ML4810

May 1997 ML4810*, ML4811** High Frequency Power Supply Controller GENERAL DESCRIPTION The ML4810 and ML4811 High Frequency PWM Controllers are optimized for use in Switch Mode Power Supply designs running at frequencies to 1MHz. The ML4810/11 contain a unique overload protection circuit which helps to limit stress on the output devices and reliably performs a soft-start reset. These controllers are designed to work in either voltage or current mode and provide for input voltage feed forward. A 1.1V threshold current limit comparator provides a cycle-by-cycle current limit. An integrating circuit “counts” the number of times the 1.1V limit was reached. A soft-start cycle is initiated if the cycle-by-cycle current limit is repeatedly activated. A reset delay function is provided on the ML4811. These controllers are similar to the UC1825 controller, however these controllers include many features not found on the 1825. These features are set in Italics. FEATURES s s s s s s s s s s s Integrating Soft Start Reset High current (2A peak) dual totem pole outputs Practical operation to 1MHz (fOSC) 5.1V ± 2% trimmed bandgap reference Under voltage lockout with 7V hysteresis Soft Start Reset Delay (ML4811) Oscillator synchronization function (ML4811) Soft Start latch ensures full soft start cycle Outputs pull low for undervoltage lockout Accurately controlled oscillator ramp discharge current All timing currents “slaved” to RT for precise control * This part is End of Life as of Aug...