What is the difference between common cathode and standard COB?

This refers to how the electrical circuit within the pixel is configured. In a standard (common anode) design, the positive pole of each RGB sub-pixel is shared, and power flows continuously through the circuit. In a common cathode design, the negative pole (the ground, or cathode) is shared instead, and current is only drawn as needed rather than being constantly present.

The practical effect is that common cathode designs generate significantly less heat — around 20% less power consumption in real-world use — because the current is only active when a pixel is being driven. Less heat means brighter sustained output at lower temperatures, a longer lifespan, and reduced running costs. Common cathode is now standard in Flip Chip COB products and is increasingly common in premium SMD designs.