NCP1308: Controller, Free Running Quasi-Resonant Current Mode

The NCP1308 combines a true current mode modulator and a demagnetization detector to ensure full borderline/Critical Conduction Mode in any load/line conditions and minimum drain voltage switching (Quasi-Resonant operation). Due to its inherent skip cycle capability, the controller enters burst mode as soon as the power demand falls below a predetermined level. As this happens at low peak current, no audible noise can be heard. An internal 10us timer prevents the free-run frequency to exceed a high frequency (therefore below the 150kHz CISPR-22 EMI starting limit), while the skip adjustment capability lets the user select the frequency at which the burst foldback takes place. The Dynamic Self-Supply (DSS) drastically simplifies the transformer design in avoiding the use of an auxiliary winding to supply the NCP1308. This feature is particularly useful in applications where the output voltage varies during operation (e.g. battery chargers). Thanks to its high-voltage technology, the IC is directly connected to the high-voltage DC rail. As a result, the short-circuit trip point is not dependent upon any VCC auxiliary level. The transformer core reset detection is done through an auxiliary winding which, brought via a dedicated pin. If an OVP has been detected on the Vcc pin, the IC permanently latches-off. Finally, the continuous feedback signal monitoring implemented with an over-current fault protection circuitry (OCP) makes the final design rugged and reliable.

Features
  • FreeRunning Borderline/Critical Mode QuasiResonant Operation
  • CurrentMode with Adjustable Skip Cycle Capability
  • Dynamic SelfSupply Type of VCC
  • AutoRecovery Overcurrent Protection
  • Improved UVLO for VCC below 10 VDevice Package Shipping
  • Latching Overvoltage Protection on VCC
  • 500 mA Peak Current Source/Sink Capability
  • Internal 1.0 ms SoftStart
  • Internal 10 us Minimum TOFF
  • Adjustable Skip Level
  • Internal Temperature Shutdown
  • Internal Leading Edge Blanking
  • Direct Optocoupler Connection
  • SPICE Models Available for TRANsient Analysis
  • This is a PbFree Device
Applications
  • ACDC Adapters for Notebooks, etc.
  • Offline Battery Chargers
  • Consumer Electronics (DVD Players, SetTop Boxes, TVs, etc.)
  • Auxiliary Power Supplies (USB, Appliances, TVs, etc.)
Design & Development Tools (2)
Document TitleDocument ID/SizeRevisionRevision Date
Worksheet, QR Power Supply, BasicQR BASIC DWS.XLS (53.0kB)2
Worksheet, QR Power Supply, ComplexQR COMPLEX DWS.XLS (82.0kB)2
Simulation Models (4)
Document TitleDocument ID/SizeRevisionRevision Date
Large signal model for AC analysis (IsSPICE)NCP1207ACIS (235.0kB)0
Large signal model for AC analysis (PSPICE)NCP1207ACPS (38.0kB)0
Simplified freerun model for fast QR simulation (IsSPICE)NCP1207IS (31.0kB)0
Simplified freerun model for fast QR simulation (PSPICE)NCP1207PS (18.0kB)0
Data Sheets (1)
Document TitleDocument ID/SizeRevisionRevision Date
Controller, Free Running Quasi-Resonant Current ModeNCP1308/D (231.0kB)3
Package Drawings (1)
Document TitleDocument ID/SizeRevision
SOIC-8 Narrow Body751-07 (62.6kB)AK
Application Notes (8)
Document TitleDocument ID/SizeRevisionRevision Date
A 30 W Power Supply Operating in A Quasi-Square Wave Resonant ModeAND8129/D (246.0kB)0
A 75 W TV Power Supply Operating in Quasi-square Wave Resonant Mode Using NCP1207 ControllerAND8145/D (326.0kB)0
A Quasi-Resonant SPICE Model Eases Feedback Loop DesignsAND8112/D (205.0kB)1
Determining the Free-Running Frequency for QR SystemsAND8089/D (66.0kB)0
Implementing NCP1207 in QR 24 W AC-DC Converter with Synchronous RectifierAND8127/D (129.0kB)1
Stability Analysis in Multiple Loop SystemsAND8327/D (213.0kB)0
Synchronizing NCP1207 (NCP1377/B, NCP1378)AND8187/D (46.0kB)0
Tips and Tricks to Build Efficient Circuits with NCP1200AND8069/D (139.0kB)1
Order Information
ProductStatusCompliancePackageMSL*ContainerBudgetary Price/Unit
NCP1308DR2GActivePb-free Halide freeSOIC-8751-071Tape and Reel2500$0.56
Specifications
ProductTopologyControl Modefsw Typ (kHz)Stand-by ModeUVLO (V)Short Circuit ProtectionLatchSoft StartVCC Max (V)Drive Cap. (mA)
NCP1308DR2GFlybackCurrent ModeVariableYesYesYesYesYes16500 / 500
Controller, Free Running Quasi-Resonant Current Mode (231.0kB) NCP1308
Worksheet, QR Power Supply, Basic NCP1377
Worksheet, QR Power Supply, Complex NCP1377
Large signal model for AC analysis (IsSPICE) NCP1377
Large signal model for AC analysis (PSPICE) NCP1377
Simplified freerun model for fast QR simulation (IsSPICE) NCP1377
Simplified freerun model for fast QR simulation (PSPICE) NCP1377
A 30 W Power Supply Operating in A Quasi-Square Wave Resonant Mode NCP1308
A 75 W TV Power Supply Operating in Quasi-square Wave Resonant Mode Using NCP1207 Controller NCP1308
A Quasi-Resonant SPICE Model Eases Feedback Loop Designs NCP1377
Determining the Free-Running Frequency for QR Systems NCP1377
Implementing NCP1207 in QR 24 W AC-DC Converter with Synchronous Rectifier NCP1308
Stability Analysis in Multiple Loop Systems NCP1055
Synchronizing NCP1207 (NCP1377/B, NCP1378) NCP1377
Tips and Tricks to Build Efficient Circuits with NCP1200 NCP1308
SOIC-8 Narrow Body CM1216
NCP1308