Emergency power supply for a lighting apparatus, comprising: - a power supply operatively connectable to the network voltage and provided with at least one main insulation; - an accumulator operatively connected to the power supply; - a flyback power converter comprising a primary having an electronic switch and a secondary, wherein the primary is connected to the accumulator and the secondary, provided with at least one additional insulation, and configured for being electrically and directly connected to cables placed between a network power supply and a light source of the lighting apparatus, thanks to the main insulation and to the additional insulation; wherein said flyback power converter is configured for directly powering the output circuit without switches/relay; - a control unit operatively connected to the power supply, to the accumulator and to the primary of the flyback power converter and configured for detecting the network voltage and for switching the emergency power supply between a first mode of deactivation of the flyback power converter and a second mode of activation of the flyback power converter, wherein in the second mode, the flyback power converter works in discontinuous mode at the switching frequency (f) of the electronic switch; wherein the control unit comprises an activation device configured to activate the flyback power converter, the activation device comprising at least one transistor configured as a comparator, wherein said transistor is configured to turn on when the network voltage exceeds a predefined threshold, and wherein the control unit comprises a voltage detector operatively coupled to a secondary of the power supply and to the transistor, to provide said transistor with a signal in accordance with the network voltage. - a power supply operatively connectable to the network voltage and provided with at least one main insulation; - an accumulator operatively connected to the power supply; - a flyback power converter comprising a primary having an electronic switch and a secondary, wherein the primary is connected to the accumulator and the secondary, provided with at least one additional insulation, and configured for being electrically and directly connected to cables placed between a network power supply and a light source of the lighting apparatus, thanks to the main insulation and to the additional insulation; wherein said flyback power converter is configured for directly powering the output circuit without switches/relay; - a control unit operatively connected to the power supply, to the accumulator and to the primary of the flyback power converter and configured for detecting the network voltage and for switching the emergency power supply between a first mode of deactivation of the flyback power converter and a second mode of activation of the flyback power converter, wherein in the second mode, the flyback power converter works in discontinuous mode at the switching frequency (f) of the electronic switch; wherein the control unit comprises an activation device configured to activate the flyback power converter, the activation device comprising at least one transistor configured as a comparator, wherein said transistor is configured to turn on when the network voltage exceeds a predefined threshold, and wherein the control unit comprises a voltage detector operatively coupled to a secondary of the power supply and to the transistor, to provide said transistor with a signal in accordance with the network voltage.