The XL1509 is a 150KHz fixed frequency PWMbuck(step-down) DC/DC converter,capable of driving a 3A load with high efficiency, low ripple and excellent line and load regulation. Requiring a minimum number of external components, the regulator is simple to use and include internal frequency compensation and a ixed-frequency oscillator.

The PWM control circuit is able to adjust the  duty ratio linearly from 0 to 100%. An enable  function, an over current protection function is built inside. When second current limit  function happens, the operation frequency  will be reduced from 150KHz to 50KHz. An  internal compensation block is built in to  minimize external component count.