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]

Hmmm. A converter that drives a boost that in turns drives a bucker, that in turn drives another power supply.

HEY RUBE !!!

[ledcomp]

SCVJeff wrote:
I seriously doubt you will find a pass through unless you build it. I've not seen a board that is a real buck/boost in the literal term. You could always install a boost board to 20v (or whatever), then back it off with the board above. Those boards are so cheap it's fun to try different ones and combos

So then it is safe to have a boost drive a buck that drives a PWM dimmer?

The board you mentioned above requires an isolated ground, my lighting circuit has a common ground. I have not found a common ground version.

[MEXICOWANDERER]

My experience with the B&Bs is similar to gordon three's. With the cost including shipping China Post, the fact that these critters even work, is remarkable. I see my bid for 10 buckers for one cent was successful. Includes shipping. SMD 2-ampere rated. Time to buck those 10-volt 10-watt chips by dialing in the milliamps. For DIY the present is like Alice In Wonderland.

[SCVJeff]

I seriously doubt you will find a pass through unless you build it. I've not seen a board that is a real buck/boost in the literal term. You could always install a boost board to 20v (or whatever), then back it off with the board above. Those boards are so cheap it's fun to try different ones and combos

[GordonThree]

ledcomp wrote:

GordonThree wrote:

ledcomp wrote:

GordonThree wrote:
How well do the LED perform at 9 volts? A straight buck converter would be easier to find than a boost-buck, forward or sepic converter.

Are you dimming all the leds in the rig, or just a strip of them, or a single fixture?

I was trying to regulate the lighting circuit at the distribution panel. 3 lighting fixtures have a pwm dimmer, the rest are not dimmed. I do not mind loosing some brightness by using a buck converter. I would need to try them at 9 volts, that might be on the low side.

A buck that goes into passthrough when vIN = vOUT would work. Set for 11v or even 12v you'll only see that voltage on an almost dead battery.

I have never seen a buck with passthrough. Do you know where i can get one?

Its not really a feature that would be advertised. You'd have to consult datasheets for the various chips China special is using to build these cheap switchers. Some shutdown when vIN=vOUT, others just pass through. Pick up a few cheapies off flea bay and experiment I suppose.

[MEXICOWANDERER]

I Can See It Now Dept -

ROMANTIC CANDLELIGHT DINNER - 2046
After the Carbon Footprint Secretary bans candles...

" Hmmmm; maybe 1.3 Kelvin would be about right with 6, no make that 5 on the Flicker."

[ledcomp]

GordonThree wrote:

ledcomp wrote:

GordonThree wrote:
How well do the LED perform at 9 volts? A straight buck converter would be easier to find than a boost-buck, forward or sepic converter.

Are you dimming all the leds in the rig, or just a strip of them, or a single fixture?

I was trying to regulate the lighting circuit at the distribution panel. 3 lighting fixtures have a pwm dimmer, the rest are not dimmed. I do not mind loosing some brightness by using a buck converter. I would need to try them at 9 volts, that might be on the low side.

A buck that goes into passthrough when vIN = vOUT would work. Set for 11v or even 12v you'll only see that voltage on an almost dead battery.

I have never seen a buck with passthrough. Do you know where i can get one?

[GordonThree]

ledcomp wrote:

GordonThree wrote:
How well do the LED perform at 9 volts? A straight buck converter would be easier to find than a boost-buck, forward or sepic converter.

Are you dimming all the leds in the rig, or just a strip of them, or a single fixture?

I was trying to regulate the lighting circuit at the distribution panel. 3 lighting fixtures have a pwm dimmer, the rest are not dimmed. I do not mind loosing some brightness by using a buck converter. I would need to try them at 9 volts, that might be on the low side.

A buck that goes into passthrough when vIN = vOUT would work. Set for 11v or even 12v you'll only see that voltage on an almost dead battery.

[GordonThree]

SCVJeff wrote:

GordonThree wrote:
How well do the LED perform at 9 volts? A straight buck converter would be easier to find than a boost-buck, forward or sepic converter.

Are you dimming all the leds in the rig, or just a strip of them, or a single fixture?

MY 9v LED arrays are built for 9v. These are flat panels that I stripped all the electronics off and drive them from the new regulator and dimmer. I suspect (unless you can rewire them?) your 12v arrays won't do well @9v.

my led arrays are the same way, three 3v diodes in series, two parallel arrays driven by a constant current led driver in each fixture. there's room on the circuit board to add a microcontroller for dimming, but so far I haven't needed it.

[SCVJeff]

GordonThree wrote:
How well do the LED perform at 9 volts? A straight buck converter would be easier to find than a boost-buck, forward or sepic converter.

Are you dimming all the leds in the rig, or just a strip of them, or a single fixture?

MY 9v LED arrays are built for 9v. These are flat panels that I stripped all the electronics off and drive them from the new regulator and dimmer. I suspect (unless you can rewire them?) your 12v arrays won't do well @9v.

[Vixen21]

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.

It must be this one:LED Light Lamp Strip Dimmer Brightness Adjustable Control 12-24V 8

[ledcomp]

GordonThree wrote:
How well do the LED perform at 9 volts? A straight buck converter would be easier to find than a boost-buck, forward or sepic converter.

Are you dimming all the leds in the rig, or just a strip of them, or a single fixture?

I was trying to regulate the lighting circuit at the distribution panel. 3 lighting fixtures have a pwm dimmer, the rest are not dimmed. I do not mind loosing some brightness by using a buck converter. I would need to try them at 9 volts, that might be on the low side.

[GordonThree]

How well do the LED perform at 9 volts? A straight buck converter would be easier to find than a boost-buck, forward or sepic converter.

Are you dimming all the leds in the rig, or just a strip of them, or a single fixture?

[ledcomp]

MEXICOWANDERER wrote:
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.

I am using a Progressive Dynamics PD-4655 converter. I wouldn't think it would have much effect on it.

If the cap doesn't help i may try an old school regulator. I just hate wasting electrons turning them into heat.