Hi team,
My customer use TPS543B20RVFT in their project.
The waveform was normal when output 3.7V. Now the customer wants to output 4.3 V, and the waveform is abnormal.
1. Initial design(normal):
Input voltage 5V, switch frequency setting 745KHz, output voltage 3.7V .
VOUT=Vref*((R208+R211+R209)/R209)=1.1* ((23.7K+0.02K+10K) /10K) = 3.7 V;
Input voltage 12V, switching frequency setting 745KHz, output voltage 3.7V.
VOUT=Vref*((R208+R211+R209)/R209)=1.1* ((23.7K+0.02K+10K) /10K) = 3.7 V;
2, Change Design(abnormal):
Input voltage 5V, switching frequency setting of 745KHz, expected output voltage 4.3V, but the voltage is like the wave 1 below( The test points are shown by the red arrows in the schematic), the inductance whistles.
VOUT=Vref*((R208+R211+R209)/R209)=1.1* ((26.1K+3.3K+10K)/10K))=4.3V;
Below is the schematic, could you please help give some suggestions? Thank you!
Regards,
Ivy
