多散热器交扰问题的时域分析

Time-Domain Crosstalk Analysis of Multi-Heatsinks

采用非分裂完全匹配层时域有限差分法(Perfectly Matched Layer Finite-Difference Time-Domain,PML-FDTD)分析同一印制线路板上多个散热器之间的耦合交扰问题。针对不同间距和不同齿槽方向的散热器进行时域分析。仿真结果表明,散热器之间的交扰与其之间的距离成反比。在低频段齿槽方向对散热器的影响较小,对临近散热器骚扰主要归结为PCB板传播的表面波。然而在高频段,散热器齿槽方向对交扰的影响明显,空间的辐射成为对临近散热器骚扰的主要途径。为此在电气产品电磁兼容设计中,应尽可能的增加散热器之间的距离,同时避免多个散热器最大增益方向在同一平面上。

The crosstalk between multi-heatsinks on the same printed circuit board is analyzed by employing unsplit perfectly matched layer finite-difference time-domain method. For different distance between the heatsinks and different directions of teeth and slots, the heatsink is analyzed in time-domain. Simulation results show that the crosstalk between heatsinks is approximately in inverse proportion to its distances. The crosstalks is less effect on direction of teeth and slots of heatsink in the range of low frequencies. The disturbance to the close-by heatsink is mainly attributed to surface wave on PCB. However, in high frequency band, direction of teeth and slots greatly affect the crosstalk. Space radiation is the main path that causes the disturbance to the adjacent heatsink. As a result, in the EMC design of electrical productions, increasing the distance between the heatsinks and avoiding the multi-heatsinks＇ maximum gain direction in the same flat face can reduce the crosstalk of multi-heatsinks.