Invention Application
US20150145439A1 PRE-CHARGING INDUCTOR IN SWITCHING CONVERTER TO ACHIEVE HIGH PWM DIMMING RATIO IN LED DRIVERS
有权
切换转换器中的预充电电感器可实现LED驱动器中的高PWM调光比
- Patent Title: PRE-CHARGING INDUCTOR IN SWITCHING CONVERTER TO ACHIEVE HIGH PWM DIMMING RATIO IN LED DRIVERS
- Patent Title (中): 切换转换器中的预充电电感器可实现LED驱动器中的高PWM调光比
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Application No.: US14264518Application Date: 2014-04-29
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Publication No.: US20150145439A1Publication Date: 2015-05-28
- Inventor: Keith D. Szolusha , Joshua W. Caldwell , Bryan Legates
- Applicant: Linear Technology Corporation
- Applicant Address: US CA Milpitas
- Assignee: Linear Technology Corporation
- Current Assignee: Linear Technology Corporation
- Current Assignee Address: US CA Milpitas
- Main IPC: H05B33/08
- IPC: H05B33/08

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.
Public/Granted literature
- US09072147B2 Pre-charging inductor in switching converter to achieve high PWM dimming ratio in LED drivers Public/Granted day:2015-06-30
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