Part Number: TPS61196
When TPS61196 drives the LED strings, the EMI radiation test result will over 1.53dB@148.74MHz(as below Figure).
Please recommend how can I do to reduce the value of EMI radiation under 40dB on the schematic.
1. The input loop area (including inductor) and output loop area (including diode) should be as small as possible.
2. The switching node size should be as small as possible.
3. Adding via to SW is not recommended.
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In reply to Yuting Shao:
Thanks for your kind reply. But we can't modify PCB layout because of the customer's schedule.
Could you please recommend how to adjust the specification of components (like capacitor or resistor...etc.) to reduce EMI radiation?
In reply to Terry Tai:
Adjusting the resister and capacitor of MOSFET gate could configure the slew rate. Slower rate is helpful to reduce EMI radiation.
According to your recommend and chapter 184.108.40.206 of TPS61196's specification, it seems to mean R19 resistor.
Should I adjust the resistor value to be above or below 3 Ohm? And, would this adjustment affect other functions?
Larger resister will improve EMI performance but increase switching power loss.
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