PWM Series Dimming for Slow-Dynamics HPF LED Drivers: the High-Frequency Approach

This paper deals with the capability of pulse width modulation (PWM) dimming operation added to the high-power factor-integrated buck-flyback converter (IBFC), which was developed in previous works for LED lighting applications. First, the two main dimming techniques will be introduced, namely, anal...

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Bibliographic Details
Published in:IEEE transactions on industrial electronics (1982) 2012-04, Vol.59 (4), p.1717-1727
Main Authors: Gacio, D., Alonso, J. M., Garcia, J., Campa, L., Crespo, M. J., Rico-Secades, M.
Format: Article
Language:English
Subjects:
Converters
Dimming
Drivers
Frequency conversion
Harmonic distortion
Illumination
Industrial power systems
Light emitting diodes
light-emitting diodes (LEDs)
Lighting
lighting control
power electronics
Proposals
Pulse duration modulation
Pulse width modulation
Studies
Topology
Voltage measurement
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Summary:This paper deals with the capability of pulse width modulation (PWM) dimming operation added to the high-power factor-integrated buck-flyback converter (IBFC), which was developed in previous works for LED lighting applications. First, the two main dimming techniques will be introduced, namely, analog dimming and PWM dimming. Then, the three main PWM dimming schemes found in the literature, that is, enable dimming, series dimming, and parallel dimming, will be briefly discussed. Afterwards, the IBFC topology will be tested performing both analog and enable dimming. In addition, a new proposal is introduced: the high-frequency series PWM dimming technique, which overcomes all the challenges faced when developing PWM dimming capabilities in low slew-rate constant-current fixed-frequency-controlled converters and offers all the advantages of PWM dimming over analog dimming while maintaining good efficiency. The proposed dimming-technique control loop, as well as the laboratory tests, will be presented, discussed, and compared to analog dimming and PWM dimming, showing satisfactory results in terms of dimming ratio, input current total harmonic distortion (THD I ), and power factor.
ISSN:0278-0046
1557-9948
DOI:10.1109/TIE.2011.2130503