The LED drive circuit is the core device of the light-emitting diode lamp and is a circuit used to make the light-emitting diode (LED) bright. With the global advocacy of green lighting and the urgent need for energy saving. More and more lighting products have entered the era of light-emitting diode light sources. As the core device of light-emitting diode lamps, LED driver chips play an increasingly important role.
At present, 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 scheme is that the chip cost is cheap and there is no complicated peripheral circuit. However, only a constant voltage driving the LED will cause uncontrollable circuit current when driving the output, and the consistency of the LED brightness cannot be guaranteed.
The constant current drive chip solves the current uncontrollable problem of the previous constant voltage drive. The current relatively good constant current chip can achieve a constant current accuracy of about 1%, and it has a simple peripheral control interface that can flexibly set the required output current, so it is very popular. But the price of this kind of chip is much higher than that of the constant voltage chip and the peripheral circuit is complicated. At the same time, because of the constant output current, the entire chip discharges 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 perceive the strobe of the LED at all, so this method not only meets the visual needs, but also effectively saves the power output on the one hand. And the operating frequency of this type of chip can generally be controlled by an external interface. However, the current oscillation frequency of this type of chip is generally in the range of 100KHz~500KHz, so the current driving capability is only suitable for low-power applications, and it is believed that it will be upgraded to high-power LED driving occasions in the near future.
