I recently bought a set of 4 LED strip lights which came with a driver unit but the catalogue listing stated that a transformer was also required. I have installed and connected up the LEDs, the driver and the transformer with a 3amp fuse connection. The LEDS won't illuminate. Please would someone advise me if it is usual to need both a driver and a transformer for LED lighting? Having checked all of the connections (which seem fine)I'm not sure what is wrong! Many thanks in advance.