LED drive power generally refers to AC / DC converter, whose core part is LED driver; LED driver belongs to DC / DC converter, which can be used alone or constitute LED drive power. This is the main difference between the two. The similarities between the two are constituted by LED driver chips.
In switching LED drivers with output current feedback, feedback compensation is generally required to stabilize the converter and adjust the current to achieve the desired current value. The transient response performance of these feedback schemes is limited and cannot meet the fast on / off transient response required by the PWM brightness adjustment of LEDs. However, the converter described herein does not require any feedback compensation. The only feedback used in this control scheme is to obtain the peak current through the MOSFET through the sense resistor. Because the converter stores the required energy every cycle, it can respond instantly to transients. So it can easily work with PWM brightness adjustment scheme.
The buck-boost converter is an effective solution for low DC voltage input LED drivers. It can drive LED strings regardless of whether the output voltage is higher or lower than the input voltage. In addition, small and inexpensive additional circuits can be added to the converter to overcome problems with load regulation and no-load conditions. The converter is easy to implement and does not require feedback compensation during peak current mode control. Its open-loop nature also makes it ideal for applications that require PWM dimming