RT4539 36 V I²C Controlled 6-Channel WLED Driver

Richtek’s RT4539 high-efficiency driver for white LEDs is suitable for single/two cell battery input to drive LED light bars which contain six strings in parallel. The internal current sinks support a maximum of ±2% current mismatching for excellent brightness uniformity in each string of LEDs. To provide enough headroom for current sink operation, the boost controller monitors the minimum voltage of the feedback pins and regulates an optimized output voltage for power efficiency.

The RT4539 has a wide input voltage operating range from 2.7 V to 24 V and contains an I²C interface for controlling the dimming mode, operating frequency, and the LED current. The internal 250 mΩ, 36 V power switch with current-mode control provides overcurrent protection. The switching frequency of the RT4539 is adjustable from 300 kHz to 1.6 MHz, which allows flexibility between efficiency and component size.

The RT4539 is available in the WL-CSP-20B 1.71x2.371 (BSC) with 0.4 mm pitch package.