EET

LED Constant Current Source Boosts Component Reliability

A buck-mode LED driver IC uses hysteretic current control and high-side current sensing.

The HV9918 is a buck-mode LED driver IC with hysteretic current control and high-side current sensing. It targets a variety of solid-state lighting applications, such as low-voltage industrial and architectural LED lighting, signage or decorative lighting, indicator or emergency lighting, as well as a general purpose constant current source.

The hysteretic control function of the HV9918 maintains a constant output current to the LED string at all times, regardless of input voltage fluctuations. LEDs are proven to be far more reliable and long lasting when driven by a constant current than by a direct voltage source. The chip drives loads of up to 1.0A at over 90% efficiency with +/-5% current accuracy from input voltages of 4.5 to 40V. The IC also features an embedded FET for cost and parts count reduction in solid-state lighting applications.

"Supertex's HV9918 provides fast transient load response and eliminates the need for feedback-loop compensation," states Ahmed Masood, Vice President of Marketing for Supertex. "With its built-in switching FET, this device reduces overall system cost and board space while delivering accurate current control for LED lighting applications."

The HV9918 is available in an 8-Lead DFN package (HV9918K7-G). The part is Green and RoHS compliant. Samples are available from stock. Lead-time for production quantities is 4-6 weeks ARO. Pricing is US$0.68 for the HV9918K7-G in 1K quantities.

http://www.supertex.com/

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