Patent ID: 7595596

Claim:
A control circuit for an OLED panel, comprising: a plurality of OLEDs respectively located in a corresponding plurality of paths; a current amount determination circuit determining current amounts on said plurality of paths; a voltage supply circuit under control by a control signal, for providing an output voltage to said current amount determination circuit; and a matching feedback adjustment circuit for generating said control signal according to a difference among said current amounts of said plurality of paths, wherein said matching feedback adjustment circuit includes: a minimum signal selector circuit for selecting a signal representing the lowest one of said current amounts of said plurality of paths, a maximum signal selector circuit for selecting a signal representing the highest one of said current amounts of said plurality of paths, and a comparator or an operational amplifier, having inputs respectively electrically connected with said minimum signal selector circuit and maximum signal selector circuit, and an output for generating said control signal, wherein: (a) said matching feedback adjustment circuit further includes a voltage source between said comparator or said operational amplifier and said minimum signal selector circuit, or (b) said minimum signal selector circuit has an internal voltage difference between its inputs, whereby said voltage source, or said internal voltage difference, or a sum of said voltage source and said internal voltage difference, determines a value such that when said difference among said current amounts of said plurality of paths is larger than said value, said voltage supply circuit increases its output voltage; when said difference among said current amounts of said plurality of paths is smaller than said value, said voltage supply circuit decreases or keeps its output voltage.