Timeline for high side switch using NMOS
Current License: CC BY-SA 4.0
9 events
| when toggle format | what | by | license | comment | |
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| Aug 13, 2019 at 11:09 | history | edited | hacktastical | CC BY-SA 4.0 |
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| Aug 13, 2019 at 4:35 | comment | added | Sim Son | That's interesting! Luckily, I mentioned that I'm interested in the tachometer signal, otherwise I would probably have taken an unsuitable solution! | |
| Aug 13, 2019 at 4:27 | vote | accept | Sim Son | ||
| Aug 13, 2019 at 1:58 | comment | added | hacktastical | BLDC motors don't need freewheeling diodes, they have them built in to the coil drives. You only need the diode for a brush motor. As for the noise, flyback was the first place I looked. It doesn't happen with BLDC. Instead, the BLDC motor itself has turn-on inrush - caps to charge, etc. This kicked back on the line when the FET turned on, not when it turned off. | |
| Aug 13, 2019 at 0:41 | comment | added | Sim Son | "is a 4-wire fan completely out of the question?" - the idea is to provide both 3- & 4-pin fan rpm control... | |
| Aug 13, 2019 at 0:35 | comment | added | Sim Son | Thanks for sharing your experience! My final circuit is actually similar to your's, except that I don't have C1 till now (which is the essential difference, I know ;). Are you sure the noise on the 12V-line isn't caused by missing a freewheeling diode, which I guess is mandatory (or is it usually included in the fan's internal circuitry anyway?)? | |
| Aug 12, 2019 at 23:51 | history | edited | hacktastical | CC BY-SA 4.0 |
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| Aug 12, 2019 at 22:58 | history | edited | hacktastical | CC BY-SA 4.0 |
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| Aug 12, 2019 at 22:50 | history | answered | hacktastical | CC BY-SA 4.0 |