Other Parts Discussed in Thread: LM5143
Tool/software:
Hi experts:
When using the LM5143 power chip, my customer STELL-MATE encountered an EMI radiation problem that exceeded the standard. They make the original fixed frequency (200Khz) change. After changing the DITH pin from pull-up to a 470nf capacitor connected to the ground, the radiation was retested and passed now.
But there are some questions questions:
1. Is Cdith = 470nf a reasonable value (the typical application circuit in the specification uses 10nf)?
2. Does adjusting Cdith adjust the period of the triangle wave?
3. Does changing from fixed frequency to spread spectrum affect the efficiency of the power chip?
4. Does the triangle wave period measured by the DITH pin correspond to the spread spectrum period set by the RT pin? What is the relationship.
Thanks~
