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. <EOS>