An electrical power supply system, capable of supplying an electrical charge (4; 204) with a predetermined power supply current, comprising a first supply branch (12; 212) and a second supply branch (14; 214) connected in parallel, the first supply branch (12; 212) comprising, connected in series, a first voltage source and a current limiter (56; 256), and the second supply branch (14; 214) comprising a second voltage source, the first voltage source and the second voltage source each having, when they operate normally, a same electromotive force whereof the polarization direction and the amplitude are identical to the polarization direction and the amplitude of the supply voltage, the current limiter (56; 256) comprising a field effect power transistor (58; 258) with a first electrical connection terminal (62; 262) and a second electrical connection terminal (64; 264) and whereof a power channel defined between the first terminal (62; 262) and the second terminal (64; 264) forms an electric dipole connected in series to the first voltage source at the second connection terminal (64; 264), the power transistor (58; 258) having an evolution characteristic of an electrical current passing through the power channel as a function of a differential electrical voltage between the first and second connection terminals (62, 64; 262, 264), the differential electrical voltage being equal to an electrical voltage of the first terminal (62, 262) minus an electrical voltage of the second terminal (64; 264) and the electrical current passing through the power channel having a positive direction when it goes from the first connection terminal (62; 262) toward the second connection terminal (64; 264), the evolution characteristic of the power transistor (58, 258) comprising a first inverse polarization area, wherein the electrical voltage and the current have the same negative direction and the current passing through the channel is not limited, and a second single-direction current limiting area, in direct conduction, in which the differential electrical voltage and the electrical current have the same direction and are positive and the electrical current passing through the power channel is current-limited from a current threshold, wherein the field effect power transistor (58; 258) is a field effect transistor comprised in the family of JFET and MOS transistors, and whereof the semiconducting substrate is made from a material with a wide band gap comprising silicon, silicon carbide, gallium nitride GaN and diamond, preferably silicon or silicon carbide, the field effect power transistor (58; 258) is connected to the first voltage source with an inverse polarization, in a configuration where the voltage differential of the power transistor (58; 258) and the electromotive force of the first voltage source, when the first supply branch operates normally, are opposite, and the first supply branch (12; 212) is configured so that, when a defect occurs on the first voltage source, the electromotive force of the first voltage source is lower than the electromotive force of the second voltage source, the field effect power transistor (58; 258) functions in the second single direction current limiting area and the first supply branch (12; 212) operates as a receiver with respect to the second supply branch (14; 214).