The NCP1605 is a controller that exhibits near−unity power factor while operating in fixed frequency, Discontinuous Conduction Mode (DCM) or in Critical Conduction Mode (CRM).
Housed in a SOIC−16 package, the circuit incorporates all the features necessary for building robust and compact PFC stages, with a minimum of external components. In addition, it integrates the skip cycle capability to lower the standby losses to a minimum.

General Features
• Near−Unity Power Factor
• Fixed Frequency, Discontinuous Conduction Mode Operation
• Critical Conduction Mode Achievable in Most Stressful Conditions
• Lossless High Voltage Current Source for Startup
• Soft Skip Cycle for Low Power Standby Mode
• Switching Frequency up to 250 kHz
• Synchronization Capability
• Fast Line / Load Transient Compensation
• Valley Turn On
• High Drive Capability: −500 mA / +800 mA
• Signal to Indicate that the PFC is Ready for Operation (“pfcOK” Pin)
• VCC range: from 10 V to 20 V
• Follower Boost Operation
• Two VCC Turn−On Threshold Options: 15 V for NCP1605 & NCP1605B; 10.5 V for NCP1605A
• These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS Compliant

Safety Features
• Output Under and Overvoltage Protection
• Brown−Out Detection
• Soft−Start for Smooth Startup Operation
• Overcurrent Limitation
• Zero Current Detection Protecting the PFC stage from Inrush Currents
• Thermal Shutdown
• Latched Off Capability

Typical Applications
• PC Power Supplies
• All Off Line Appliances Requiring Power Factor Correction