Circuitry for controlling a display matrix formed of light-emitting diodes arranged in rows and columns, diodes in each row being connected to common row lines, and diodes in each column being connected to common column lines, each of the column lines being selectively connected to a current source for...http://www.google.de/patents/US8040339?utm_source=gb-gplus-sharePatent US8040339 - Optimized rowoff voltage
