The invention discloses a power supply system, which comprises a digital power supply manager and a plurality of power supply modules, wherein each supply power module is used for supplying power to a corresponding load, and comprises a power supply part of a non-isolated DC/DC (Direct Current-Direct Current) converter, a signal sampling and converting circuit for providing analog voltage signals for representing output voltage, output current, temperature and the like, and a driving circuit for receiving a pulse-width modulation (PWM) signal and driving a switching device; a closed loop voltage control and protection function of each power supply module is integrated into a digital power supply; the digital power supply manager comprises a nonvolatile memory containing a register; the register comprises a digital power supply manager configuration register, a power supply module setting register, a power supply module monitoring register and a user customizing space; and the digital power supply manager is used for compiling and monitoring the operation of each power supply module, and can further comprise a user interface such as an I2C interface for receiving programmable data from a host user system and transmitting monitoring data.