Hi, I have just ordered several of the S7V8A adjustable voltage regulators https://www.pololu.com/catalog/product/2118 for my project. I am using rechargeable batteries and want to avoid any damage caused by draining them too far. I was wondering if the SHDN input on this regulator could be effectively used for a low-voltage shutoff in the same manner as that described for the S8V3A regulator? (see the “Shutdown” heading in the product description at https://www.pololu.com/catalog/product/2120) I assume that I would have to correct the values in the equation to reflect the different pull-up resistor (100K vs 130K), shut-off voltage threshold (0.4V vs. 1.1V), hysteresis (0.8V vs 0.6V), etc. Will this work the way I want it to? Also, are there any other issues that could be a concern here? Thanks for your help – I’m still a novice when it comes to stuff like this.
Hello.
The configurable shut-down voltage feature of the S8V3A is really unique to that particular regulator, as its shutdown pin serves only one purpose (to shutdown the regulator) and has a very precisely defined voltage (with hysteresis) at which the shutdown occurs. On the S7V8A, the shutdown voltage is not precisely specified, and the pin really is meant to be used as a digital input. I am not sure what your application is, but if your system has a programmable microcontroller, you might use that to monitor the battery voltage and control the enable pin. Alternatively, you might use something like a comparator to control the enable pin.
-Brandon
Brandon, thanks for the info. It would’ve been nice to use it for a low-voltage shutoff, but I will look into the alternatives. Thanks again!