this will work. It is important to note that the internal pullup is very low current (8uA MAX, 1-2uA typical), so it may be affected by leakage at that pin, including off-leakage of the MOSFET switch. A resistor-pullup from the SLEEPb pin to Vs would help. A small capacitor from SLEEPb to GND could also help if there is system noise that could interfere with the state of SLEEPb. I would add these to a PCB layout as a way to reduce risk if there is room for them. If they are not required, simply don't install them.

Thank you for your answer.

I think the board space is free so I will add a VS resistor pull-up and capacitor for the SLEEPb pin.

Is it possible to add a pull-down resistor to fix the SLEEPb pin Low during power-on?
Also, could you give me a guideline for the resistor constant?

Sincerely

I'm not sure exactly what you're asking for here. With both a pullup and pull-down resistor you would be setting the SLEEPb pin in the middle, which is not recommended. What resistor constant do you need? Time constant would be RC, with a shift due to the 1uA pullup current.

Thank you for your answer.

I apologize for the lack of explanation, but I was thinking of enabling the power supply after the 15V power supply reaches a certain voltage (15*0.8=12V).

I was thinking of using resistive voltage divider to achieve this configuration, is this possible?

Sincerely