LED Dimmer

[ledcomp]

I wanted to stabilize my LED lighting circuit voltage using a buck/boost converter. When the LED's are dimmed you can see alot of fluctuation from battery voltage change like when the water pump cycles. My concern is with the PWM LED dimmer being driven by the back/boost converter. I'm trying to not let the magic blue smoke out of my PWM dimmers.

If this will work, does anyone know of a 5 amp+ buck/boost that will work with a common ground?

Thanks
Dave

[MEXICOWANDERER]

Be SURE that adding a cap does NOT affect the voltage status of the converter. I forgot the Fred Flintstone grade ferroresonant converters did not die off when the asteroid hit.

[ledcomp]

MEXICOWANDERER wrote:
I use the $2.95 (8) amp dimmer as found on BuyInCoins.com

A 470uf 25-volt electrolytic capacitor inline BEFORE the dimmer helps.

I will give that a try.

[ledcomp]

GordonThree wrote:

ledcomp wrote:
I wanted to stabilize my LED lighting circuit voltage using a buck/boost converter. When the LED's are dimmed you can see alot of fluctuation from battery voltage change like when the water pump cycles. My concern is with the PWM LED dimmer being driven by the back/boost converter. I'm trying to not let the magic blue smoke out of my PWM dimmers.

If this will work, does anyone know of a 5 amp+ buck/boost that will work with a common ground?

Thanks
Dave

Can you give more details about your existing LED setup and what driver you're using?

Any kind of simple switch mode LED driver isn't going to like you pwm'ing the load downstream of the output.

Typically the smps will have a pwm input or enable input which accepts a pwm signal for dimming.

Alternately with a smps operating in the 10s to 100s of kHz, you can just pwm the driver's power input with a low freq pwm signal (100hz for example). Make sure the driver's soft-start feature is disabled or absent.

This is one of the PWM dimmers that I am using. The other two are similar.

http://www.ebay.com/itm/NEW-DIGITAL-12V-60-WATT-PWM-VARIABLE-BRIGHTNESS-LED-DIMMER-DRIVER-KIT-/360569608805?hash=item53f39f9a65

The led panels are non-regulated from 2011led from ebay.

[MEXICOWANDERER]

I use the $2.95 (8) amp dimmer as found on BuyInCoins.com

A 470uf 25-volt electrolytic capacitor inline BEFORE the dimmer helps.

[GordonThree]

ledcomp wrote:
I wanted to stabilize my LED lighting circuit voltage using a buck/boost converter. When the LED's are dimmed you can see alot of fluctuation from battery voltage change like when the water pump cycles. My concern is with the PWM LED dimmer being driven by the back/boost converter. I'm trying to not let the magic blue smoke out of my PWM dimmers.

If this will work, does anyone know of a 5 amp+ buck/boost that will work with a common ground?

Thanks
Dave

Can you give more details about your existing LED setup and what driver you're using?

Any kind of simple switch mode LED driver isn't going to like you pwm'ing the load downstream of the output.

Typically the smps will have a pwm input or enable input which accepts a pwm signal for dimming.

Alternately with a smps operating in the 10s to 100s of kHz, you can just pwm the driver's power input with a low freq pwm signal (100hz for example). Make sure the driver's soft-start feature is disabled or absent.

[landyacht318]

I've used a booster on a wall wart that was only 11.5 volts and pushed it upto mid 14's, then fed the PWm dimmer with that for a stick and brick project. The Phillips bulb brightness at 14.5 compared to 11.5 was vast. It dimmed pretty well too but got crusty on the low end before the LED just shut off.

I did not run it long, as the LED did not illuminate the surface as nicely as hoped, Halogen it will have to be. Warm white LED is still too artificial looking.

[SCVJeff]

THIS is the one I'm using for my current bedroom fixture project. My arrays are 9V, so I have this one both voltage and current limited and it'll run at full output down to .6v of the set point. It appears that the I/O is common ground, but in my case, unfortunately the downstream dimmer runs an isolated ground to the load 😞