LED strip flickers when dimming — possible compatibility issue?

Lighting Installation & Troubleshooting
1

I installed an LED strip lighting system and noticed flickering when dimming. Below is the setup and current behavior:

Using a 24V LED strip
Powered by a 24V constant voltage driver
Connected to a PWM dimmer
Flickering occurs mainly at low brightness levels
At 100% brightness, the strip appears stable

Installation details:
Strip length: approx. 8 meters
Single-side power input
Dimmer rated for higher wattage than the load
No controller other than the dimmer

Questions:

  1. Is this flickering more likely caused by dimmer incompatibility or power supply issues?
  2. Would adding parallel power injection help in this case?
  3. Are certain LED strips more sensitive to low-frequency PWM dimming?
  4. What is the recommended troubleshooting order to isolate the cause?
2

This behavior is very typical of a PWM frequency mismatch rather than a power supply failure. Since the strip is stable at 100% brightness, your driver is most likely working fine. The flickering at low brightness usually means the PWM dimmer output frequency is too low or not well matched to the LED strip’s internal circuit.

For your questions:
1.
More likely dimmer-related than power supply-related.
Many low-cost PWM dimmers work at a few hundred Hz, and some LED strips will visibly flicker at that range, especially at low duty cycles.

Parallel power injection helps with voltage drop, not PWM flicker.
It’s useful for long strips to improve brightness uniformity, but it usually won’t solve flickering caused by PWM frequency.

Yes, some LED strips are more sensitive to low-frequency PWM.
Strips with simpler resistor-based current limiting are especially sensitive compared to strips with better current regulation.

Recommended troubleshooting order:

  1. Test the strip at full brightness → confirm power supply stability
  2. Try another PWM dimmer with higher PWM frequency
  3. If possible, test with a DC analog dimmer (not PWM)
  4. Shorten the strip temporarily (2–3 m) and see if flicker behavior changes
  5. Then consider wiring improvements (thicker wire, dual-end feed)

In most cases, changing to a high-frequency PWM dimmer (≥2 kHz) immediately fixes this type of flicker.

3

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