Energy harvest technology is a technology that converts energy into usable electrical energy using energy that is abandoned or unused in daily life. These energy harvest technologies did not have large applications due to low production power. Recently, however, production power is growing to such an extent that it can be applied to autonomous power plants of smart sensors that have several milliwatts of electricity consumption. In this paper, the power management circuit that drives emergency lighting LED in underground facilities for public utilities using a magnetic energy harvest was designed. The magnetic energy harvest consists of a harvester and a power management circuit. The proposed circuits are power management circuits designed with discrete and power management circuits designed with integrated circuits. The power management circuit for a magnetic energy harvest, designed with discrete, is made of a rectifier, battery charging circuit, and LED driving circuit. Usually, the battery is charged with the power made, and in case of an emergency, the LED is driven using the energy charged in the battery. The measurement showed that it took 2 minutes to charge the 47 mF capacitor. This is the amount of power that can drive an emergency lighting LED for about 3 minutes 30 seconds. The power management circuit for a magnetic energy harvest, designed as an integrated circuit, is designed with a 0.35 μm BCD process. This circuit consists of a rectifier, current mirror, bandgap reference, comparator, and battery, and the simulation confirms that it is sufficient to drive the LED. Through this, it has been confirmed that it can be used as a power source for emergency lighting LED drive in underground facilities for public utilities where it is difficult to draw separate power by using the power management circuit for magnetic energy harvest as suggested in this paper.