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
