So I'm getting 3V across the CNTL line, and still just 5V on the REF line. The drop across the 2.2 K resistor is right around 2V.

Don't we want the CNTL line to go to something like 1.5V in order to get the driver to push it to 1000mA?

 

OK, the 2v across the 2.2k resistor indicates a base current of just about 0.91mA, which would allow a saturated collector current of around 9.1mA. That pulls the CNTL line to 5v (REF line) when the output of the 555 timer is high, which should turn off the LED.

Now did you fiddle around with the adjustment of the on-board current control trim pot?

You should not adjust it without using a precision 0.1 Ohm 1% resistor as indicated in the datasheet on page 4, as due to the way the regulator works, just using a DMM set to current won't be accurate.

Datasheet, again: http://www.leddynamics.com/LuxDrive/datasheets/3021-BuckPuck.pdf
Trim pot is in the middle on the side with the pins.

You really need to adjust it by the datasheets' method.

I thought you had 700mA rated LEDs?

Where did I leave my brain?

 

I haven't played with the on board trim adjuster. I saw it, but figured I'd get the circuit worked out before I played with the pot. I figured it was adjusted to the right output, i..e 100% of the rated...is that right?

Do you think my multi-meter (the cheap kind) isn't reading the current right? That may be the problem...maybe it's outputting more current than my meter is showing. Although, I did setup the LEDs (all the colors) with the 1000mA driver directly connected to a battery and the meter did measure 1A current on the LED.

The LEDs are rated for 1000mA (blue, green, white) or 700 mA (red). I just realized the red was 700mA...not 1A. I've been using the 1000mA driver on it, but the meter has been showing only 500mA current. Although...it did just die tonight. I can use the 700mA driver on it and then a 1000mA driver on the green LED.

So, is it working right and I'm not measuring correctly, or am I still doing something wrong? When the LED is constant on...or when I turn the strobe rate way up with the 100k pot, the voltage on the control is 3V for that first buckpuck. And the meter shows 500mA, so that looks correct according to the picture in your post above. But weren't we trying to get it to be around 1.5V when the LED is on and the 555 chip output is low?

Thanks!

Tj

 

I haven't played with the on board trim adjuster. I saw it, but figured I'd get it worked out before I played with the pot. I figured it was adjusted to the right output, i..e 100% of the rated...is that right?

I can't tell you if it was pre-set at the factory or not. The non-adjustable BuckPucks would have to come factory-set.

Do you think my multi-meter (the cheap kind) isn't reading the current right? That may be the problem...maybe it's outputting more current than my meter is showing. Although, I did setup the LEDs (all the colors) with the 1000mA driver and the meter did measure 1A current on the LED.

OK, so is this the same BuckPuck that was putting out 1000mA when it was not connected to Bill's circuit, that is now putting out about 500mA and measuring 3v at the CNTL when the LEDs are on, and about 5v when they're OFF?

The LEDs are rated for 1000mA (blue, green, white) or 700 mA (red). I just realized the red was 700mA...not 1A. I've been using the 1000mA driver on it, but the meter has been showing only 500mA current. Although...it did just die tonight. I can use the 700mA driver on it and then a 1000mA driver on the green LED.

OK, just don't run too much current through your LEDs, or you'll burn them up quickly. I hope you have the LEDs mounted on some kind of heatsink, or they'll get hot and burn up pretty quickly.

So, is it working right and I'm not measuring correctly, or am I still doing something wrong? When the LED is constant on...or when I turn the strobe rate way up with the 100k pot, the voltage on the control is 3V for that first buckpuck. And the meter shows 500mA, so that looks correct according to the picture in your post above. But weren't we trying to get it to be around 1.5V when the LED is on?

OK.
You need to look at the voltages on CNTL when the flash rate is really slow. Better yet, not flashing at all, or in a steady state.

1) Short C1 to ground.
2) Measure/record CNTL with respect to GND.
3) Measure/record the voltage across the BuckPuck input wires (battery).
4) Measure REF with respect to ground. It should be 5v.

5) Short C1 to Vcc.
6) Measure/record CNTL with respect to GND.
7) Measure/record the voltage across the BuckPuck input wires.
8) Measure REF with respect to ground. It should be 5v.

9) Remove the short from C1/Vcc.

 

Alright, dumb question coming...

Shorting C1 to ground, is that the same as removing it from my breadboard and connecting a line to ground to pin 6? An likewise, shorting to Vcc...removing C1 and connecting pin 6 to the positive voltage line out of my battery?

 

Alright, dumb question coming...

Shorting C1 to ground, is that the same as removing it from my breadboard and connecting a line to ground to pin 6?

No, I simply mean to connect a jumper wire from ground to the junction of C1/pin 2/pin 6/R3.

And likewise, shorting to Vcc...removing C1 and connecting pin 6 to the positive voltage line out of my battery?

