Macbook Controller IC Chip - NSC LP8550 Backlight LED Driver IC U7701 / U9701

The LP8550 is a white-LED driver with intergrated boost converter, It has sic adjustable current sinks which can be controlled by PWM input or with compatible serial interface. The boost converter has adaptive ouput voltage control based on the LED driver voltages. This feature minimizes the power consumption by adjusting the voltage to lowest sufficient level in all condition. LED outputs have 8-bit current resolution and up to 13-bit PWM resolution with additional 1- to 3-bit dithering to achieve smooth and precise brightness control. Proprietary Phase Shift PWM control is used for LED outputs to reduce peak current from the boost converter, thes making the boost capacitors smaller. The Phase Shifting scheme also eliminates audible. Automatic PWM dimming at lower brightness values and current dimming at higher brightness values can be used to improve the optical efficiency. Internal EEPROM is used for storing the configuration data. The makes it possible to have minimum external component count and make the solution very small. The LP8550 has safety features which make it possible to detect LED ouputs with open or short fault ---- low input voltage and boost overcurrent conditions are monotored, and chip is turned off in case of these events. Thermal de-rating function prevents overheating of the device by reducing backlight brightness when se temperature has been reached.

Compatible boards 820-3023 820-00165 820-3209 820-3437 820-3024 820-3208 820-3435 820-00164 820-3330 820-2915 820-3115 820-2936

Applicable Models (Logic Board No.)

A1466 - 820-3437, 820-00165, 820-3209

A1465 820-3208, 820-3435, 820-00164

A1398 820-3332

A1370 820-3024

A1369 820-3203

A1286 820-2915, 820-3330

A1278 820-2936 , 820-3115