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Multi-Channel LED Drivers Configuration Guide

LED Driver Configurations Guide

In the Multi-Channel configuration, complexity is added to the driver but the system overall becomes much more robust. This configuration is illustrated below in Figure 4.

multi-channel-driver-configuration
 fig. 4

Basic Operation

Assuming again a lamp using 24 LEDs, the LEDs can be broken down, as before, into 4 strings of 6 LEDs each. However, instead of connecting these strings together, they remain independent. The driver is designed to maintain four separate constant current outputs and each of the outputs is connected to one string. This has the advantages of the Series connection in terms of robustness and precision of current regulation in each diode; however it keeps the string voltage as low as the other basic configurations.

Advantages

High accuracy of current regulation can be achieved with minimum string voltages to ease safety considerations. Failures in any one string do not affect the other strings.

Disadvantages

The cost and complexity of the driver is increased somewhat although not nearly as much as four independent drivers.

Failure Modes

If any LED fails short, the other LEDs in that string continue to operate normally and total lamp brightness is impacted only by a factor of 1/n where n is the total number of LEDs in the lamp. If any LED fails open then all of the LEDs in that string cease to operate while the other strings operate normally. In this case, total brightness is impacted by a factor of 1/s where s is the total number of strings in the lamp.