| Electronics > Beginners |
| Voltage regulator inrush current |
| (1/1) |
| LaserTazerPhaser:
Is there any method to implement soft start into this regulator? With small filter cap & load current the overvotlage is large, however with larger caps and high load current there isn't any over voltage however over voltage can occur rapidly if load varies. The current surges during startup and will likely also surge during changes in load current. vreg.asc (2.89 kB - downloaded 61 times.) |
| ledtester:
Posting an image would help out everyone. |
| MagicSmoker:
--- Quote from: LaserTazerPhaser on September 14, 2019, 08:48:27 pm ---Is there any method to implement soft start into this regulator? ... --- End quote --- Yeah, by not using a freaking 555 timer as your controller; you might as well use a potato. |
| ledtester:
It's only going to last for 40us... is that going to be a problem? |
| MagicSmoker:
--- Quote from: ledtester on September 15, 2019, 05:31:24 am ---It's only going to last for 40us... is that going to be a problem? --- End quote --- Inrush in the boost can be a problem if it causes the inductor to saturate and the switch starts switching at that time. And note (to the OP) that inrush is unavoidable in the boost converter because of the direct connection between the input and output, but in low power converters like this it is frequently ignored or only addressed by slowly ramping up duty cycle (because a saturated boost inductor will allow peak current to go too high). In commercial boost PFC stages some of the inrush current is routed around the inductor via another diode in parallel to it, and at higher power levels a conventional precharge resistor with relay/switch bypass is typically used. |
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