iWatt single-stage SSL LED drivers deliver exceptional bulb dimming performance

USA: iWatt Inc., a leading provider of digital-centric power management integrated circuits (ICs), launched its latest single-stage, solid state lighting (SSL) LED drivers to address cost, performance and lifetime issues in dimmable bulb applications.

Following the introduction of its single-stage LED driver for non-dimmable incandescent bulb replacement applications earlier this year, iWatt is debuting the iW3606 (8W output power) and iW3608 (15W output power), giving LED bulb manufacturers an alternative approach to significantly lower cost and tackle the lifetime and performance issues in dimmable applications.

Both new LED drivers allow SSL designers to reduce their bill of materials (BOM) cost by 20-40 percent compared to competitive solutions. The iW3606 and iW3608 incorporate iWatt’s patented, configurable over-temperature protection (OTP) and derating functionality to provide predictability and reliability of bulb operating life and offer what the company believes is the industry’s lowest pop-on current, less than 5 percent of light output.

Designed for all retrofit bulbs, including candle and GU10 lamp replacements used in existing phase-cut dimmer installations, the iW3606 and iW3608 manage the key issues that could impact consumer adoption of SSL lighting, including poor dimming performance (pop-on, popcorning, dead travel, drop-out, flicker), short bulb lifetime or failure, and high cost.

Both drivers meet or exceed global regulations for power quality and efficiency with a high power factor (PF) of less than 0.92, low total harmonic distortion (THD) of less than 20 percent, and high efficiency. The iW3606 and iW3608 have already been designed in to the next-generation of dimmable SSL bulb products from key iWatt customers.

The on-chip over-temperature protection (OTP) and derating feature of the iW3606 and iW3608 addresses the thermal issues caused by the high and unpredictable operating temperatures in dimmable SSL applications. The lifetime of many of the components in the LED driver circuit, especially electrolytic capacitors, degrades as temperatures increase, potentially reducing overall bulb lifetime to less than 2,000 hours, well under the 30,000 to 50,000 hours expected for SSL bulbs.

iWatt’s OTP derating monitors the temperature inside the sealed SSL bulb and when thermal conditions reach a point set by the system designer, the LED drivers automatically reduce the current drive to the LEDs, lowering the power dissipation and resulting in cooler overall operation. This helps prevent exceeding the temperature rating of the electrolytic capacitors in the system, helping to ensure a predictable and safer bulb operating life.