Current-Based Testing of Optical Feedback Pixel Driver

A testing scheme of an optical feedback pixel driver is proposed, discussed and simulated by HSPICE. A basic characteristic of the specific circuit is that the gray scales of the pixel are created by pulse width modulation. So, the integral of the output
I

_pixel
current (which is proportional to
I

_oled
) has to be measured or calculated and used for testing. The testing procedure that is proposed enables the detection and identification of common processing defects up to 96%, as verified from simulation results. Although
I

_pixel
current is tend to be very low, the measuring system used, using special instrumentation ICs, is successfully simulated and verified by HSPICE.