Hello:
When using tps63070, we found that the power supply oscillated hundreds of millivolts in PFM mode. Is it normal? How to improve? thank you
Hello Tao：
It is for the voltage of VIN pin, the voltage / current oscillation amplitude is relatively large in PFM mode, especially the current.
The front stage of tps63070 has a PMOS tube with excessive current. The first half of the waveform is PMOS body diode through current, and the second half of the waveform is the waveform after PMOS channel is opened.
The schematic diagram and test waveform are shown in the figure below:
Hello Tao：
the schematic diagram of tps63070 is as follows. The demand is output current 2A. In the early stage, in order to save layout area and ensure inductance value, two 1.0uh inductors are connected in series. The specifications are as follows.
At present, due to the priority of V_BUS power supply capacity, it can not meet the peak current demand of the system. It is planned to remove one and make room to increase the input capacitance to reduce the power stability of the input terminal. Considering derating and other factors, please help to see if it is feasible to use only one 1.0uh power inductor? thank you!
