I plan the 802.3af 5V PD solution, so I used PMP20220 reference design, because my space and cost issue.so my output LC filter must modified.
Modified lists= L6, C15, C16,C17
1. L6=180NH , I hope to 470nH or other value.current, the Irms / Isat over 6A (double current)
2. C15,C16,C17=6.3V 100UFx3pcs change to 10V 22UF (or 47UF).
3. Below is the LC filter's formula, so I can use the formula to get the value for LC. or other formula
3.1 the result's F(Hz) and Z (ohm) must under or over the garget, like: under 22000Hz and 0.5 ohm
circuitcalculator.com/lcfilter.htm
Johnsin Tao:
Hi可以按照你的设计要求修改,可以通过测试结果来验证效果,并不一定要完全按照参考设计。
Gz Wang:
回复 Johnsin Tao:
因为修改后的设计跟参考设计的零件大小跟价格有差异(1210–>1206…),才会想在Layout前确认是否可以正常使用.
Johnsin Tao:
回复 Gz Wang:
Hi一般规格没有问题就可以了,尺寸有的时候只有功耗有关,你需要评估不要过功率即可。