Hi, there, back again.
Anybody could provide some online switch mode adjustable current source design notes? I prefer buck configuration, > 8A reference design.
I designed a buck converter, but I saw some ringing and overshoots, check out the picture here:
using a snubber circuits I can minimize the left lower corner's ringing but I couldn't minimize others, how come?
thanks a lot.
It is not always necessary or desirable to eliminate ringing, and a snubber will only dissipate heat and reduce overall efficiency. The cause of the ringing and overshoot is very likely due to the characteristics of the inductor, the free-wheeling diode, and the output capacitor. It may also be artifacts of the scope probe, or the PCB design. Without more details, such as frequency, component values, slew rates, and voltages, there is not enough information to provide any help. This would be an easy circuit to simulate in LTSpice, where you can add parasitic parameters to duplicate the waveform observed, and then take steps to eliminate them.
Paul
The blue circles enclose noise with the correct timing and polarity to suggest gate drive to the pfet.
Improve local decoupling from the chip ground to Vin.
RL
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