Power Electronics

Offline LED Driver for Retrofit Lamps

Maxim Integrated Products (introduces the MAX16841, an offline LED driver that provides flicker-free dimming from maximum light intensity down to zero intensity with both leading-edge (triac) and trailing-edge (transistor) dimmers. Constant frequency control optimizes efficiency at both low- and high-AC line voltages. With a wide 90VAC to 265VAC input range, the MAX16841 is a universal solution for Japanese, Chinese, U.S., and European dimmer models. It allows seamless replacement of incandescent and halogen lamps, thus eliminating compatibility issues with preinstalled dimmers. The MAX16841 prolongs the life of the LED lamps because it can operate without electrolytic capacitors. Eliminating those capacitors also saves space and cost. This LED driver is ideal for retrofit dimmable LED lamps and universal LED bulbs in industrial, commercial, and residential lighting applications.

To retrofit traditional lamps seamlessly, LED lamps must be compatible with both leading-edge and trailing-edge dimmers. These dimmers are typically designed for the perfectly resistive loads of traditional halogen and incandescent lamps. LED drivers, however, are very nonlinear and not ideally compatible with the purely resistive loads of the dimmers. As a consequence, when LED lamps are inserted into an existing electrical infrastructure with dimmers, the LED lamps generally flicker, do not dim, and in some cases do not turn on at all.

The MAX16841 solves this dimming problem with a unique, proprietary approach to control the lamp's input current. By actively shaping the input current, the driver ensures flicker-free operation with most electronic transformers and dimmers. Now LED lamp designers can reliably create drop-in replacements for halogen and incandescent lighting with dimming down to zero light intensity and without the need for costly infrastructural upgrades.

The MAX16841 can be designed in without electrolytic capacitors. This extends the lifetime of the LED lamp, since electrolytic capacitors are usually the first component to fail in the driver circuit. If electrolytic capacitors are present from an existing design, the MAX16841 lets the lamp continue to operate even when those capacitors fail.

The MAX16841 is fully specified over the -40 °C +125 °C temperature range. It is available in an 8-pin SOIC package. Prices start at $1.35 (1000-up, FOB USA).

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