most times uvlo simply uses a comparator with a little hysteresis. VDD is divided down (say in half), and compared to the bandgap voltage. (Say 1.25v) Now your uvlo trips when VDD = 2Vbg or 2.5v. There ya go.
Do you have a bandgap? If not it's a little trickier..
most times uvlo simply uses a comparator with a little hysteresis. VDD is divided down (say in half), and compared to the bandgap voltage. (Say 1.25v) Now your uvlo trips when VDD = 2Vbg or 2.5v. There ya go.
Do you have a bandgap? If not it's a little trickier..
Hi, what if the supply voltage drops to a level that both bandgap and comparator are not able to work, at this moment, the output signal is uncertain, it will be 0.6v or something like that, so how to make sure when VDD drops (under 2Vbg in your case), the UVLO circuit can give a reliable 0V output? Thanks.
how can i do if for high voltage?if i dont' want to waste so much current the voltage divided, another method?as long as i don't want to draw a big resistor in my IC also
thanks
up to about 12v, i usually see resistor dividers of a few hundred k. other alternative is if you have an internal regulated supply voltage, do uvlo on that rather than on the input.