No, I simply mean to remove the jumper to ground, and then connect a jumper wire from battery + to the junction of C1/pin 2/pin 6/R3.

 

Maybe I'm missing something. When I short to ground, both LEDs turn off. When I short to Vcc, nothing happens--they keep flashing. What am I doing wrong?

 

The C1 near the R3?

 

Yep, that's the one.

 

Shorting C1 will turn on pin 5, and bring pin 9 low. Basically the front circuit is a variation of the 555 Hysteretic Oscillator. Another way of saying the same thing is connecting pin 2 to the negative battery lead.

This sounds like a wiring error. Both squares (555 segments) are inverters, they output the opposite voltage that is on the input.

 

Yep, I agree with Bill. You have a wiring error someplace.

 

A suggestion, for troubleshooting remove the puck buck (if practical). No sense in having the current and light while doing basic measurements.

You should see the following voltages on these pins.

Pins 1,13 - NC (No Connection, will be ground and floating, you shouldn't see any voltage there).
Pin 11 - NC (1/3 Vcc, or 2.3V)
Pins 4,10,14 - 7V (battery voltage)
Pin 7 - 0V
Pin 3 - 1/3 Vcc, or 2.3V
Pins 2,6 - 1/2 Vcc, 3.5V (there will be a triangle wave there)
Pins 5,9 - 1/2 Vcc, 3.5V (50% square wave)

With C1 shorted you will see the following...

Pins 1,13 - NC (No Connection, will be ground and floating, you shouldn't see any voltage there).
Pin 11 - NC (1/3 Vcc, or 2.3V)
Pins 4,10,14 - 7V (battery voltage)
Pin 7 - 0V
Pin 3 - 1/3 Vcc, or 2.3V
Pins 2,6,9 - 0V
Pin 5 - Vcc, 7V

Hope this helps.

 

OK...I'm using a 9V source since I will be using 3 CR 123 batteries. This is what I'm getting. I have some difference from what Bill sent out...

Pins 1,13 - NC
Pin 11 - 5.35V
Pins 4,10,14: 14=2.78V, 10 = 9V, 2 = 9V
Pin 7 - 0V
Pin 3 - 15.3V
Pins 2,6 - 4.5V
Pins 5,9: Pin 5 = 9V, Pin 9 = 4.5V

 

I think I figured out something! I'm not sure what it means, but it's something.

When I do what Wookie Suggests in Post 144 (wow, are we really above 150 posts?) the circuit doesn't behave like he though with his circuit addition in there. As soon as I remove his transistor addition with the 2.2 and 4.7k resistors, then it does what he was thinking--systematically shutting off one LED at a time.

When I short C1 without the Wookie addition in there, then it does turn on the LED on the first buck puck.

Did I put in the Wookie addition wrong?

 

I just re-built the wookie addition:

1. When I short C1 now...both LEDs turn off
2. When I short C1 ro ground, both LEDs turn off
3. When I short C1 to Vcc, both LEDs stay constant on

Any ideas?

 

Disregard all my dumb postings...I figured it out. I am too embarassed to actually admit what I did wrong.

 

It all works! I'm getting 1A on each LED.

But the bad news...I just blew out another LED. I'm not sure what I'm doing, but somehow when I go to measure the current through the LED and then go back to plug them back in...they get killed. Oh well...once I get the system running I hopefully won't be killing LEDs like this. We'll see!

Thanks guys!

Did you get those extra buck pucks in the mail yet?

Tj

 

It all works! I'm getting 1A on each LED.

That's good news!

But the bad news...I just blew out another LED.

That IS bad news. We were trying to avoid that from the beginning.

I'm not sure what I'm doing, but somehow when I go to measure the current through the LED and then go back to plug them back in...they get killed.

Patient: "Doctor! Doctor! It hurts when I do THIS!" (gesturing wildly)
Doctor: "Well then, don't do that."


The great thing about beating your head against a wall is the absence of pain when you stop doing it.

Oh well...once I get the system running I hopefully won't be killing LEDs like this. We'll see!

I don't know why you're killing them. Yet. I don't have any of them to play with, nor any high-power LEDs.[/QUOTE]

Did you get those extra buck pucks in the mail yet?

Not here so far. It'll probably take a few days.

 

Hey guys
I started building the circuit on a PCB.
My soldering is ugly. Any advise? Remember, newbie here so nothing would be too simple. How about soldering iron? Is 25 watts too much, ie too much heat?

 

If you think you're going to use it much a temperature controlled iron is much easier to use. Vellman sells one for around $35 or so.

http://www.vellemanusa.com/us/enu/product/view/?id=522806

They help a lot, because the iron doesn't run away on the temperature.

I have a lot of practice, so I can use the skank irons, but my vellman was a gift. I really like it.