Hi team,
The datasheet of TPS562209 in page 13 says to improve efficiency at very light loads consider using larger value resistors, too high of resistance will be more susceptible to noise and voltage errors from the VFB input current will be more noticeable. Here are my three questions, could you please help? Thank you.
1. What does "too high of resistance will be more susceptible to noise" mean? Does it mean that larger resistor has larger thermal noise, so the voltage at VFB pin has larger error?
2. What does "Voltage error from the VFB input current" mean?
3. How can I estimate the error? Is there any document about it?
I have solved customer problems with larger resistors by changing to smaller resistors and would like to share it with you.
My customer wants to get 1.3V output voltage, so he chooses the R2=110k and R3=150k, the waveforms at Vout and SW are as follows. But when I change the R2=20k and R3=27k, the Vout becomes normal.
Best Regards,
Hao
