Timeline for Drive 24 V LED strip using 3.3 V Wemos D1 mini and MOSFETs
Current License: CC BY-SA 4.0
11 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Aug 14, 2023 at 17:11 | history | edited | evildemonic | CC BY-SA 4.0 |
added 377 characters in body
|
| Aug 14, 2023 at 16:50 | comment | added | Marco Bresson | The two solutions I see now is using the opto-isolators/solid relays solution you mentioned (but with 6 channels, the price can quickly add up to 10€), or to stick to 12V and finding a MOSFET that nicely accept 3.3V betwwen gate and source | |
| Aug 14, 2023 at 16:49 | comment | added | Marco Bresson | Hello again, I lost myself onto the internet for an hour in the quest for answers. I stumble upon this good article baldengineer.com/low-side-vs-high-side-transistor-switch.html that makes me say that what I want to achieve is hard if I stick to NPN BJT and PNP MOSFET as mosfet rarely accept more than 20V from gate to source, and that I'd like my LED strip off when the PWM signal is low. | |
| Aug 14, 2023 at 14:50 | comment | added | evildemonic | I would also put your pull-down resistor on the gate side of that resistor so the MOSFET turns off faster. | |
| Aug 14, 2023 at 14:49 | comment | added | evildemonic | R2 can cause the MOSFET to ring which can burn it up. Gate resistors are used when the gate capacitance is so high you worry about burning out the source driving it. Keep that resistance as low as possible. | |
| Aug 14, 2023 at 14:47 | comment | added | evildemonic | The opto isolator I used as an example is under $1 US, it is up to you to decide what is too expensive. Gate drivers will be much more. | |
| Aug 14, 2023 at 14:47 | comment | added | evildemonic | Replacing the BJT with a MOSFET would work, but again, you will need to do low-side switching because it is the base to emitter (or gate to source) voltage that matters when using transistors. | |
| Aug 14, 2023 at 14:46 | comment | added | evildemonic | It is a feature of all BJT transistors that the base must be a higher voltage than what you want the emitter at or it will be "off". You are attempting "high-side switching" with an NPN. If you want to use an NPN look into low-side switching. | |
| Aug 14, 2023 at 14:39 | comment | added | Marco Bresson | Sorry, I have no idea where the part number of the transistor come from, could it be replaced with another mosfet with 3.3Vgs? I am under the impression that they tend to be cheaper than opto-isolators. What issues would R2 bring? I am curious as I saw other posts mentioning the beter practice of using it. Thank you :) | |
| Aug 14, 2023 at 14:09 | history | edited | evildemonic | CC BY-SA 4.0 |
added 184 characters in body
|
| Aug 14, 2023 at 14:03 | history | answered | evildemonic | CC BY-SA 4.0 |