Onsemi NCP1612

Description

The NCP1612 is designed to drive PFC boost stages based on an innovative Current Controlled Frequency Fold−back (CCFF) method. In this mode, the circuit classically operates in Critical conduction Mode (CrM) when the inductor current exceeds a programmable value. When the current is below this preset level, the NCP1612 linearly decays the frequency down to about 20 kHz when the current is null. CCFF maximizes the efficiency at both nominal and light load. In particular, the stand−by losses are reduced to aminimum.

Like in FCCrM controllers, internal circuitry allows near−unity power factor even when the switching frequency is reduced. Housed in a SO−8 package, the circuit also incorporates the features necessary for robust and compact PFC stages, with few external components.

Features

• Near−Unity Power Factor
• Critical Conduction Mode (CrM)
• Current Controlled Frequency Fold−back (CCFF): Low FrequencyOperation is Forced at Low Current Levels
• On−time Modulation to Maintain a Proper Current Shaping in CCFFMode
• Skip Mode Near the Line Zero Crossing
• Fast Line / Load Transient Compensation (Dynamic ResponseEnhancer)
• Valley Turn on
• High Drive Capability: −500 mA / +800 mA
• VCC Range: from 9.5 V to 35 V
• Low Start−up Consumption
• A Version: Low VCC Start−up Level (10.5 V), B Version: High VCCStart−up level (17.0 V)
• Line Range Detection
• Configurable for Low Harmonic Content across WideLine/Load Range
• EN61000−3−2 Class C Compliant across Wide LoadRange for Dimmable Light Ballasts
• This is a Pb−Free Device
• Low Duty−Cycle Operation if the Bypass Diode isShorted
• Open Ground Pin Fault Monitoring
• Saturated Inductor Protection
• Detailed Safety Testing Analysis (Refer to ApplicationNote AND9064/D)
• Non−latching, Over−Voltage Protection
• Brown−Out Detection
• Soft−Start for Smooth Start−up Operation (A version)
• Over Current Limitation
• Disable Protection if the Feedback Pin is Not Connected
• Thermal Shutdown

Typical applications

• All Off−Line Applications Requiring Power Factor Correction
• PC Power Supplies

More information

• Datasheet
• IC product information