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4 state illumination controller

Piefairy

Jul 18, 2015
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Alright, I am trying to make a 4 state relay/controller that will cycle through the 4 stages on the change of the input state. Hopefully that makes sense. Basically I only have 1 input to control the brightness, and I need 4 different levels. Off-Low-Medium-High. The input only toggles between on and off, its an IR signal that goes from low to high and remains in that state until the signal is received again. I already have the IR controller done, but I need to figure out how I can make the circuit so it will cycle between the states each time the input trigger changes. I know this should be simple, but its been to many years since I took an electronics class.

The circuit will be driving 4 250mA LED's. Ideally, the circuit will just be opening the relay to allow for the correct voltage to flow to the LEDs. So, basically I have 3 relays that each have a different voltage going to them and I just need to cycle between the 3 and the Off state.

These are links to the power supply and LED's
http://www.luxeonstar.com/1000ma-external-dimming-buckpuck-dc-driver-leaded
http://www.luxeonstar.com/neutral-white-4100K-sinkpad-ii-20mm-star-led-230lm

I may be overlooking something in the driver that would allow for this, I have a similar product that uses this driver for the same application, but I do not have a way to control it in my application.

Please let me know your thoughts and or suggestions.

Thanks in advance.
Pie
 

Alec_t

Jul 7, 2015
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Personally I wouldn't use relays at all. The linked driver can accept an analogue or digital input signal to control LED current (hence brightness) and all 4 LEDs can be connected in series with the one driver. A CD4017 as Colin mentions could be used to provide a 4-level analogue control signal for the driver.
 

Piefairy

Jul 18, 2015
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Sorry for the delay. That does seem a lot easier. My next question would be, if I only want the unit to count to 4, should I then take the output of pin 4 (count 4) to pin 15 (reset) to knock the count back to 0 after it counts 0-1-2-3 for my 4 states correct?

Thanks again for the help.
 

CDRIVE

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The datasheet shows
"0"=Pin3
"1"=Pin2
"2"=Pin4
"3"=Pin7
So, I would think for a count of 4 it would be Pin7 to Reset (Pin15).

Chris
 

AnalogKid

Jun 10, 2015
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Don't think so. 4017 outputs go high, and the reset input is enabled high, so the instant "3" went high it would go low because of the reset. For a 4 count rotating circuit, tie the "4" output to the reset. There will be a very short pulse on the 4 output, but 0-3 all will be normal.

ak
 

CDRIVE

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Oops, I miscounted. As AK said you want it to reset when the count reaches 5.

Chris

Edit: That would be Pin 10.
 

AnalogKid

Jun 10, 2015
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Actually, ak said when the count reaches 4. Talking about the 4017 can be confusing because Reset does not clear all outputs; it puts the counter in its first state, which is called 0. So the 5th state, which is what you use to drive the Reset if you want 4 active states, is called 4.

ak
 

CDRIVE

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Then if he wants a state where all 4 outputs are low he'll need to use Decoded Outputs Q1 through Q5. Where Q5 is used for the Reset jumper to (Reset) Pin15.

Yes, it can get confusing. The older you get the more confused you get! ;)

Chris
 

Piefairy

Jul 18, 2015
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Alright, I am having a bit of a problem understanding how I would make the 4017 control the power supply. From my understanding, you would change the "ctrl" voltage to to change the output amperage of the power supply. Figure 3 on the power supply datasheet shows that it would require 0 to 4v to be applied to the "ctrl" pin. But if we are putting out a digital signal, 001, 010, 011 ect, and not an analog voltage, how would this know to compensate? Or would I need to run through a DaC to convert this back to a straight reference voltage? Or am I wrong and the supply knows out of the box how to decode the digital reference signal? I know it says it takes digital and analog inputs on the description, but I dont see it on the data sheet. I am probably overthinking all of this, but thats just me in general.

Thanks again for the help.
 

AnalogKid

Jun 10, 2015
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Page 2 of the datasheet lists 9 different models of the BuckPuck. We need to know exactly which one you have. It determines the nature of the control circuit. What you want to do might be doable with the 4017 but easier with a different chip.

Also, what are you going to use to power this? Neither of the control pins are at the same potential as the DC input - pin, and this could cause a grounding problem. Fixable, but something to fix.

ak
 

CDRIVE

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The data sheet specs the Control Voltage Input "R" = 1.5KΩ.
This is high enough to use simple (resistive) voltage dividers on the output of most chips. Unfortunately the 4017's outputs are spec'd in the uA range. This limitation doesn't disqualify it though because the outputs can drive emitter followers. The voltage dividers would be connected to the 4017's outputs and the emitter follower's base would connect to the divided nodes. The emitter's would connect to the control voltage input though isolation diodes.

