Improving an existing LED Driver
Improving an existing LED Driver
(OP)
Hello ! I have a WiFi LED driver that we purchased that has visible flicker when its dimmed below even 80% using its own dimming software. What would you suggest for me to upgrade in order to remove the flicker? What would cause the flicker? In general, how can I improve on an existing driver to help reduce flicker?





RE: Improving an existing LED Driver
Many drivers use PWM to turn the LED on/off quickly.. Persistence of vision makes it look dimmer/brighter to human eyes.. Some are more sensitive than others..
I can't stand LED Christmas lights because I can see the mains freq flicker.. My wife does not notice it at all..
RE: Improving an existing LED Driver
But the speed of your driver may be an issue.
Just how many LEDs are you running, and what driver? Does the driver have it's own internal oscillator?
These are just some questions that could be part of the problem.
With more information you can address what can be done. If at all possible get into a frequency range where
a duty cycle of even 5% won't cause flicker.
RE: Improving an existing LED Driver
Have you tried this controller with different LEDs? That might be the simplest fix.
Z
RE: Improving an existing LED Driver
RE: Improving an existing LED Driver
The same crystal might be used for other purposes, so changing the crystal might have other unwanted impacts.
(edit: e.g. the same crystal might be used as a reference for the wifi chip, or something else in the system. It's very unlikely that the xtal is used only to set the PWM frequency.)
RE: Improving an existing LED Driver
Was this a breakout board you purchased?
If so a link to it could help.
If not a link to your driver and MCU could help.
RE: Improving an existing LED Driver
RE: Improving an existing LED Driver
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers
Of course I can. I can do anything. I can do absolutely anything. I'm an expert!
There is a homework forum hosted by engineering.com: http://www.engineering.com/AskForum/aff/32.aspx
RE: Improving an existing LED Driver
regardless.. there is very little you can do short of making your own controller or finding a different one as you would need to reprogram it and I'm sure you don't have access to the original code nor would it be worth your time to rewrite it from scratch.. (thats not an LED driver BTW).. its simply a controller that just controls each R/G/B channel via PWM'ing a mosfet or transistor.
RE: Improving an existing LED Driver
For example, if your PWM switches 0 - 24 V, your LEDs draw 20 mA, and your PWM switching cycle is 10 us (100 kHz rate), L = 2 * 24 * 10e-6 / 20e-3 = 24e-3 or 24 mH (millihenries). Larger inductors would smooth the current more.
RE: Improving an existing LED Driver
RE: Improving an existing LED Driver
TTFN
I can do absolutely anything. I'm an expert!
homework forum: //www.engineering.com/AskForum/aff/32.aspx
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers
RE: Improving an existing LED Driver
RE: Improving an existing LED Driver
TTFN
I can do absolutely anything. I'm an expert!
homework forum: //www.engineering.com/AskForum/aff/32.aspx
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers
RE: Improving an existing LED Driver
RE: Improving an existing LED Driver
Z
RE: Improving an existing LED Driver
RE: Improving an existing LED Driver
RE: Improving an existing LED Driver
RE: Improving an existing LED Driver
RE: Improving an existing LED Driver
Are you sure they haven't already fixed this problem because others have complained about it? If the issue is on the web or social media there is a good chance that they paid attention and fixed it fast with firmware, so a new unit may not have the same problem.
Z
RE: Improving an existing LED Driver
RE: Improving an existing LED Driver
The issue that you're having with the camera is that the actual time that the detector is actively integrating photons is extremely short, typically less than a few milliseconds. At 10 kHz, you'd get a minimum of 10 PWM cycles within the integration time of the camera, which is what minimizes the observed "flicker."
The simpler solution is to stick a neutral density filter to drop the amount of light coming into the camera to force the camera's AGC to increase the integration time. A 1.0 ND would decrease the light by a factor of 10 and force the integration time to correspondingly increase. If the camera lens has a physical iris, then stopping down the lens would be equivalent.
TTFN
I can do absolutely anything. I'm an expert!
homework forum: //www.engineering.com/AskForum/aff/32.aspx
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers