Can anyone help me with connecting multiple LM3914's together. I cant find documentation anywhere for using more than two, and I need 6 tied together (yep, 60 led's). I have breadboarded my 6 and it does work, but the resistor values for Rhi / REF OUT are driving me nuts.
From the data sheets, projects, etc, the values seem to increase (looks like double) as you increase chips, but the LED's brightness changes with each group of 10.
Is there a formula I can use to set these resistors so I can keep the LED current the same with each chip, or do I need to make 6 seperate external references for the chips .
It would also be nice to have an adjustment so I can vary the LED current of ALL 60 together (I need aprox between dim and 8mA as a full 10ma get the chip too warm for my liking)
Any help would be greatly appreciated
From the data sheets, projects, etc, the values seem to increase (looks like double) as you increase chips, but the LED's brightness changes with each group of 10.
Is there a formula I can use to set these resistors so I can keep the LED current the same with each chip, or do I need to make 6 seperate external references for the chips .
It would also be nice to have an adjustment so I can vary the LED current of ALL 60 together (I need aprox between dim and 8mA as a full 10ma get the chip too warm for my liking)
Any help would be greatly appreciated