The 7219 'scans' through the digits of the LED's it's displaying. You set the scan current with a single resistor, as I recall.
The difference is, a "constant current" LED driver puts out a lot of current -- up to 20 mA per lit LED. But a 'scanned' LED driver can light up an entire sign on 100 mA or so, spread around fast enough that your eye doesn't see 'flicker'.
Comments
The 7219 'scans' through the digits of the LED's it's displaying. You set the scan current with a single resistor, as I recall.
The difference is, a "constant current" LED driver puts out a lot of current -- up to 20 mA per lit LED. But a 'scanned' LED driver can light up an entire sign on 100 mA or so, spread around fast enough that your eye doesn't see 'flicker'.
Thank You!