Adaptive LED current ripple suppressor enables HPF and flicker-free pro LED lighting

24-06-2019 | Diodes Inc | Lighting Technologies

Diodes Incorporated has released the AL5822 LED current ripple suppressor, which offers high levels of ripple suppression while maintaining high power factor for industrial and commercial lighting applications.


It is now mandatory to satisfy regulatory demands to suppress low-frequency ripple (100Hz to 120Hz) in LED lighting applications in many markets, enforced through standards such as the California Energy Commission Title 24. The device provides a high level of ripple current suppression in single-stage, high power LED installations, even when triac or PWM dimming techniques are being used to modify the light level. This assures there is no sign of flicker or strobing across the complete dimming range, while still keeping a high power factor.


The device has been created and tested to comply with the Title 24 building code demand of less than 30% flicker. The results show that the device suppresses over 97% of ripple while still delivering a power factor of greater than 0.9.


By monitoring the current flowing through the LEDs, the suppressor compensates for ripple by modifying the drive voltage for the external MOSFET. This control loop keeps the MOSFET working in the saturation region to provide a constant current.


With support for various pre-stage circuits, the device can work with several drivers, such as the AL1665 single stage PFC flyback buck/boost controller, also from the company. The integrated features of the device eliminate the requirement for magnetic discrete components, minimising the overall bill of materials.


The device runs over an input voltage range of 24VAC to 305VAC. Safety features include LED short-circuit, over-temperature, and over-current protection.

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