Capice?
Chris
 

Piefairy

Jul 18, 2015
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The specific driver I am looking at is the 3023-D-E-1000 but the 3023-D-I-1000 is an option as well. I am open to other suggestions as well. The driver isn't really the concern, I just know the item I am trying to replicate is using this particular driver. They are also using a PIC and a DaC controller and since I hate coding and don't have a programmer to send the code to the chip, it makes that option undesirable.

A thought I had was using an analog chip, similar to the 4017 and its counter, to open one of three transistors being driven by the power supply. Each transistor would have a fixed value resistor to accomplish the low, medium, high effect. I am not that concerned with efficiency or overheating. The controller I am using has a secondary output that will go off after a 4 minute elapsed time of the LEDs being on. The LEDs also have heatsinks on them for protection. It would only be the transistor and the resistor that would be taking the abuse of the up to 1000mA current.

CDRIVE, I'm not sure if my last paragraph is similar to what you were talking about or not lol. Sorry, I couldn't quite follow where you were going. Or are you saying to drop the transistors and push the outputs through the resistors back to the drivers R and it would detect the change in resistance based on the different amperage change for each of the 4 outputs on the 4017?

Thanks again... and again.... and I'm sure there will be another thanks coming up shortly :p.
 

CDRIVE

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A thought I had was using an analog chip, similar to the 4017 and its counter, to open one of three transistors being driven by the power supply. Each transistor would have a fixed value resistor to accomplish the low, medium, high effect. I am not that concerned with efficiency or overheating. The controller I am using has a secondary output that will go off after a 4 minute elapsed time of the LEDs being on. The LEDs also have heatsinks on them for protection. It would only be the transistor and the resistor that would be taking the abuse of the up to 1000mA current.

CDRIVE, I'm not sure if my last paragraph is similar to what you were talking about or not lol. Sorry, I couldn't quite follow where you were going. Or are you saying to drop the transistors and push the outputs through the resistors back to the drivers R and it would detect the change in resistance based on the different amperage change for each of the 4 outputs on the 4017?

Thanks again... and again.... and I'm sure there will be another thanks coming up shortly :p.

Evidently you didn't understand my last post. If I find time tomorrow I'll post a schematic. BTW, the 4017 is not an analog device.

Chris
 

CDRIVE

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As per my last post I was going to draw up a circuit using transistors to boost the fan-out limitations of the CD4017. I then reconsidered and was going to use an LM324 (Quad OpAmp) to drive the Control Voltage input on the Puck. Glad I didn't bother because there's a higher fan-out equivalent of the CD4017 that can drive the puck's control pin directly.

Check out the Data Sheet for the
MM54HC4017/MM74HC4017 Decade Counter/Divider with 10 Decoded Outputs. It's a pin-out & logic equivalent of the CD4017 but with TTL level supply and outputs. You can power it from the Vref output pin on your puck.

All you would need is resistive voltage dividers on each of the 4 output pins. At that point all four (voltage divider) outputs can be coupled together through 4 diodes with their cathodes connected to the puck's control pin.

Can you follow this or do need a schematic?

Chris
 

Piefairy

Jul 18, 2015
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I think I follow you. I have attached a rough schematic, let me know if its right. I know I dont have power to the puck and the chip needs a ground. Would I need to do a proper voltage divider with 2 resistors per diode or can I work with out the second? Hope you can read the schematic, I have very bad handwriting.
 

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Piefairy

Jul 18, 2015
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Also, I cant seem to find anyone selling the MM54HC4017/MM74HC4017. It seems this is the old National Semiconductor model number? I believe this is the equivalent, but if you could confirm, I would appreciate it. CD74HC4017PWR
 

CDRIVE

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Alec confirmed the chip for you but your circuit design needs invasive surgery. :D

I'll draw it up for you.

Chris
 

CDRIVE

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OK, I need some clarifications.

Since all the incarnations of the 4017 discussed here can provide 10 outputs is 4 all you want? I can design the circuit with more if you like. Currently I'm designing the circuit to provide 5 states, where Q(0) runs the puck wide open. IE CV=0V. The next 4 states would step the CV from ~ 1.0V to 4.0V.

Do you also want an OFF state where the Laser current=0A?

Note: My current design employs very common (1N1183 or 1N914) switching diodes which are easy to find. They can also be substituted with an even more common 1N4002. If you want a Control Voltage step that provides a Laser OFF voltage I will probably have to use Schottky Diodes. Though they're not difficult to find.

Chris
 
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