Current Distribution Optimization of Thyristor Over-Voltage Protectors, by Quasi-3D Simulation
Current Distribution Optimization of Thyristor Over-Voltage Protectors, by Quasi-3D Simulation
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DOI：
10.1109/iccdcs.2006.250883
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发表时间：
2006-04
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影响因子：
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通讯作者：
R. Romo
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作者：
R. Romo
瞬态过电压保护器（TOVP）通常用于电话线路，以防止雷电引起的电瞬变。TOVP基本上是一个四层器件，类似于晶闸管，但没有栅极，并且在阴极和最近的基极之间有许多短路点。其中，短路点控制快速导通瞬态期间的电流分布：电流越均匀，器件的浪涌能力越高。短路点的位置在过去已经通过失效分析方法以及2D模拟和分析方法的组合进行了优化。然而，由于其三维（3D）性质，2D模拟给出了开启过程的不完整画面。另一方面，全3D模拟是不切实际的，因为它们需要在高端工作站甚至超级计算机中进行长时间的计算。利用我们的准三维Spice模拟器，可以快速模拟具有短路点的四层器件的瞬态电流密度分布。这种方法包括将器件分为四层方形棱镜，以及与每个棱镜相关联的1D PNP-NPN晶体管对模型。用Spice在个人计算机上模拟得到的等效电路。本文首次提出了一种基于准三维仿真的双极型TOVP短路点位置优化方法，该TOVP由两个四层器件反并联组成。结果发现，当10 μ s/300 μ s的电流尖峰施加到设备上时，设备的两个部分之间的边界会干扰瞬态电流密度分布，并且可以通过移动50 μ m的短路点的位置来改善该分布。还通过准三维模拟估计并通过二维Atlas电热模拟证实，在100 A/cm 2的阳极电流下，温升小于5 K
Transient over-voltage protectors (TOVP's) are commonly used in telephone lines to ward off electric transients induced by lightning. The TOVP is basically a four-layer device, similar to a thyristor, but without gate, and with a number of shorting dots between the cathode and the nearest base. The shorting dots, among other things, control the current distribution during fast turn on transients: the more uniform the current, the higher the surge capability of the device. The position of the shorting dots has been optimized in the past by failure analysis methods, and combinations of 2D simulations and analytical methods. 2D simulations, however, give an incomplete picture of turn-on processes, because of their three-dimensional (3D) nature. On the other hand, full 3D simulations are impractical because they would require long computation times in high-end workstations and even in supercomputers. With our quasi-3D Spice-based simulator, transient current density distributions of four layer devices with shorting dots can be quickly simulated. This method consists of dividing the device into four-layered square prisms, and a 1D PNP-NPN transistor pair model associated to each of them. The resulting equivalent circuit is simulated with Spice in a personal computer. In the present paper, a quasi-3D simulation-based optimization method for the shorting-dot positions of a bipolar TOVP, consisting of two four-layer devices connected in anti-parallel, is presented for the first time. It was found that the boundary between the two sections of the device disturbs the transient current density distribution when 10 mus/300 mus current spikes are applied to the device, and that the distribution could be improved by shifting 50 mum the position of the shorting dots. It was also estimated, by quasi-3D simulation, and confirmed with 2D Atlas electro-thermal simulations, that at anode currents of 100 A/cm2, temperature rise is less than 5 K