Low battery detection is important in battery-powered systems to alert the user to replace the battery. In some cases, a secondary level of detection is necessary to alert the user of a critical low battery level. Is there a simple circuit that can meet these requirements? Sure there is. We can use the TS12001 nanopower voltage detector device, which combines a 0.58V reference and a comparator with a resettable comparator latch. I invite you to watch this video of a low battery detection circuit using the TS12001. Enjoy.