A lamp driver comprising: a primary side circuit (PSC); and a secondary side circuit (SSC) isolated from the primary side circuit for delivering an output voltage (V_LED+) and output current (I_LED) to an LED lamp load (LED); an isolating feedback unit (OP_ISOL) for providing a feedback signal from the secondary side circuit to the primary side circuit; an isolated driver circuit (DP, DS) in the form of a transformer-based switch mode power converter and comprising: a primary side (DP) in the primary side circuit (PSC), a secondary side (DS) in the secondary side circuit (SSC) and having a current regulation mode and a voltage regulation mode, wherein the secondary side circuit (SSC) comprises: a current regulating circuit (U1) comprising a current sensor for sensing the output current wherein the current regulating circuit (U1) is for providing the feedback signal based on the sensed output current; an overvoltage protection circuit (U2) for detecting an overvoltage condition of the output voltage and arranged to adapt the feedback signal to provide voltage control during an overvoltage condition; and a modulator (U3) for modulating the feedback signal during detection of the overvoltage condition, thereby resulting in a modulation of the output voltage characterized by : wherein the primary side circuit comprises a controller which is adapted to recognize the overvoltage condition based on a modulation of the output voltage (V_LED+) during an overvoltage protection mode. a primary side circuit (PSC); and a secondary side circuit (SSC) isolated from the primary side circuit for delivering an output voltage (V_LED+) and output current (I_LED) to an LED lamp load (LED); an isolating feedback unit (OP_ISOL) for providing a feedback signal from the secondary side circuit to the primary side circuit; an isolated driver circuit (DP, DS) in the form of a transformer-based switch mode power converter and comprising: a primary side (DP) in the primary side circuit (PSC), a secondary side (DS) in the secondary side circuit (SSC) and having a current regulation mode and a voltage regulation mode, wherein the secondary side circuit (SSC) comprises: a current regulating circuit (U1) comprising a current sensor for sensing the output current wherein the current regulating circuit (U1) is for providing the feedback signal based on the sensed output current; an overvoltage protection circuit (U2) for detecting an overvoltage condition of the output voltage and arranged to adapt the feedback signal to provide voltage control during an overvoltage condition; and a modulator (U3) for modulating the feedback signal during detection of the overvoltage condition, thereby resulting in a modulation of the output voltage characterized by : wherein the primary side circuit comprises a controller which is adapted to recognize the overvoltage condition based on a modulation of the output voltage (V_LED+) during an overvoltage protection mode. a current regulating circuit (U1) comprising a current sensor for sensing the output current wherein the current regulating circuit (U1) is for providing the feedback signal based on the sensed output current; an overvoltage protection circuit (U2) for detecting an overvoltage condition of the output voltage and arranged to adapt the feedback signal to provide voltage control during an overvoltage condition; and a modulator (U3) for modulating the feedback signal during detection of the overvoltage condition, thereby resulting in a modulation of the output voltage characterized by : wherein the primary side circuit comprises a controller which is adapted to recognize the overvoltage condition based on a modulation of the output voltage (V_LED+) during an overvoltage protection mode. <EOS>