Fairchild launches LED driver for dimmable retrofit lamp applications

Feb. 9, 2015
Active-dimmer-driver technology eliminates flicker and Fairchild says the IC is compatible with more than 90% of the dimmers on the market.

Active-dimmer-driver technology eliminates flicker and Fairchild says that the IC is compatible with more than 90% of the dimmers on the market.

Fairchild has announced the FL7734 LED driver IC intended for usage in retrofit lamp design ranging from candle lamps to A lamps to PAR lamps. The single-stage design offers compatibility with more than 90% of phase-cut dimmers on the market, according to the company, and also supports a programmable dimming curve allowing the solid-state lighting (SSL) product developer to more closely mimic the operation of legacy bulbs.

Indeed, dimming support is the major benefit of the new LED driver IC that Fairchild is promoting. "The FL7734 driver simplifies LED light designs with broad dimmer compatibility," said James Lee, technical marketing manager at Fairchild. "LED bulb and phase-cut dimmer suppliers are different, so a good phase-cut dimmable bulb has to operate well with many different dimmers. We developed the FL7734 with this in mind."

Of course, Fairchild is certainly not the first driver IC company to stake claims to broad dimmer compatibility. Marvell, for instance, has said that some of its LED driver ICs can recognize dimmer characteristics and adapt for the dimmer in a given application. Dialog's iWatt business unit has made similar claims with its LED driver ICs, including the single-stage iW3606/08. For more background on the dimmer-compatibility challenge, see our feature article on the topic.

The FL7734 is a flyback or buck-boost controller designed for use in pulsewidth modulation (PWM) of current to an LED string. Like other single-stage LED driver ICs, the new Fairchild product attempts to minimize the bill of materials in terms of the discrete components required for the complete driver circuit — a requirement in cost-sensitive LED retrofit lamps. Specifically, Fairchild integrated primary-side-regulation technology to minimize the component count.

Back to dimming, Fairchild describes the implementation as active dimming control. Moreover, the programmable dimming curve support enables the product developer to configure a design that matches dimmer settings to specific light output levels. Specifically, the IC allows the developer to correlate maximum and minimum phase-angle detection to be matched with current output levels.

Fairchild said that the new LED driver IC can support lamp or luminaire designs ranging from 5W to 60W. It supports current control within 1%. Fairchild has added open-LED, short-LED, and over-temperature protection functions to ensure reliable SSL products. Indeed, those features enable products based on the IC to meet NEMA (National Electrical Manufacturers Association) 7A-2013 and US Environmental Protections Association (EPA) Energy Star guidelines.