GENERAL DESCRIPTION

The ML4819 is a complete boost mode Power factor Controller (PFC) which also contains a PWM controller. The PFC circuit is similar to the ML4812 while the PWM controller can be used for current or voltage mode control for a second stage converter. Since the PWM and PFC circuits share the same oscillator, synchronization of the two stages is inherent. The outputs of the controller IC provide high current (>1A peak) and high slew rate to quickly charge and discharge MOSFET gates. Special care has been taken in the design of the ML4819 to increase system noise immunity.

FEATURES

■ Two 1A peak current totem-pole output drivers

■ Precision buffered 5V reference (±1)

■ Large oscillator amplitude for better noise immunity

■ Precision duty cycle limit for PWM section

■ Current input gain modulator improves noise immunity

■ Programmable Ramp Compensation circuit

■ Over-Voltage comparator helps prevent output “runaway”

■ Wide common mode range in current sense compensators for better noise immunity

■ Under-Voltage Lockout circuit with 6V hysteresis