At present, the light emitting diode driving chips can be divided into: constant voltage driving chips, constant current driving chips, and pulse driving chips. Among them, the constant voltage driver chip is generally our common DC / DC boost chip. The advantage of this solution is that the chip is cheap and does not have complicated peripheral circuits. But only driving the LED with a constant voltage will cause the circuit current to be uncontrollable when driving the output. The consistency of LED brightness cannot be guaranteed.
The constant current driver chip solves the problem of current uncontrollability of the previous constant voltage driver. The current good constant current chips can achieve a constant current accuracy of about 1%, and there is a simple peripheral control interface that can flexibly set the required output current so it is very popular. However, the price of such chips is much higher than that of constant voltage chips and the peripheral circuits are complicated. At the same time, because of the constant output current, the entire chip will discharge faster when the battery is used as a power supply.
At present, the pulse-type driving chip supplies power to the LED lamp with a high-frequency pulse generator output interface. Because the frequency of the pulse signal is very high, the human eye cannot feel the flicker of the LED at all, so this method not only meets the visual needs, but also effectively saves power output on the one hand. And the operating frequency of this type of chip is generally controlled by an external interface. However, the oscillation frequency of this type of chip is currently in the range of 100KHz ~ 500KHz. So the current drive capability is only suitable for low power applications. But I believe that it will be promoted to high-power LED driving in the near future.