Power Supply IC Combines PWM And PFC Capabilities

Combining both power-factor correction (PFC) and pulse-width modulation (PWM) functions, the ML4803 power supply chip is said to reduce the cost of building a power supply by about $0.40. It does so by eliminating six external components and by allowing the use of a less costly PFC capacitor. Typical applications for the IC are supplies rated at from 70W to 1000W.The IC contains circuits required to design universal-input power supplies that automatically adapt to the voltage and frequency of line power worldwide. Its PFC stage achieves a high power factor rating and reduces noise and distortion injected into the power line. A redundant overvoltage comparator protects the PFC section in the event of a sudden decrease in load or a fault condition. Efficiency of power supplies is increased by a leading-edge, trailing-edge circuit that reduces losses in filter capacitors.