I am working on a project to increase the high power led lamp brightness. In general, there are two ways to do it? One is to increase the voltage/ current from the power supply and install the heat sink accordingly. The other one is to use overdrive pulsed current to boost the brightness.
Can anybody tell me the con and pro and the reasons why for these two methods? By the way, is there any other way to boost the brightness?
The best way to do it is to heat sink the LEDs as well as you can and then increase the current. This is more efficient than pulsing the LEDs at a higher current. As for what current level to drive the LEDs at, you keep increasing the current until either the LEDs stop getting brighter or you reach the continuous current limit specified in the data sheet. If you use decent heat sinking you will usually reach the continuous current limit first. Some LEDs will continue getting brighter as you go past the current limit, but I wouldn't recommend this since it results in much shorter life and much lower efficiency. For example, according to some people's tests here a Luxeon III on a very large heat sink will continue getting brighter up to around 1.2 to 1.4 amps However, the specified maximum for this part is 1.0 amps so that is the most you should drive it at.
If I use pulse to drive the leds, the current limit can go up to 1000ma or 30% higher which can give out more than 110lm according to the chart. If I set the pulse duty to 10% at frequency of 1KHz, this should solve the junction temperature problem. If I use heat sink instead, would the leds give up equivalent or better brightness with the same current range?