A/DC spike pulse absorption circuit

The pulse problem directly affects the EMI and power supply noise of the product, and it is necessary to add a spike pulse absorption circuit at some point.

As can be seen, the peak pulse absorption circuit is an RC absorption circuit. As for where the DC and the RC absorption circuit, there is a rule, that is, when the switch tube on/off, with the inductor to form a circuit.

How do I select RC parameters?

The 1:RC 3dB cutoff frequency is set to 5~8 times the switching frequency to prevent attenuation of the switching signal.

2: Reasonable choice of R, the value is too small over the rated power, the value is too large damping, r fixed, you can find C.

The following data are R=30OHM,C=680PF, calculated f3db=7.8mhz, switching frequency f=1.5mhz. Heavy loads and light load waveforms at the output of the switching tube:

Reference from applications to innovative mobile phone hardware development and design

A/DC spike pulse absorption circuit