The Overview of Led Driver Power Supply
Switching regulators are energy efficient and offer excellent brightness control. The linear regulator structure is simple, easy to design, provides steady current and overcurrent protection, and has no electromagnetic compatibility (EMC) problems.
In low-current LED applications, the resistive driver, although low in cost and simple in structure, has a low forward current under low voltage conditions, which causes LED brightness to be insufficient and under transient conditions such as load dump. The LED may be damaged; and the resistor is an energy consuming component, and the overall solution is less energy efficient.
For example, in LED lighting applications using DC-DC power supplies, the LED driving methods that can be used are resistance type, linear regulators, and switching regulators.
In the resistive drive mode, the forward current of the LED can be controlled by adjusting the current sense resistor in series with the LED. This drive mode is easy to design, low in cost, and has no electromagnetic compatibility (EMC) problem. The disadvantage is that it depends on the voltage and needs to be filtered. (binning) LED with low energy efficiency.
Linear regulators are also easy to design and have no EMC issues. They also support current regulation and fold back, and provide an external current set point. The power dissipation problem is insufficient, and the input voltage is always higher than the forward voltage. Voltage, and energy efficiency is not high. The switching regulator continuously controls the opening and closing of the switch (FET) through the PWM control module to control the flow of current.