DRIVER APPARATUS AND METHOD

摘要

A driver apparatus is provided for controlling a light source array comprising at least first and second light sources, the light source array used for illuminating a scan region on a target object, wherein light reflected from said target object is captured by a detector. The driver apparatus comprises a single integrated circuit comprising processing means for processing image data received from the detector, a switching array comprising at least first and second switches for switching the respective first and second light sources, and a current source for controlling the flow of current through the light sources. In this way the LED switching circuitry that controls an LED array is placed on the same integrated circuit (i.e. monolithic circuit) as the analogue processing circuitry that processes the image data, with the current source controlling the flow of current through the LEDs in the LED array. The current source has the advantage of avoiding rapid changes or slope discontinuities in the current flowing through the LEDs, which would otherwise cause unwanted transient signals. A shunt path comprising a switching device may be provided in parallel with the LED array and switching array. The shunt path has the advantage of enabling the switching sequence from one LED to another to be controlled such that a substantially constant current is drained from the supply (subject to any differences in the inherent current drawn by the Red, Green and Blue LEDs, respectively).