Hello,

I was wondering if someone could take a look at this LED Driver I am working with and tell me how the Control Inputs are used. They look like simple on off inputs but I don't know if they are routed to ground to be on, or you need a voltage input to trigger the on off.

I attached the cut sheet with the diagram on it. The CTL 1, 2, 3 are what I am looking at.

Thanks in advance

Tim

http://www.diodes.com/datasheets/AL3159.pdf

 

The data sheet is quite clear. An CTL input voltage of less than 0.4V is considered a '0', and greater than 1.4V is considered a '1'. The combination of 1's and 0's determine which LEDs are on.

 

thanks for making it "Quite Clear".

 

There is a truth table on page 6. It is positive true logic.

 

What threw me off was the

Absolute Maximum Ratings table...
VCTL1,2,3 CTL1, CTL2, CTL3 to GND Voltage -0.3 to VIN +0.3 V

thanks for the help guys..

have a good weekend

 

What threw me off was the

Absolute Maximum Ratings table...
VCTL1,2,3 CTL1, CTL2, CTL3 to GND Voltage -0.3 to VIN +0.3 V

This simply means that if your inputs go lower than GND or higher than VIN that the IC will be destroyed.

What's not obvious is that if you have a long signal path from your controlling unit to the IC, and the signals have low transition times, the inductance of the signal path and the capacitance of the IC's input pins comprises a series LC circuit that will "ring" at high frequencies. Adding resistance in the signal path at the IC's input will help to eliminate the ringing, as in the attached simulation.

 

Lord_Baube could have used this last week, but he never posted a drawing, so we couldn't be of much help. Keep it handy. He might come back.

 

I'm not on the board a lot lately, and am not familiar with the post/thread that you are referring to. If you know where the thread is, you might just drop a link to that particular post in it, like this: http://forum.allaboutcircuits.com/showpost.php?p=378520&postcount=6