[CharlieWaffles]

I have two pwm dimmers for some LED circuits in mu panel. I have a device that only illuminates via power pin that is usually controlled by a standard analog (rheostat) style dimmer. I've seen reference to creating a converter to adapt the pwm signal to control analog devices. My PWM dimmer is running at 135hz.

 

[WingsOnWheels]

The most simple solution would be to buy a two-layer POT. One layer drives the PWM, then second is a voltage reference for the other unit. Does the manual for the unit requiring a voltage signal provide a current draw spec? Is it just using the rheostat for a signal or will it draw the lighting current from that source?

You May also want to add a trim POT to either one of the signals so you can adjust the level between the PWM and other unit.

 

[rapid_ascent]

Charlie,

It is possible to convert the PWM into a DC level by building an integrator circuit which gives you the average DC level of the PWM. The PWM to DC is a simple filter. The tougher part is to then buffer it so that you have enough drive current at that DC level to power your load.

There are probably easier ways of doing this so I would suggest you search for those.

 

[az_gila]

What are the analog devices you want to control?

Are they simply light bulbs?

 

[jdeas]

I've seen reference to creating a converter to adapt the pwm signal to control analog devices. My PWM dimmer is running at 135hz.

It could be as simple as a resistor and a capacitor but without more information on the controlled device (I.E. input impedance) It is hard to say.

 

[CharlieWaffles]

It's to drive the illumination for the MH Oxygen 4ip panel unit. I did send a note to them and they said to try to wire it up direct (+vdc) to the PWM as they have a lot of filtering on the input already. If that causes any kind of illumination flicker they said to use a 1K resister and small capacitor. I haven't had a chance to try this yet.

 

[chuckwn]

PWM to Analog Circuit

Here is the circuit we recommend for that purpose.

http://www.fdatasystems.com/Manuals/LC-40_Garmin.pdf

 

[jdeas]

135Hz flicker

No such thing. Once you get much beyond 50hz the eye will no longer see the flicker with those light levels. 135Hz should appear solid. I would be more concerned in possibly hearing 135hz bleed into the audio system.

The circuit Chuck posted should work well if this is only a control voltage and not a load. Make sure to read the note on that page!