Timeline for How does a flyback work when there is no output load?
Current License: CC BY-SA 4.0
11 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Oct 26, 2021 at 0:00 | history | tweeted | twitter.com/StackElectronix/status/1452787079843352577 | ||
| Oct 25, 2021 at 22:44 | history | became hot network question | |||
| Oct 25, 2021 at 16:18 | answer | added | Verbal Kint | timeline score: 3 | |
| Oct 25, 2021 at 15:59 | comment | added | user208862 | To prevent Mosfet damage there should be placed a RCD snubber across primary winding to dump this high voltage spikes. Decreasing the duty by control loop I mention above also help. | |
| Oct 25, 2021 at 15:02 | comment | added | user208862 | Without feedback and duty high enough the output voltage will extremely rise. With feedback the control loop decreases the duty to sufficient value to keep the output regulated (like in loaded state). | |
| Oct 25, 2021 at 14:56 | answer | added | Andy aka | timeline score: 4 | |
| Oct 25, 2021 at 14:54 | comment | added | Bimpelrekkie | Another things is that the system has feedback, it will sense through the feedback winding (the one connected to D2) that there is less load at the output (\$V_{om}\$ will increase) so less energy will be pumped into the transformer by making the pulses on Q1 shorter. | |
| Oct 25, 2021 at 14:53 | comment | added | Math Keeps Me Busy | In additi0n to R0 mentioned above, if the converter is designed to withstand open output (I would hope so), then the caps will slow the rise in voltage enough that the controller has time to react before the voltage rises too much. | |
| Oct 25, 2021 at 14:51 | comment | added | Bimpelrekkie | and so it would build up an extremely high voltage across the MOSFET. Wouldn't this then damage the MOSFET? Of course it would. So the MOSFET will need protection. All MOSFETs have a Drain-Source (actually not Source but Bulk, which is shorted to the Source) diode which will limit the voltage as the polarity of the voltage will reverse (the \$V_{DS}\$ of the MOSFET will be negative. Also there will be a snubber network. | |
| Oct 25, 2021 at 14:43 | comment | added | user16324 | Potentially yes. But see R0 on the other secondary. | |
| Oct 25, 2021 at 14:41 | history | asked | willieb3 | CC BY-SA 4.0 |