NCP1377: Controller, Free Running Quasi-Resonant Current Mode

The NCP1377 combines a true current mode modulator and a demagnetization detector which ensures full borderline / critical Conduction Mode in any load/line conditions together with 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. For NCP1377, an internal 8.0µs timer prevents the free-run frequency to exceed 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. For NCP1377B, the internal timer duration is reduced to 3.0µs to allow operation at higher frequencies.The transformer core reset detection is done through an auxiliary winding which, brought via a dedicated pin, also enables fast Over-Voltage Protection (OVP). Once an OVP has been detected, the IC permanently latches-off. The 1377 features a sampling time of 4.5µs whereas it is 1.5µs for the B version.The NCP1377 also features an efficient protective circuitries which, in presence of an overcurrent condition, disables the output pulses and enters a safe burst mode, trying to re-start. Once the default has gone, the device auto-recovers. Finally an internal 1ms soft-start eliminates the traditional startup stress.

Features
  • Free-running borderline / critical mode quasi-resonant operation
  • Latched Over Voltage Protection
  • Auto-recovery short-circuit protection via UVLO crossover
  • External latch triggering, e.g. via over-temperature signal
  • Current-Mode with adjustable Skip-cycle capability
  • Internal 1ms soft-start
  • Internal temperature shutdown
  • Internal Leading Edge Blanking
  • 500mA peak current source/sink capability
  • Under Voltage Lockout level of 12.5V (on) and 7.5V (min)
  • Direct optocoupler connection
  • SPICE models available for TRANsient analysis
  • Internal minimum TOFF
  • Auxiliary power supplies (USB, appliances, TVs etc.)
  • Pb-Free Packages are Available
Applications
  • AC/DC adapters for notebooks etc.
  • Offline battery chargers
  • Consumer electronics (DVD players, set-top 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
Data Sheets (1)
Document TitleDocument ID/SizeRevisionRevision Date
Controller, Free Running Quasi-Resonant Current ModeNCP1377/D (190kB)13
Application Notes (4)
Document TitleDocument ID/SizeRevisionRevision Date
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
Stability Analysis in Multiple Loop SystemsAND8327/D (213.0kB)0
Synchronizing NCP1207 (NCP1377/B, NCP1378)AND8187/D (46.0kB)0
Package Drawings (3)
Document TitleDocument ID/SizeRevision
PDIP-7 (PDIP-8 LESS PIN 7)626B (34.7kB)D
SOIC 7 CASE OUTLINE751U (62.0kB)E
SOIC-8 Narrow Body751-07 (62.6kB)AK
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
Order Information
ProductStatusCompliancePackageMSL*ContainerBudgetary Price/Unit
NCP1377BD1R2GActivePb-free Halide freeSOIC-7751U1Tape and Reel2500$0.35
NCP1377BDR2GActivePb-free Halide freeSOIC-8751-071Tape and Reel2500$0.35
NCP1377BPGActivePb-free Halide freePDIP-8626BNATube50$0.4667
NCP1377D1R2GActivePb-free Halide freeSOIC-7751U1Tape and Reel2500$0.35
NCP1377DR2GActivePb-free Halide freeSOIC-8751-071Tape and Reel2500$0.35
NCP1377PGActivePb-free Halide freePDIP-8626BNATube50$0.35
Specifications
ProductTopologyControl Modefsw Typ (kHz)Stand-by ModeUVLO (V)Short Circuit ProtectionLatchSoft StartVCC Max (V)Drive Cap. (mA)
NCP1377BD1R2GFlybackCurrent ModeVariableYesYesNoYesYes16500 / 500
NCP1377BDR2GFlybackCurrent ModeVariableYesYesNoYesYes16500 / 500
NCP1377BPGFlybackCurrent ModeVariableYesYesNoYesYes16500 / 500
NCP1377D1R2GFlybackCurrent ModeVariableYesYesNoYesYes16500 / 500
NCP1377DR2GFlybackCurrent ModeVariableYesYesNoYesYes16500 / 500
NCP1377PGFlybackCurrent ModeVariableYesYesNoYesYes16500 / 500
Controller, Free Running Quasi-Resonant Current Mode (190kB) NCP1377
Worksheet, QR Power Supply, Basic NCP1377
Worksheet, QR Power Supply, Complex NCP1377
A Quasi-Resonant SPICE Model Eases Feedback Loop Designs NCP1377
Determining the Free-Running Frequency for QR Systems NCP1377
Stability Analysis in Multiple Loop Systems NCP1055
Synchronizing NCP1207 (NCP1377/B, NCP1378) 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
SOIC 7 CASE OUTLINE NCL30060
SOIC-8 Narrow Body CM1216
PDIP-7 (PDIP-8 LESS PIN 7) NCP1129
NCP1377