ncp1377b ON Semiconductor, ncp1377b Datasheet
ncp1377b
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ncp1377b Summary of contents
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... NCP1377, NCP1377B PWM Current−Mode Controller for Free−Running Quasi−Resonant Operation 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 ...
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... GND The IC ground 5 Drv Driving pulses 6 V Supplies the − High−voltage pin NCP1377, NCP1377B R* NCP1377 Figure 1. Typical Application Schematic The auxiliary FLYBACK signal ensures discontinuous operation and offers a fixed overvoltage detection level of 7 connecting an optocoupler to this pin, the peak current setpoint is adjusted accordingly to the output power demand ...
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... Maximum ratings are those values beyond which device damage can occur. Maximum ratings applied to the device are individual stress limit values (not normal operating conditions) and are not valid simultaneously. If these limits are exceeded, device functional operation is not implied, damage may occur and reliability may be affected. NCP1377, NCP1377B 1.5 us for B Version 4.5 us ...
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... Demag Propagation Delay Timeout After Last Demag Transition Internal Input Capacitance at Vpin 1 = 1.0 V Minimum T (Internal Blanking Delay After T OFF 1. Max value please see characterization curves. j NCP1377, NCP1377B (For typical values for min/max values T j Pin kHz ...
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... Threshold versus Temperature CCON 1.60 1.40 1.20 1.00 0.80 0.60 0.40 − TEMPERATURE ( C) Figure 5. Current Consumption (No Load) versus Temperature 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 − TEMPERATURE ( C) Figure 7. HV Current Source at V versus temperature NCP1377, NCP1377B TYPICAL CHARACTERISTICS 7.90 7.80 7.70 7.60 7.50 7.40 7.30 7.20 −25 0 100 125 Figure 4. V CCMIN 2.30 2.10 1.90 1.70 1.50 1.30 1.10 100 125 −25 0 Figure 6. Current Consumption (1.0 nF Load) 1.10 1.05 1.00 0.95 0.90 −25 ...
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... Figure 9. Drive Source Resistance versus Temperature 120 100 − TEMPERATURE ( C) Figure 11. Demagnetization Detection Threshold versus Temperature 10.0 9.5 9.0 8.5 8.0 7.5 7.0 6.5 − TEMPERATURE ( C) Figure 13. Minimum T versus Temperature OFF NCP1377, NCP1377B TYPICAL CHARACTERISTICS 20.0 18.0 16.0 14.0 12.0 10.0 8.0 6.0 4.0 2.0 0.0 75 100 125 −25 0 Figure 10. Drive Sink Resistance versus 7.8 7.6 7.4 7.2 7.0 6.8 6.6 6.4 75 100 125 −25 0 Figure 12 ...
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... V typical), the startup current source is activated and brings Vcc back to Vcc where the IC attempts to startup. on NCP1377, NCP1377B Overvoltage Protection (OVP): By sampling the plateau voltage on the demagnetization winding, the NCP1377 goes into latched fault condition whenever an overvoltage condition is detected. The controller stays fully latched in this position until the Vcc is cycled down to 4 ...
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... Now, if because of a low load mode the feedback NCP1377, NCP1377B Skipping Cycle Mode The NCP1377 automatically skips switching cycles when the output power demand drops below a given level. ...
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... V −1.0 Figure 21. Core Reset Detection is Done through a Dedicated Auxiliary Winding Monitoring An internal timer prevents any restart within 8.0 ms further to the driver going−low transition for NCP1377, and 3.0 ms for NCP1377B. This prevents the switching frequency to exceed (1.0 blank NCP1377, NCP1377B Demag Restart ...
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... Overvoltage Protection The overvoltage protection works by sampling the plateau voltage after the turn−off sequence. A 4.5 ms delay for NCP1377 and 1.5 ms for NCP1377B guarantees a clean plateau, providing that the leakage inductance ringing has been fully damped. If this would not be the case, the ...
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... Disables the IC Overload Operation In applications where the output current is purposely not controlled (e.g. wall adapters delivering raw DC level interesting to implement a true short−circuit protection. A short−circuit actually forces the output voltage NCP1377, NCP1377B Aux. Winding ON/OFF CC Figure 26. A simple transistor arrangement temperature exceeds a given setpoint ...
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... V UVLO during power on) is 12.5 – 7 have a capacitor which then needs to supply the NCP1377 with 2.8 mA during a given time until the auxiliary supply takes over. Suppose that this time was measured at around NCP1377, NCP1377B Vcc min Vcc Vcc ...
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... NCP1377, NCP1377B Figure 29. This plot gathers waveforms captured at three different operating points Upper Plot: Free run, valley switching operation, Pout = Middle Plot: Min Toff clamps the switching frequency and selects the second valley Lowest Plot: The skip slices the second valley pattern and will further expand the burst as Pout goes low ...
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... NCP1377, NCP1377B Vcc (5 V/div) Latchoff Level Figure 31. The short−circuit protection forces the IC to enter burst in presence of a secondary overload. http://onsemi.com 14 Vgate (5 V/div) ...
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... H D 0.25 (0.010 *For additional information on our Pb−Free strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D. NCP1377, NCP1377B PACKAGE DIMENSIONS SOIC−8 D SUFFIX CASE 751−07 ISSUE ...
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... Literature Distribution Center for ON Semiconductor P.O. Box 61312, Phoenix, Arizona 85082−1312 USA Phone: 480−829−7710 or 800−344−3860 Toll Free USA/Canada Fax: 480−829−7709 or 800−344−3867 Toll Free USA/Canada Email: orderlit@onsemi.com NCP1377, NCP1377B PACKAGE DIMENSIONS PDIP−7 P SUFFIX CASE 626B−01 ...