Electronic drive circuits for active matrix devices, and a method of self-testing and programming such circuits

An electronic drive circuit for an active matrix device comprising:

• a plurality of circuit blocks each having a block output for supplying an output signal for the active matrix device,
• at least first and second parallel circuit paths in each circuit block to provide redundancy by alternative routing through the circuit block,
• an output switch connecting the parallel circuit paths of each circuit block to its respective block output for selecting which of the parallel circuit paths provides the output signal from the circuit block,
• a test and control arrangement coupled to the circuit blocks by a circuit path input from one of the parallel circuit paths and via a control output to said output switch, the test and control arrangement having a test input for a test signal for electrically testing at least one parallel circuit path of the circuit block, an internal switch responsive to the electrical testing for electrically switching the test and control arrangement so as to generate a control signal at said control output thereby to select, via the output switch, which of the parallel circuit paths is to provide at the block output the output signal for the active matrix device.