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I have 18W lamps that came with non dimmable led drivers. Ive found datasheet for the main chip (ws3441), which included schematics:

enter image description here and internal block scheme of the chip: enter image description here

I'd like to add dimming controlled with PWM - 1024 levels. I already have PWM part ready - used 6W lamps before successully. They also came with non dimable led drivers but I replaced power adapters to one one 20V with enogh power, which was not sensitive to the shorts in the circuit made by MOSFETs controled by microchip. For 18W lamps I cannot find right power adapter - 70V / >2A. Anyways, I plan to mount those lamps in different rooms so one adapter will not be enough. The best solution would be to make use of those drivers that came with lamps. I've read a bit and searched over internet for solution, found few interesting topics, two of them below:

but I dont know how to get use of that information to resolve my problem. Basically Im taking following solutions into account:

  • somehow disable current sensing and make it fixed (led driver will only be used with this one kind of lamp) so PWM can work properly,
  • maybe using additional transformer like shown here would be solution? enter image description here

Here are photos of the driver:

enter image description here enter image description here enter image description here

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    \$\begingroup\$ Can you ask a clear answerable question? \$\endgroup\$ – Andy aka Aug 19 '18 at 19:07
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    \$\begingroup\$ The original circuit is non-isolated from the AC mains. If you connect any additional circuitry to it without knowing exactly what you are doing you could create a serious safety hazard. \$\endgroup\$ – John D Aug 19 '18 at 19:10
  • \$\begingroup\$ Question is, how to achieve dimming with available hardware? modifications are of course obvious but I'm not looking for answer "buy new driver". \$\endgroup\$ – Michał Majeranek Aug 19 '18 at 19:29
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    \$\begingroup\$ how to achieve dimming with available hardware? Hmm, these drivers are made to a (low) price, the components that are there are to make it do what it does, no more, no less. Generally a driver suitable for dimming is more expensive because it has different (and possibly more) components. If it was easily possible to make a dimmable driver from the non-dimmable design then you would be able to buy those already. So the only answer possible is: buy a new driver. \$\endgroup\$ – Bimpelrekkie Aug 19 '18 at 19:43
  • \$\begingroup\$ what about ideas from attached links? \$\endgroup\$ – Michał Majeranek Aug 19 '18 at 19:46
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You cannot add a dimmer to that fixed output LED driver you are using.

You need to buy another LED driver with a dimmer input.

I would recommend an HLG-40H-xxB where xx = the maximum forward voltage. If the LEDs forward voltage is greater than 54V then a HLG-60H-C will do the job.

An HLG type B can be dimmed with a resistance, 0-10vdc, or PWM.

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  • \$\begingroup\$ this driver is worth 10 times the LED panel... I've decided to take few panels apart and change it to 12V, so they can be powered and controlled by existing instalation. \$\endgroup\$ – Michał Majeranek Aug 22 '18 at 19:25
  • \$\begingroup\$ That driver, new, cost maybe $5. I don't think it is "worth" that much. For the one pictured, I would not give you $1 for it. I would not buy a new one at $5. Why 12V? I know nothing about any panel. This is the first mention of a "panel". aliexpress.com/item/… \$\endgroup\$ – Misunderstood Aug 23 '18 at 0:16

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