Dimming LED strip with PWM - Page 1
Forum section: electronics / beginners

author: DCooper
author_rank: Newbie
timestamp: January 13, 2021, 09:52:31 pm
content: Hello!I am going to be dimming 2 meters of LED (Strip). They are 24w per meter. I am looking at one of these two power supplies : Mean Well IDLV-65A-24 or Mean Well SLD-80-24. The dimmer I will use is one bought from ebay, the specs reads : DC 12-40V, Frequency of PWM 13KHZ, Scope of PWM 10-100%, 8A rated.According to the datasheet the IDLV one way to dim it is : "Applying additive 10V PWM signal (frequency range 300Hz~3KHz".So my question is : Will the dimmer be compatible with both of these two power supplies (the SLD-80, doesnt say anything about PWM dimming in the datasheet)? And also, if i choose the ILDV, would it be a problem that its frequency range goes to 3KHz and the dimmer goes to 13KHz?Thank you!

author: tooki
author_rank: Super Contributor
timestamp: January 14, 2021, 06:11:12 pm
content: That dimmer is for directly dimming an LED strip from a non-dimming power supply. It’s not for supplying a PWMcontrol signalto a dimming power supply with an input for that. You’d needanother10V power supply just to run through the dimmer, in the hopes the power supply can handle the out-of-spec frequency.The SLD-80-24 is a non-dimming supply, and probably would work with your dimmer.Both those power supplies are 24V. Do you actually have 24V LED strips, or were you planning to run two standard 12V strips in series?

author: DCooper
author_rank: Newbie
timestamp: January 14, 2021, 08:07:16 pm
content: Thanks for the answer!The strips are 24V. They are meant to be used for film/photography, so they are quite bright I think.So it sound like the SLD-80-24 would be my best bet then.If you dont mind, would you please look at this picture (linked below) from a DIY Perks youtube video called "DIY Studio Lights ", and see if I can wire it the same way? With just one dimmer. And connecting the dimmer to two led strips of 1 meter. I am planning on having them put underneath two shelves, 1 meter on both, and connecting the strips to the same power supply/dimmer.Also, he connects the DC+ to the positive side on the led strip, and then the DC- from the dimmer to the ground (aluminum sheet), which (ground) is then connected to the minus side of the power supply. This is probably a stupid question, but would there be potential of being electrocuted by touching the aluminum plate? If the power supply failed for example.Link :https://drive.google.com/file/d/1k8SzvalR8EIzHwoxpPt_Jt0wdUiNNZgU/viewThanks again!

author: tooki
author_rank: Super Contributor
timestamp: January 15, 2021, 07:01:13 am
content: I remember seeing that video a while back. Yes, you should be able to wire it just like that.If there is any way for the metal to be touched, then forabsolutesafety the metal should be grounded. But if the power supply (with the AC connections) is in an insulated enclosure, with only the 24V output coming out, then it’s safe even without it. (There is, however, a chance the metal may feel “tingly” if it’s not grounded. This is due to the EMI filter capacitors, which allow 1/2 of mains voltage to appear on the DC output, albeit at absolutely microscopic currents. This is normal and doesn’t represent a malfunction or design flaw. Grounding it eliminates it though.)

author: DCooper
author_rank: Newbie
timestamp: January 15, 2021, 09:52:15 am
content: I will just use an insulated wire from the PSU DC negative to negative on the dimmer then, instead of using the metal backing plate. I dont have access to ground in the room that I will mount the LEDs, so probably best to stay on the safe side.Thanks for the help!