US Patent 6839057 Circuit for and method of driving current-driven device

Drive circuits are incorporated in an active matrix image display apparatus and drive current-driven devices such as organic EL (electroluminescent) elements. Each of the drive circuits includes a drive transistor for driving the current-driven device and an auxiliary transistor connected parallel to the drive transistor and having a current driving capability which is n times the current driving capability of the drive transistor. In a portion (accelerated period) of a selected period, a drain current flows into the auxiliary transistor and a signal current flowing through a signal line, which represents a current to flow into the current-driven device, is (n+1) times a normal value. As a result, the effect of parasitic capacitors connected to signal lines is reduced, allowing the current-driven devices to be driven with an appropriate drive current even when signal currents are very small.