High productivity design

wee960t2e · Wysłany: Pon 4:00, 07 Mar 2011

In response to this target market, currently many major semiconductor manufacturers (including the world-renowned semiconductor manufacturers) have launched their own dimming LED ASIC, but because of the inherent light-emitting principle of LED current dimming LED ASIC available in the market are not yet the case very mature, has its inherent problems, this article will be dimmer view of the current program to make a detailed analysis and present our solution based on MCU dimming.
1 LED light-emitting properties of new technology allows LED current to achieve high power levels,[link widoczny dla zalogowanych], LED power to achieve 1W, and even some to 5W, luminous efficiency to achieve 60-85LM / W, this device is called bright LED LED ( HB-LED). Currently we are using LED lighting on the HB-LED, the LED 1W generally choose the way through the series and parallel composition of high-power LED lights, especially the main series. This LED for 3.4V ± 2%, a forward current of 350mA or so.
The - curve shown in Figure 1.1. Figure 1.1 LED? Curve can be seen from Figure 1 that,[link widoczny dla zalogowanych], when added to the voltage across the LED does not meet 3.4V before,[link widoczny dla zalogowanych], with the increase. When added to the LED when the voltage reaches 3.4V, the change is small,[link widoczny dla zalogowanych], increasing the voltage across the LED will only increase the current flowing through the LED, thus changing the LED brightness, LED increased until the maximum (350MA), LED to achieve maximum brightness. Which has been clamped in (3.4V) or so.