The present invention is aimed at providing an output circuit that is of relatively small scale and may perform adjustment to make the output-signal rise slew rate and the fall slew rate equal to each other. The original image need not be decompressed fully, only to the point of extracting the transform coefficients. A current controller compares sensed current to a reference current and generates a feedback signal, which is processed by a power factor corrector to adjust the current flow through the transformer supplying current to the LEDs.