The MC44608 is a high performance voltage mode controller designed for off−line converters. This high voltage circuit that integrates the startup current source and the oscillator capacitor, requires few external components while offering a high flexibility and reliability.

The device also features a very high efficiency standby management consisting of an effective Pulsed Mode operation. This technique enables the reduction of the standby power consumption to approximately 1.0 W while delivering 300 mW in a 150 W SMPS.

General Features

• Integrated Startup Current Source

• Lossless Off−Line Startup

• Direct Off−Line Operation

• Fast Startup

• Flexibility

• Duty Cycle Control

• Undervoltage Lockout with Hysteresis

• On Chip Oscillator Switching Frequency 40 or 75

• Secondary Control with Few External Components

• Pb−Free Packages are Available*

Protections

• Maximum Duty Cycle Limitation

• Cycle by Cycle Current Limitation

• Demagnetization (Zero Current Detection) Protection

• “Over VCC Protection” Against Open Loop

• Programmable Low Inertia Over Voltage Protection Against Open Loop

• Internal Thermal Protection

SMPS Controller

• Pulsed Mode Techniques for a Very High Efficiency Low Power Mode

• Lossless Startup

• Low dV/dT for Low EMI Radiations