Now give a concrete example to illustrate

 Now give a concrete example to illustrate: solar LED lights uses a 12V battery, the load is 8 Series  LED Lamps Bulbs 3 and 1W LED, then the output load voltage is 26.4V roughly current is 1.05A, output power of 27.7 W. If the 12V battery, when the highest voltage is 14.8V, step-up ratio is 1.78, then no radiator QFN package case temperature is about 60 degrees. Also acceptable, but when the battery voltage drops below 10.8V, the step-up ratio becomes 2.44 times, this time the case temperature rises to 70 degrees, and if the TSSOP package, then the case temperature will rise to about 85 degrees, it is not allowed! LED Flexi Strip

In addition to to consider the case temperature, but also consider the maximum input current. SLM2842 maximum input current of 3A. In the calculation of the maximum input current, to consider the efficiency of the constant current module. It is now assumed that 90% is also assumed that the output power is 32W, divided by 0.9 is 35.5W LED Light Module