—In this paper we propose a hybrid LDO regulator and switching regulator circuit design that uses an LDO regulator instead of a switching regulator to operate in light load. By means of this method our design reduces the power consumption of a switching regulator in light load at the input terminal, and then reduces the power consumption of the server motherboard during the operation. This design includes a microcontroller Unit (MCU) which is able to initialize, detect, judge and control both regulator operations. In addition, the MCU controls both the LDO regulator and the switching regulator in order to transition between light load and heavy load.