The new NCP1901 meets the efficiency standards, like ENERGY STAR v2.0 for external power supplies, California Energy Commission (CEC), European Code of Conduct and the China Standard Certification Center (CSC).
The advantage of the new NCP1901 is the new combination of a PFC controller operating in critical conduction mode (CRM) and the resonant half-bridge controller. The overall voltage regulation is maintained by adjusting PFC output voltage. This enables a fixed frequency resonant controller to be used, reducing the transformer size and maximizing efficiency.
The resonant controller has an integrated half-bridge driver that is rated at 600 volts (V), abolishing the need for an external driver or gate drive transformer. A 600 V startup circuit enables direct connection to the bulk capacitor, improving efficiency at light loads through the omission of startup resistors.
Integrating both controllers in a single package ensures the correct sequencing and operation between PFC and half-bridge stages. This enables robust power supplies with key protection features, incorporating open feedback loop, and PFC overvoltage and undervoltage protection, to be designed quickly while still maintaining design flexibility.
“The NCP1901 provides a best in class solution for off-line adapters,” stated Bill Schromm, senior vice president and general manager of ON Semiconductor’s Computing and Consumer Group. “The integration level achieved translates directly into a smaller form factor. When combined with the higher efficiency of the resonant controller, in either full load or no-load conditions, additional size and cost can be saved through reduction of components and heatsinks.”
