iWatt debuts industry’s first driver to power 32 strings of LEDs in ultra-thin LED TVs

LOS GATOS, USA: iWatt, Inc., a developer of energy-efficient digital power supply control integrated circuits (ICs) used in leading-edge power supplies, expanded its family of DC/DC LED backlight drivers with its iW7032 which can power up to 32 parallel strings of LEDs.

Like its iW7040 sibling, which powers up to 64 parallel strings of LEDs, the iW7032 is a mixed-signal IC that features iWatt’s digital adaptive switching technology with integrated MOSFETs. Adaptive switching reduces thermal overhead and power consumption, while the integrated MOSFETs reduce component count, form factors and costs for dynamic backlighting.

The 32-channel iW7032 targets mainstream direct or segment-edge-dimmed TVs, while iWatt’s existing 64-channel iW7040 is suited for high-end, direct-dimmed TVs. Both drivers are designed to enable real cost savings in dynamic backlighting, as well as easy integration into ultra-thin LED TVs.

With high voltage support (up to 56V) and adaptive switching to overcome thermal problems, the iW7032 is capable of driving more parallel strings of LEDs from a single IC than existing solutions, reducing component count for TV manufacturers.

Typical ICs can drive eight, 12 or at most 16 strings of LEDs, while the iW7032 can drive up to 32 parallel strings, numbering 15 LEDs per string, to power 480 total LEDs from one IC. iWatt’s high-voltage support also saves the cost of any additional protection MOSFETs required by ICs with lower string voltages.

iWatt’s proprietary digital adaptive switching technology solves the thermal problems of driving a large number of parallel strings of LEDs, where a significant amount of wasted power typically heats the inside of the TV and increases the chance of thermal-stress-related LED failures.

iWatt’s adaptive switching technology senses the mismatch of the varying forward voltages (Vf) of the multiple strings of LEDs and adjusts appropriately for each string. This reduces the wasted power by up to 90 percent (iWatt projects it saves 2-5W per IC), minimizes the heat generated, and enables a single iWatt IC to drive many multiples of LED strings.

The iW7032 features an integrated MOSFET for each string of LEDs to save component count and reduce form factors for easy integration into ultra-thin LED TVs. The company projects this can reduce driver printed-circuit-board (PCB) form factors by up to 50% compared to solutions relying on external MOSFETS.

With the ability to drive more LEDs with fewer ICs, and by integrating the MOSFETs, iWatt projects LED TV manufacturers can save $1 to $3 in bill-of-material (BOM) costs for each iW7032 used. A typical 46” direct-lit LED TV might use two to four iW7032 drivers, saving the manufacturer up to $12.