Invention Grant
US09072147B2 Pre-charging inductor in switching converter to achieve high PWM dimming ratio in LED drivers 有权
在开关转换器中预充电电感,以实现LED驱动器中的高PWM调光比

Pre-charging inductor in switching converter to achieve high PWM dimming ratio in LED drivers
Abstract:
In a method for controlling a current regulator for dimming an LED load, a dimming signal has a duty cycle that controls the LED ON-time and LED OFF time at a fixed frequency. The regulator is controlled by the dimming signal to only supply current to the LED load during the LED ON-time. The regulator includes an inductor. The inductor current at the end of an ON-time is detected and its value is stored. During the OFF-time, the inductor is pre-charged to the current level matching the stored value, while the regulator's feedback loop is frozen during the OFF-time to not change its feedback control signal. Upon the next ON-time, the regulator begins supplying current to the LED load with the pre-charged inductor current, so there is no initial decrease in the delivered LED current. Therefore, the current pulse magnitudes are constant even with very low duty cycles.
Information query
Patent Agency Ranking
0/0