The ISL6401 adjustable frequency, low power, pulse width modulating (PWM) current mode controller is designed for a wide range of DC-DC conversion applications including boost, flyback, and isolated output configurations. The device is optimized to provide a high performance, low-cost solution for Ringing SLIC (RSLIC) ring and talk power supplies. An integrated inverter allows for easy design of negative voltage regulation circuits with a minimal amount of external components. Internal soft start minimizes start-up stress without any external components. Peak current mode control effectively handles Ring trip transients and provides inherent over-current protection.