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WLED driver integrates a 48-V MOSFET to provide a complete backlighting solution

June 30, 2010 // Paul Buckley

WLED driver integrates a 48-V MOSFET to provide a complete backlighting solution

Maxim Integrated Products has introduced a six-string WLED driver that provides a complete backlighting solution for notebooks and netbooks. The high-performance step-up controller integrates a 48 V MOSFET capable of driving up to 13 LEDs/string.


The integration reduces BOM cost and saves board space by eliminating an external MOSFET. The step-up controller frequency can be programmed from 250 kHz to 1MHz, allowing flexibility in selecting external components. The MAX17127 features a wide input-voltage range (5 V to 26 V), making it well suited for both netbooks that use a 2- to 3-cell Li+ battery and notebooks that use a larger battery.

The current in each string can be programmed from 10 mA to 30 mA using an external resistor, which helps in setting the appropriate brightness level. Meanwhile, better than ±2 percent accurate current matching between strings ensures even LED brightness. The MAX17127 operates in a direct-dimming mode with a dimming frequency ranging from 100 Hz to 25 kHz. The LED current is directly controlled by the external dimming signal's frequency and duty cycle. The wide dimming range eliminates the audible noise issues usually encountered in WLED drivers. A low feedback voltage at each LED string helps reduce power loss and improve efficiency.

The MAX17127 offers multiple features to protect the controller from faults, including  overcurrent, overtemperature, and  open-/short-string conditions. Additionally, the step-up controller has cycle-by-cycle current limiting and soft-start capability to control  inrush current.

Availability and Pricing

The MAX17127 is available in a 4 mm x 4 mm, 20-pin TQFN package and operates over the -40 to +85 degrees Celsius extended temperature range. Prices start at 0.73 US Dollars (1000-up, FOB USA).

Datasheet: MAX17127

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