Maxim MAX17127 six-string WLED driver

Maxim has introduced the MAX17127, a six-string WLED driver that provides backlighting for notebooks and netbooks.

The step-up controller integrates a 48 V MOSFET capable of driving up to 13 LEDs/string. This 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 1 MHz, and the device features a wide input-voltage range (5 to 26 V), making it suitable for both netbooks that use a two- to three-cell Li+ battery and notebooks that use a larger battery.

The current in each string can be programmed from 10 to 30 mA using an external resistor, which helps in setting the appropriate brightness level. Better than ±2% accurate current matching between strings ensures even LED brightness. The driver 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 device 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.