I am testing a 24 V, 40 W LED lamp with the driver HLG-40H-24B (constant current, output 24 V and 40 W) but it does not work correctly: the LEDs flash regardless of the voltage value (from 1 V to 10 V) that is applied in the DIMMING input of the driver.

In RS-Online, I found this document (A guide to buying LED drivers) where it explains that for a LED driver of constant current, it is necessary to choose one with a higher output voltage than the LED lamp (page 4). Is this why the LEDs are blinking? If so, what output voltage and output power should the constant current LED driver have to drive this 24 V, 40 W LED lamp?

  • \$\begingroup\$ You need a constant current driver that is capable of supplying a higher voltage than what the minimum required by the LED lamp is. \$\endgroup\$
    – Andy aka
    Commented Feb 14, 2018 at 16:28
  • \$\begingroup\$ Thanks! Do you think this led driver could work? link \$\endgroup\$
    – FranMartin
    Commented Feb 15, 2018 at 8:51
  • \$\begingroup\$ Is the lamp intended to work on a constant voltage 24V, rather than a constant current driver? You haven't told us what sort of lamp it is. \$\endgroup\$
    – Simon B
    Commented Jun 18, 2023 at 22:20
  • \$\begingroup\$ Please provide documentation for the '40 W LED lamp". \$\endgroup\$
    – Fredled
    Commented Feb 28 at 9:10

1 Answer 1


This driver should work fine.

With the dim wires left open it will supply 1.67A and up to a forward voltage of between 14.4v and 24V.

I suspect your problem is the 0-10V supply circuit.
I do not know what that looks like so I cannot help there.

When I use an HLG with the 0-10v dimming I use a variable bench supply and it always works perfect.

You can easily test by using various batteries for the 0-10v input.

Post your 0-10v dimmer circuit.


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