DLPS052 October 2015 DLPA3000
The DLPA3000 is designed to be able to deliver a current up to 6 Amps to a LED light source. This maximum current depends on the VLED that is built up over the LED including all series resistances like RON, RWIRE and RLIM (see Figure 6) . The Illum Buck Converter needs some headroom to work properly. This paragraph shows two typical situations for a fixed LED voltage and the accompanying supply voltage range for which a current of 4A or 6A can be delivered. Figure 12 shows the relation between the LED current and the supply voltage for a fixed LED voltage of 5 V, while Figure 13 shows this relation for a LED voltage of 6.3 V. While varying the Supply Voltage the curve shows a constant load current for a given LED voltage above the point where the control loop can maintain a constant current, but the load current drops below the point where the loop is no longer able to keep the current on its value set by the register. This knee-point shifts to higher supply voltage with rising temperature.