For applications where higher power LEDs are required and using only one BCR320U would not be sufficient to achieve 350 mA of LED driving current, two BCR320U can be paralleled to spread the current over two devices. For example, by choosing an external 4Ω resistor, the driving current of each branch is about 175 mA. The negative thermal coefficient of the BCR320U ensures that the current consumption is spread evenly amongst the two drivers. This method is also a great way to avoid hot spots on the PCB. Although 12 V and 24 V are the most commonly used voltages in the industry for LED applications, some applications use supply voltages that are greater than the maximum voltage rating of the VEN pin of the BCR320U (24 V) or BCR420U (40 V). The schematic on the right side shows the BCR320U used at a higher supply voltage, eg. +48 V. An external resistor is being inserted between the supply voltage and the VEN pin. The internal resistance of the resistor between the VEN pin and base of NPN transistor is given in the product specification, 10 kΩ. By assuming the voltage for the two diodes at the base of the NPN transistor to be about 1.6 V, the external resistance can be calculated by: (Vs – 25 V) / Rext = (25 V – 1.6 V) / 10 KΩ for Vs = +48 V and Rext = 9.83 KΩ. To confirm that the VEN pin does not exceed the maximum voltage rating, a resistor greater than 10kΩ should be used.