LED diodes from the 230V mains on 2 ways

In the article „Drive LEDs from 230V mains more simply and reliably“ we described to you the principle and usage of current limiting diodes (CLD) in detail. A new type in our offer - CL40M45 features a nominal current of up to 40 mA. Other specification is identical to the type CL20M45, especially Umax 45V and Ptot 1W.
By a simple replacement of CL20 for CL40 we can reach a significant change of a current flowing through LED diodes in the application. This can be convenient for example at designing a device with an adoptable power – at the production, it is possible to choose the type CL20M45 or CL40M45 – depending on customer´s requirements (higher light output or power saving at a lower light output). At the same time, this provides a possibility to reach a wide current range at parallel connection of various CLDs, without a need to modify the PCB.

As it is clear from the first sight, a higher maximum current through a CLD also means a higher heat generated on the chip itself. Both types feature max. power dissipation of 1W, that´s why it is necessary to take this fact into account at the circuit design. While at the CL20M45 it is possible to operate with the continuous current of 20mA up to a maximum operating voltage of 45V (P=0,02Ax45V=0,9W), at the CL40M45 the thermal loss (1,8W) would already be too high. That´s why the maximum continuous operating voltage on the CL40M45 is approx. 25V and the „reserve“ up to 45V is usable for elimination of spikes or disturbances in power supply and similar. For further increasing of durability and reliability, it can be useful to design a PCB with enlarged copper pads serving for trouble-free heat dissipation from the CLD.