Design and Layout realization of Power MOSFET in Switching Power Supply

In this paper, the circuit and layout of power mosfet in a switching power supply chip are designed. Firstly, according to the requirements of high voltage, large current and latch-up prevention, the switching power devices are selected. According to the on-resistance, the size of the power mosfet is designed, and the layout area of the power mosfet is obtained. On the basis of studying various routing methods, the cross-fingered routing method is proposed to enhance the current carrying capacity of the underlying metal. The slots are adopted to reduce the metal stress. Taking the slots into account, the widths of metal wires are calculated according to current carrying capacity and electromigration characteristics. Finally, the correctness and reliability of the layout design are verified by the simulation after extracting parasitic parameters.