Energy efficiency is a major concern in heterogeneous multi-core chips. Due to the switching-capacitor converter (SCC) has wide output voltages and high potential ratio efficiency, they are widely used in multi-core chips. In this paper we propose the optimization of Metal-Insulator-Metal (MIM) capacitance resource allocation and converter ratio selection for SCCs to improve the power efficiency by transforming the mixed integer nonlinear programming (MINLP) problems into a series of convex problems. The experimental results show that our approach can achieve a 9%-13% improvement in power efficiency and can be applied to more complicated heterogeneous multicore scenarios.