As the power consumption of microprocessors increase, a multi-phase voltage regulator is required to meet the power hunger and high efficiency requirements. In this paper, in order to design and implementation of a 16 phases DC/DC buck converter, phase extender is applied on the power module of CPU on the motherboard. In this paper, the IC of the phase extender is applied, and which can extend a PWM signal to two interleaved PWM signals. As a result, the purpose of extending 8 phases to 16 phases is achieved, and that can overcome the above mentioned problems. Moreover, the efficiency simulation of 16 phases power consumption is analyzed in this paper, and the experimental results are provided. In order to reduce the phase numbers in the low loading, enhance the phase numbers in the high loading, lower power consumption and increase the efficiency, the phase shedding is used according to the loading.