LM27241 - National Semiconductor

LM27241 Synchronous Buck Regulator Controller

The LM27241 is an adjustable 200kHz-500kHz single channel voltage-mode controlled high-speed synchronous buck regulator controller. It is ideally suited for battery powered applications such as laptop and notebook computers. The LM27241 requires only N-channel FETs for both the upper and lower positions of the synchronous stage. It features line feedforward .

Features

line feedforward to improve the response to input transients. At very light loads, the user can choose between the highefficiency Pulse-skip mode or the constant frequency Forced-PWM mode. Lossless current limiting without the use of external sense resistor is made possible by sensing the voltage drop across the bottom FET. A unique adaptive duty cycle clamping technique is incorporated to significantly reduce peak currents under abnormal load conditions. The input voltage range is 5.5V to 28V while the output voltage is adjustable down to 0.6V. Standard supervisory and control features includ.