Dear Mr or Mrs
now we find a problem at our product when we use the MC35FS6513CAE,about the MC35FS6513CAE VSUP power supply pi filter circuit, we design as the below picture:
now the C166 is 100uf ,when the VSUP power rise up to over than 26V,the Vpre down to 2.3V and Vpre_SW down to 0v;
if i change the C166 to 10uf,when the VSUP power rise up to over than 26V,the Vpre is noraml,
so i want to know the reason ,and the L3 and C166 and C165 value requirement;
looks forward your reply ,thanks.
hi guo工
我们尝试将Vsup1&2的电容更改为4.7uf,Vsup3端为100uf电容,VSUP1&2和VSUP3之间的电容为1uh 4020封装的电感,在高温85C和常温25C下测试波形如下,SBC的各个管教输出正常。
但是在低温下会不停复位或者在极端的情况下会将SBC打坏。
测试波形如下:Ch1:Vsup1&2;Ch2:Vsup3;Ch3:Vpre(是Vpre的SW波形),Ch4:current;
-40C的时候波形;
2.85C的测试波形;
想问一下这个是什么原因引起的,设计VSUp1和VSUP3的LC pi型滤波的时候需要注意什么,有什么相关文档对此作出解释吗?因为我找了FS6500的SBC的手册,没有找到任何关于此电感和电容容值的说明,还请帮忙解释一下,谢谢。