What is common cathode LED display technology?

Common cathode LED technology means individual LEDs are connected via their negative ends and driven by positive ends. In common cathode mode, R, G, B chips are separately powered with voltage and current precisely distributed to red, green, and blue diodes, and the current passes the diodes then to the negative ends of ICs.

Common Cathode VS Common Anode LED Schematic Diagram

common anode and common cathode led

What is the difference between the common cathode / common anode LED display?

Power supply direction. With common anode LED displays, the current flows from the PCB board to the led lights, and the RGB led light is uniformly powered, which increases the forward voltage drop of the circuit.  With common cathode LED displays, current passes through the led diode to the IC negative pole as positive. The pressure is reduced and the internal conductive resistance is small. 

Power supply voltage. Typical common anode LED displays send red, green and blue LED diodes voltages higher than 3.8V (such as 5V unified power supply), so the power loss is high. Common cathode LED displays base transmission on the actual voltage required by the red, green and blue LED diodes (the voltage of the red LED diode is about 2.5V and the voltage of the blue and green LED diodes is about 3.8V). This dramatically lowers the heat generated during operations of the display.

Common Anode and Common Cathode Structure Difference in Packaging

Why does common cathode technology generate less heat?

Based on accurate power control, common cathode technology can reduce the power consumption of the entire system by reducing the red LEDs’ supply voltage. Moreover, there are no extra line-scanning devices needed to achieve this. By using common cathode technology, LED display can reduce excessive heat and power consumption, pixel failure rate, and ghost lines (tailing effect), thus improving LED display’s overall performance.

How does common cathode technology save energy?

Electricity& Operating costs. Precision power supply reduces LED display power loss, saving operating costs.

Equipment investment. Lower heat generated from LEDs negates the need for fans and cooling equipment.

Maintenance and repair costs. Electronics are fully enclosed in a die-cast aluminum bottom shell, which provides superior heat dissipation increasing lifespan to about twice that of conventional led screens.

Assuming that under common anode mode a 5V voltage is used as the unified power, under common cathode mode a 2.8V is used for red LEDs, and all other conditions are the same, if the current of red LEDs accounts for 40% of the total current, then we can quickly calculate the percentage of power saved: 40%*(5-2.8)/5=17.6%. If the LED current accounts for 50% of the total current, then we can save 50%*(5-2.8)/5=22%. Therefore, there is a theoretical 17.6%~22% power savings using common cathode technology over common anode technology.