A Discrete High-voltage Power Vdmos Device Spice Macro Model

Today power VDMOSFETs(Vertical Double-diffusion MOSFET) find widespread application in power electronics systems. But the modeling of power VDMOS has been complicated by the various device structures and process, diversified application field, self-heating effect and so on. The lacks of device model in circuit simulators lead to low efficiency, high cost and long product period for circuit and system design. The developing of macro-model for power device is an efficient and attractive solution.This dissertation presents an efficient method to develop the PSPICE macro model for a high voltage N-channel enhanced VDMOS. This model accurately describes both the static and dynamic characteristics of the power device in temperature range from -55℃to 150℃. Furthermore, a thermal resistance ladder model is presented to simulate the maximum peak current capability of this device.At first, the equivalent sub-circuit topology is proposed throughout the analysis of physical phenomena and measured data of the device. It is proved that model based upon physical mechanism often lead to good convergence and high efficiency. The behavior description model can be derived from measured data when the physical equivalence is unavailable. Some measurement methods for power VDMOS are also presented.Second, the model parameters are extracted. Parameters extraction involves three methodologies in this dissertation. (1) The primary is the linear fitting method, which requires some linearization techniques to transform the nonlinear equations. (2) Some parameters are estimated by hand calculation and extracted by the non-linear optimization function of IC-CAP. (3) Some single parameters can be extracted easily by trial and error when the other methods are unavailable or inefficient.At last, the macro model is embedded into PSPICE circuit simulator and then simulated,compared and estimated. It is found that the simulated characteristics have good agreements with the measured ones in the typical operation conditions. And the macro model is satisfied by circuit design.