TPS3700

Hi Punyata,

The TPS3700 is a good choice for this application. Vdd can be powered from any rail from 1.8V to 18V, while the equations in section 9.2.2 of the datasheet describe how to set Vmon through a resistor divider to the inputs.

Regards,
David

I've used resister calculator sheet available on website to calculate resistances.I want to know if VDD is same Vmon, and if VDD drops down or is lost, how does it impact the working of circuit.Is circuit able to detect the loss?

Hi Punyata,

If VDD is lost, the IC powers down, The IC and OUTA/OUTB pull-ups fail as well.

If you are looking to see input power fail so your application has time to response, have a look at the TPS3705. This has input power fail detection capability.

Regards,

Thank you for inputs.Do you see any other challenges with my circuit above.I referred to circuit in typical application for detecting Vmon which is same Vdd.

Query : I've two separate 3.3V , one for digital and one for analog.I want to monitor analog one. So if I provide 3.3V digital at Vcc of TPs3700 IC, and analog Vmon 3.3 is lost, would it detect or not?

Hi Punyata,

The resistor values should work as expected.

For monitoring the analog supply you should set your Vcc to the digital 3.3V supply, and your pull-up resistors should be tied to the digital supply. The You can then connect the sense resistor network to the analog supply at the top of the 470k in your schematic - this will let you  monitor the analog 3.3V supply for overvoltage and undervoltage events.

Regards,

David

Would this also let me detect analog power fail condition if I put Vcc of IC to digital 3.3 and monitor analog 3.3

Yes it would.