For high current applications with wide input ranges, such as the simple drive scheme mentioned above can produce higher calorific value and lower efficiency. The switch driver with constant current output is the first choice to drive high-power led.
The driver is usually used for switching control of the series inductance and led load or parallel capacitance and the power supply voltage on the LED. The inductance or capacitance is used to save the power when the switch is turned on, and then the switch is turned off to provide an electric current for the LED. Unlike linear drives, switching drives can be configured to implement voltage decrement (buck), increment (boost), or both. It is therefore obvious that the switch driver allows the LEDs to work on a wide range of input voltages. In addition to the constant luminous amount of the current adjustment function, they can also reduce the power loss to the minimum. There is no doubt that switching regulators are more efficient than linear regulators. However, compared with linear regulators, switching drives are more expensive and need to be carefully designed for EMI issues. In order to drive the LEDs in the right way, one of the most satisfying performance-price ratios needs to be found.