1

I am using ESP12F to drive LED array circuit for dimming and other functions. Supply from LED driver is constant current for LED array. What does ESP12F requires? Constant current or Constant voltage? And what should be minimum amp I should take into consideration. I am considering 3.3v, 1A supply.

MICRO
  • 510
  • 4
  • 25

3 Answers3

2

Most electronic circuits expect CONSTANT VOLTAGE. Only special loads like LEDs need constant current. Note that the ESP gadgets are notorious for wanting a good clean and STIFF power source. Wimpy supplies are reputed to cause the ESP to re-boot from supply droop. The solution to a rather low-current, but STIFF power supply is to use a good size electrolytic capacitor on the supply node.

Richard Crowley
  • 14,382
  • 2
  • 20
  • 37
1

3.3V, 500mA should be enough.

But ... when you doubt whether that ESP module requires constant voltage or constant current, I seriously doubt whether you are the right person for the job.

Wouter van Ooijen
  • 48,407
  • 1
  • 63
  • 136
  • I just had to this myself anyway! So need some suggestions regarding the supply type for ESP. – MICRO Nov 07 '16 at 20:23
  • Regardless of my less knowledge, I had to design the product. I welcome some constructive feedback and some more information on Supply type for ESP module – MICRO Nov 07 '16 at 20:33
  • What do you need to know beyond 3.3V 500 mA and (as Richard hinted) a good sized capacitor? – Wouter van Ooijen Nov 07 '16 at 22:02
  • I find that comment about his qualification pretty out of place. Whether or not he should be doing what he is doing is entirely his business and that of his contractor and has nothing to do with answering his question. – timonsku Jan 26 '17 at 14:58
  • 1
    Whether he does something is up to him and/or his employer. But when someone doubts whether an ESP8266 needs constant current or constant voltage it is my opinion that he/she is not the right person to use that module (and most, if not all, other electronics). That is an opinion I am entitled to. You can of course disagree. – Wouter van Ooijen Jan 26 '17 at 16:00
  • Of course you can have that opinion. I actually think the same as you but I also think that voicing this opinion adds zero value to answering the question and because of that shouldn't be included in an answer. – timonsku Feb 05 '17 at 22:43
  • On that I disagree with you, that's why I included the remark it in my answer. – Wouter van Ooijen Feb 06 '17 at 07:12
0

Supply from LED driver is constant current for LED array.

I am using ESP12F to drive LED array circuit for dimming and other functions

If you are expecting to purchase/use a constant current type LED driver, and you will use PWM for dimming controlled by your ESP12F, then make sure you buy a constant current controller which supports an ON/OFF control line. Some do. Some don't. You want one that does support that feature.

The ESP12F unit you've selected will specify its voltage and current requirements, as well. I gather this is \$3.3\:\textrm{V}\$ and some, as yet unspecified, current compliance. You need to add to that current compliance any outside circuitry that will be driven using the same \$3.3\:\textrm{V}\$ voltage rail. I would tend to imagine that \$1\:\textrm{A}\$ would be more than enough for most uses. But it's better not to guess. Smaller power supplies are smaller, less expensive, dissipate less heat, and just generally are better as long as they provide your needs. So some calculation is usually a good thing.

Now you can examine the constant current LED driver input supply requirements to your ESP12F input supply requirements and make some decision about whether or not these are easily compatible, or if you need to some up with yet another kind of buck or boost converter between them.

You need all this information to work through the steps. You haven't provided anywhere NEAR enough information for any of us to do this for you. We certainly would require knowing which constant current driver you've selected, for example. Since that's absent, I don't think I add much more help here.

An example of an LED control module which includes an ON/OFF control line was mentioned the other day here on EE.SE. It is the Mean Well LDD - H series module. Note that it includes a PWM dimming control!

If you are willing to go the ebay from China or Hong Kong route, you could search for "LED Driver PWM Dimming" and come up with some very cheap modules. Some using the XL4001E1 IC, which includes an Enable pin. I've no experience with these.

jonk
  • 77,059
  • 6
  • 73
  • 185
  • This should be used in Supply for On/Off line? http://www.st.com/content/ccc/resource/technical/document/datasheet/bc/0e/aa/7d/dc/6f/4e/de/CD00087939.pdf/files/CD00087939.pdf/jcr:content/translations/en.CD00087939.pdf – MICRO Nov 07 '16 at 20:49
  • @EmbeddedGeek Why? – jonk Nov 07 '16 at 20:50
  • I am just asking, as you have written the supply should have On/Off control line ? – MICRO Nov 07 '16 at 20:51
  • @EmbeddedGeek I said that the _constant current LED supply_ should have one. I'm assuming from your writing about it that you will select a completely designed module here, because I don't think you can design one. You need to select one that includes an ON/OFF control line. Not an IC here. But a completed module. – jonk Nov 07 '16 at 20:54
  • @EmbeddedGeek I added a link to a constant current supply module that includes a PWM dimming control. Something like that is what I meant to suggest here. – jonk Nov 07 '16 at 21:16