SYSTEM FOR DETECTING A VOLTAGE DROP IN AN AC POWER SUPPLY

A device for detecting a drop in voltage of an AC supply delivering electrical energy to an energy converter in order to supply electrical equipment, the device being connected to an electrical energy reserve for supplying the energy converter. The device includes a full-wave rectifier for rectifying the AC supply, a comparator that compares a first predetermined voltage with a full-wave rectified voltage, a circuit for charging a capacitor in order to charge the capacitor when the rectified voltage is below the predetermined threshold, a circuit for discharging the capacitor in order to discharge the capacitor when the rectified voltage is above the predetermined threshold, a comparator for comparing the voltage at the terminals of the capacitor with a second predetermined voltage, and a circuit for controlling the reserve of electrical energy.