ANPEC IC Integrated Circuit Chip APW7228B

The APW7228B is a high efficiency driver for 4 channels of LEDs. It contains an adjustable-frequency currentmode PWM step-up controller, a 5V linear regulator, dimming control circuit and eight regulated current source circuit. The APW7228B is capable of driving typically 68 (4x17) pieces of 3.5V/160mA LEDs. It contains 4 channels of voltage controlled current sources with typical currents matching of +1%, which compensate for the non-uniformity effect of forward voltages variance in the LED stacks. To minimize the voltage headroom and power loss in the typical multi-strings operation, the APW7228B features a dynamic headroom control that monitors the highest LED forward voltage string and uses its feedback signal for output regulation. The APW7228B features extensive protection functions that include LED strings open and short circuit detections, Output Over-Voltage Protection (OVP) and Over-Temperature Protection (OTP). The APW7228B is available in TSSOP-16P, SOP-16, DIP16 and QFN4x4-16A package.