Abstract: High voltage drop may result in lacking of supply voltage for macro blocks in voltage islands and thereby circuit failure.Against this issue,a power pad assignment and power mesh topological optimization method is proposed for wire-bonding package chip.In this paper,a spring model is firstly proposed based on physical layout information to determine the power pads for voltage drop optimization.Then,a dense virtual power mesh is constructed and the topology is optimized by an incremental manner.In comparison with fixed power pads and regular power mesh,the experimental results on GSRC benchmarks indicated that the voltage drop of the proposed power assignment method can be reduced up to 26.1%on average,while the resource of the resulted irregular power mesh can be reduced by 84.5%on average.