Patent ID: 7619598

Claim:
An organic light-emitting diode (OLED) passive-matrix display, comprising: a plurality of column conductors extending in a first direction; a plurality of row conductors extending in a second direction transverse to the first direction; a plurality of OLEDs, each associated with a column and a row to allow selection of the OLED; a monitor circuit coupled to the OLEDs to detect a voltage drop across the OLEDs; and a voltage adjusting circuit to supply power to the OLEDs, the voltage adjusting circuit being coupled to the monitor circuit and configured to have two modes of operation: a power-up mode where a reference voltage is used by the voltage adjusting circuit to supply power to the OLEDs and an operational mode where a variable voltage supplied from the monitor circuit is used by the voltage adjusting circuit to supply power to the OLEDs wherein the voltage adjusting circuit includes: a supply node from which voltage can be supplied to the OLEDs; and first and second circuit loops, which are alternatively selectable, the first circuit loop, when selected, coupling the reference voltage to the supply node and the second circuit loop, when selected, coupling the monitor circuit to the supply node and wherein the first and second circuit loops have a common portion that includes a DC-to-DC converter, a switch, and the supply node, the DC-to-DC converter being coupled between the switch and supply node.