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RDK-193 driver used with Control4 dimmer

Posted by: PEDRO GIAMMARUSTI on Wed, 02/22/2012

Hello everybody

I`ve tried to use captioned kit circuit driving a Wireless ELV Dimmer manufactured by Control4 and a 5 W LED lamp, it worked very well when an incandescent lamp was placed in parallel with the input and even when it wasn´t except when the dimmer was put in O%.

In this condition,that is no bleeder in parallel and LED lamp switched off LED lamp has flashed for 3 or 4 times and then the dimmer was damaged and stop operating.

The driver itself continues to work well with other low cost TRIAC driven dimmers.

By the performance data shown using the RDK-193 with some other dimmers it seems there was no need for any bleeder or minimum load, more recent designs such as the one introduced in RDR-251 show a 47R resistor in series with the input, acting as a damper, maybe somebody who experienced same problem can help me!

Any good&practical idea is most welcome.


Submitted by PI-Dunwell on Wed, 02/22/2012

Most TRIAC Dimmers (especially the list mentioned on the report) work well with RD-193 and RD-251. I'm not sure what's special with the Control4 dimmer that you have and why it stop working. It Would be great if you have an idea on what the circuit inside it. Open it up!:)

With regards to your bleeder and damper question, bleeder and damper size depends on the TRIAC dimmer parameters. Both RD designs have a passive RC bleeder and active damper. The compatibility list provided on the report shows the TRIAC dimmers where it was tested and works well. The bleeder and damper on the board was chosen with trade-off for efficiency, pF, THD, dimming compatibility, etc. If you want to make it work for a particular dimmer where it fails to work, you need to adjust these components to satisfy the requirement of your dimmer. But again you need to know first why it fail.

Submitted by PEDRO GIAMMARUSTI on Wed, 02/22/2012


Thanks for your comments, now I understand the circuit must be fine tuned according to the TRIAC dimmer parameters, specially its holding current, always attempting to mantain a high figure for circuit efficiency.

Regarding the damaged unit, probably there were some ringing currents caused by misfiring at low conduction angles rising voltage spikes conducted through the closed path including the capacitor placed at the input of the diode bridge.

Probably these voltage transients are not conveniently clipped by the 275 V AC RV, since the dimmer is to be used with 110 V AC mains, suggesting its TRIAC voltage blocking is not that high.

I`ll try to use a bleeder circuit as per DER-314, placed at the circuit input which, altough is more power consuming, seems to be more efficient in creating an AC path for the TRIAC (holding) current.

Please tell me if I´m in the right way, thanks for your help.

Submitted by PI-Dunwell on Thu, 02/23/2012

you're probably right. Other dimmers are sensitive to line and if you don't use the correct line rating, it might give you something you're not going to be happy with. I even encountered some that if you dont use the correct line frequency, it starts to misbehave.

I guess you're in the right direction. You can definitely reduce the ringing by using a passive RC bleeder in order to make the TRIAC happy.

Submitted by PEDRO GIAMMARUSTI on Fri, 02/24/2012


After some time spent trying to minimize ringing at the input finally I`ve found a good solution and the dimmer is working well, no more flickering or flashing of the LED load,

Tks for your comments.