Drive circuit, the drive circuit can be roughly divided into direct drive and constant current drive.
The current of the direct drive circuit is not controlled. When the battery power is high enough, the battery will do its best to supply the LED. At the beginning, the flashlight will be bright, the temperature will rise in vain, and the heat and heat will not be balanced. After the battery is gradually exhausted, the brightness and temperature will gradually decrease. This circuit is too high in the previous period, and the damage to the LED and the battery is very large. The life of the lED often cannot reach the design life, and the battery will also have an overload working life. shorten. This kind of "quick success" is not limited to the flow of the driver, only the low-end flashlight will see. For the long-range meaning, the long-range effect in the early stage of the flashlight work will be better, and the long-range ability will be weakened rapidly as time progresses.
The constant current driving current belongs to the current mainstream driving scheme. The circuit controls the current supplied to the LEDs to keep the current at the same level. For example, the XM-L T6 is driven with a constant current of 2.0A and the brightness is always maintained at 700 lumens. After the current is constant, the heat and heat dissipation of the flashlight are also balanced, and the output current of the battery can be maintained. This is the optimal drive solution. Generally, a small volume of flashlight can be balanced in about 15 minutes. The long-range effect stays the same.
Color temperature, the current LED is roughly divided into cool white, medium white (positive white), warm white three color temperature. The cool white light has the highest color temperature and poor color rendering, which is rare in the flashlight industry. Zhongbai (Zhengbai) has good color rendering and outstanding brightness, and is widely used. Warm white has the lowest color temperature and better color rendering than medium white (positive white). In the long-range flashlight, the better the color rendering of the LED, the more reflective in the rain, fog and dust environment, the low color temperature LED can still see the object after a long distance. The principle is the same as that of the car. The headlights of the car are basically useless to the foggy environment, while the pale yellow fog lamps can penetrate the fog better.