Patent ID: 8040339

Claim:
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 said column lines being selectively connected to a current source for providing a current to each of said column lines when said column line is selected, a column voltage being present at a column node of each column line while said column line is selected, each of said row lines being selectively connected to a rowoff voltage for turning off the diodes in that row, the circuitry comprising generating means for generating said rowoff voltage comprising: capture circuitry arranged to capture a maximum value of the column voltages present at the column nodes of a plurality of selected column lines; storage circuitry arranged to store said maximum column voltage; and output circuitry arranged to provide said rowoff voltage based on said maximum column voltage; and voltage offsetting circuitry arranged to offset said maximum column voltage to provide said rowoff voltage, wherein said voltage offsetting circuitry is arranged to produce at one time, based on a plurality of invariable offsets, a plurality of possible voltages, each being offset from said maximum column voltage by a different one of the invariable offsets, and comprises selecting circuitry for selecting one of said voltages to provide the rowoff voltage.