Because many people do not understand the problem, they always have to go to the dimming circuit to find the problem, which is futile. Using step-down constant current source problems will be less, because if the original power supply voltage is higher than the load voltage, when the LED brightness is to low-key, the load voltage is reduced, so you still need step-down constant current source. But if the forward current is very low, the load voltage of the LED also becomes very low, then the buck ratio is very large, it may be beyond the normal working range of the buck type constant current source, and will make it unable to work and produce flicker. LED working at low brightness for a long time may reduce the efficiency of the step-down constant current source and increase the temperature rise, so it can not work.

Common-Cathode CC 3203AW 7-Segment digit 3203AW LED Common-Anode CA 3203BW Display 3203BW 0.30 inch
0.32 inch 3231AS LED Common-Cathode CC 3231AS 7-Segment digit 3231BS Display 3231BS Common-Anode CA

LED load voltage must be lower
LED brightness low-key with reduced voltage
Different LEDs with current and output curves
The working ratio change LED brightness
LED heat dissipation technology
LED lamp work is stable
Heat management with high brightness LED
Heat dissipation for highlight LED
LED device to extract heat from P-N junction
LED Lamp surface radiation heat treatment