There is provided a multi-stage power supply. A multi-stage power supply according to an aspect of the invention may include: a voltage converter circuit section including a plurality of first to n-th DC/DC converters connected in series between an input terminal and an output terminal, in order to supply a DC driving voltage to an LED array having a plurality of LEDs therein; a voltage detection section detecting an output voltage from the voltage converter circuit section; and a PWM control section generating a PWM control signal on the basis of a first detection voltage from the voltage detection section, a second detection voltage obtained by detecting current flowing through the LED array, and a third detection voltage obtained by detecting a current waveform flowing through an internal switch of the n-th DC/DC converter, and supplying the PWM control signal to each of the first through n-th DC/DC converters.