In the application example shown on this slide, the R-78S can be put into sleep mode, where it is then powered by its own output through an external buffer capacitor so that it only consumes 7 µA. Therefore, the whole example application above only draws about 20 µW from the capacitor. After a certain discharge time, the voltage of the capacitor drops below a predefined threshold, waking up the application yet again. When the application is in sleep mode for too long, a watchdog function wakes up the R-78S, stopping the voltage of the capacitor from decreasing further and preventing the shutdown of the microprocessor. In certain applications the microprocessor could also be triggered by an external “alarm” signal, waking the application up from sleep mode. When the application is active it draws about 200 µA, which allows the capacitor to be ready again for sleep mode; thus saving valuable battery life. The size of the capacitor has to be scaled according to the desired minimum sleep mode time and depending on the application, the battery life can be prolonged drastically to reach the mythical ten years.