From the volt ampere characteristic curve of LED, it can be seen that 10% change of power supply voltage (6v-6.5v) will cause 4 times change of forward current (from 20mA to 80mA). Therefore, UVC should be driven by constant current;

Of course, in the actual use process, many customers will use constant voltage drive. It is also possible to drive UVC by connecting a resistor in series to limit the voltage and current. However, at this time, it should be noted that the VF of UVC is different, and the resistance value of series resistance is different. We can't use the resistance with the same resistance regardless of the voltage of UVC.

Eg: input voltage 12V

UVC voltage 6V, design current 100mA, resistance R1 = (12-6) V / 100mA = 60 Ω

When the UVC voltage is 5.5V, the corresponding resistance R1 = 75 Ω;

When the UVC voltage is 6.5V, the corresponding resistance R1 = 55 Ω;

If the customer's resistance is 60 Ω,

When the UVC voltage is 6V, the UVC current is 100mA;

When the UVC voltage is 5.5V, the UVC current is 125mA;

When the UVC voltage is 6.5V, the UVC current is 91ma;

From the above calculation results, it can be seen that UVC current has a great relationship with UVC voltage (VF value) and series resistance value. Therefore, for some schemes using constant voltage drive through series resistance, we suggest customers to grade according to 0.2V and reduce the fluctuation of UVC current by matching different resistance values.