Synchronizing Current Mode PWM for Subscriber Line Interface Circuits (SLICs)

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.

Features
• Positive and Negative Output Regulation
• Starting Supply Current . . . . . . . . . . . . . . . . . 100µA (typ.)
• Quiescent Current . . . . . . . . . . . . . . . . . . . . . . 55µA (typ.)
• Output Frequency Range. . . . . . . . . . . . 50kHz to 600kHz
• External Clock Synchronization
• Fast Transient Response with Peak Current Mode Control
• Internal Soft-Start
• Drives N-Channel MOSFET
• Logic Level Shutdown
• Leading Edge Blanking
• 1% Tolerance Voltage Reference Over Line and Temperature

Applications
• VoIP/VoDSL Ringer and Off-Hook Voltage Generators
• Multi-Output Flyback Supplies
• Cable and DSL Modems
• Set-Top Boxes
• Wireless Local Loops
• LMDH and FTTH Supplies
• Boost Regulators
• Routers