A power supply system for a OLED display panel, said system comprising: a power supply circuit including a display driver adapted to be connected to said display panel; a power supply regulator adapted to regulate the power supply voltage of said display driver, and wherein said power supply circuit comprises a protection circuit adapted to protect said display driver against an overvoltage, the power supply system characterised in that: said power supply circuit comprises a switching control circuit (SWREG); said power supply regulator has a supply terminal capable of supplying the power supply regulator with a received loading current; said power supply regulator comprises a transistor (T 1), a diode, a coil and at least one capacitor wherein said transistor (T 1) has a control terminal connected to said switching control circuit (SWREG), a first terminal connected via said coil to said supply terminal, and a second terminal to which a ground voltage (V SS) is applied; wherein said second terminal is connected via said diode to said at least one capacitor, wherein said switching control circuit (SWREG) is adapted to apply a control signal (CRTL) to the control terminal (CT 1) of said transitor (T 1) depending on a monitored positive power supply voltage (PVDD) of said display driver to thereby load said at least one capacitor by said loading current via said coil and said diode, and wherein said protection circuit is adapted to generate an intermediate reference voltage (V MID) applied to a negative supply voltage terminal (ST-) of said display driver to shift the positive power supply voltage (PVDD) of said display driver by a predetermined shift voltage (ΔV). a power supply circuit including a display driver adapted to be connected to said display panel; a power supply regulator adapted to regulate the power supply voltage of said display driver, and wherein said power supply circuit comprises a protection circuit adapted to protect said display driver against an overvoltage, the power supply system characterised in that: said power supply circuit comprises a switching control circuit (SWREG); said power supply regulator has a supply terminal capable of supplying the power supply regulator with a received loading current; said power supply regulator comprises a transistor (T 1), a diode, a coil and at least one capacitor wherein said transistor (T 1) has a control terminal connected to said switching control circuit (SWREG), a first terminal connected via said coil to said supply terminal, and a second terminal to which a ground voltage (V SS) is applied; wherein said second terminal is connected via said diode to said at least one capacitor, wherein said switching control circuit (SWREG) is adapted to apply a control signal (CRTL) to the control terminal (CT 1) of said transitor (T 1) depending on a monitored positive power supply voltage (PVDD) of said display driver to thereby load said at least one capacitor by said loading current via said coil and said diode, and wherein said protection circuit is adapted to generate an intermediate reference voltage (V MID) applied to a negative supply voltage terminal (ST-) of said display driver to shift the positive power supply voltage (PVDD) of said display driver by a predetermined shift voltage (ΔV). said power supply circuit comprises a switching control circuit (SWREG); said power supply regulator has a supply terminal capable of supplying the power supply regulator with a received loading current; said power supply regulator comprises a transistor (T 1), a diode, a coil and at least one capacitor wherein said transistor (T 1) has a control terminal connected to said switching control circuit (SWREG), a first terminal connected via said coil to said supply terminal, and a second terminal to which a ground voltage (V SS) is applied; wherein said second terminal is connected via said diode to said at least one capacitor, wherein said switching control circuit (SWREG) is adapted to apply a control signal (CRTL) to the control terminal (CT 1) of said transitor (T 1) depending on a monitored positive power supply voltage (PVDD) of said display driver to thereby load said at least one capacitor by said loading current via said coil and said diode, and wherein said protection circuit is adapted to generate an intermediate reference voltage (V MID) applied to a negative supply voltage terminal (ST-) of said display driver to shift the positive power supply voltage (PVDD) of said display driver by a predetermined shift voltage (ΔV).