The CAT4106 LED driver from On Semiconductor includes an integrated, high-power dc-dc boost converter and on-chip diagnostics to maximize efficiency in larger, general-purpose LCD panel backlighting applications. This multi-channel boost device can drive as many as 40 white LEDs, or four strings of 10 LEDs with up to 36 V per string, for a total of 6 W of LED output power. Additionally, this driver enables designers to maximize backlighting efficiency and reduce space via its built-in diagnostics functions, which automatically adjust the output voltage to drive the highest forward-voltage string with the minimum head-room voltage, according to On Semi.
The on-chip diagnostic circuit allows designers to set the minimum and maximum voltage limits for the acceptable range of operation for LED strings through external programming resistors. Any channel that doesn’t regulate within the set range of Open Circuit or Short Circuit LED will be detected and flagged on the FAULT logic output (active-low, open-drain). The device also provides thermal shutdown and overvoltage protection. It features low-dropout LED channels of 500 mW at 175 mA and a high-frequency pulse-width modulation (PWM) interface, which supports multiple frequencies up to 2 kHz, providing precise, high-resolution dimming control while the device remains fully biased.
The CAT4106 is available in a 4- by 4-mm, 16-lead thin quad flat no-lead (TQFN) package and in a 16-lead thin-shrink small-outline package (TSSOP) with an exposed thermal pad for enhanced power dissipation. It costs $1.06 each in 10,000-unit quantities. Samples and evaluation boards are available now. Projected lead time for production quantities is six to eight weeks ARO.