NCP1351 ON Semiconductor, NCP1351 Datasheet
NCP1351
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NCP1351 Summary of contents
Page 1
... An externally adjustable timer permanently monitors the feedback activity and protects the supply in presence of a short-circuit or an overload. Once the timer elapses, NCP1351 stops switching and stays latched for version A, and tries to restart for version B. Versions C and D include a dual overcurrent protection trip point, allowing the implementation of the controller in peak-power requirements applications such as printers and so on ...
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... Oscillator Frequency 3 CS Current Sense Input 4 GND 5 DRV Driver Output 6 V Supply Input CC 7 Latch Latchoff Input 8 Timer Fault Timer Capacitor OVERCURRENT PROTECTION ON NCP1351 VERSIONS: NCP1351 NCP1351 NCP1351 LATCH Figure 1. Typical Application Circuit Injecting Current in this Pin Reduces Frequency A capacitor sets the maximum switching frequency at no feedback current – ...
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... 45k OFFset ICS-dif* ICS-dif* CS ICS-min GND + Vth *(ICS-diff = ICS-max -ICS-min) Figure 2. A Version (Latched Short-Circuit Protection) NCP1351 INTERNAL CIRCUIT ARCHITECTURE + - I P Flag + V Fault Reset Pulse http://onsemi.com Filter + - V DD ...
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... 45k OFFset ICS-dif* ICS-dif* CS ICS-min GND + *(ICS-diff = ICS-max -ICS-min) Vth Figure 3. B Version (Auto-recovery Short-Circuit Protection) NCP1351 Flag + V Fault Reset Pulse http://onsemi.com TIMER TIMER ...
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... 45k OFFset ICS-dif* ICS-dif* CS ICS-min GND + *(ICS-diff = ICS-max -ICS-min) Vth Figure 4. C Version (Latched Short-Circuit Protection) NCP1351 + Fault CLK Reset Pulse http://onsemi.com Filter + - TIMER TIMER ...
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... 45k OFFset ICS-dif* ICS-dif* CS ICS-min GND + *(ICS-diff = ICS-max -ICS-min) Vth Figure 5. D Version (Auto-recovery Short-Circuit Protection) NCP1351 Fault CLK Reset Pulse http://onsemi.com TIMER TIMER ...
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... Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability. NOTE: This device contains latchup protection and exceeds 100 mA per JEDEC Standard JESD78. NCP1351 Rating ), Pin 5 (DRV and Pin 5 (DRV) ...
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... DRVhigh CC Protection I Timing Capacitor Charging Current TIMER V Fault Voltage on Pin 8 TIMER T Fault Timer Duration, C TIMER TIMER V Latching Voltage LATCH 1. Guaranteed by design. NCP1351 = 25°C, for Min/Max Values Rating = 50 mA kHz and mA kHz and mA 0° ...
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... If the event lasts longer than what the fault timer authorizes, then the NCP1351 either latches-off (C Version) or enters an auto-recovery mode (D Version). The level at which the timer starts is internally set to 55% of the maximum power capability ...
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... Setpoint I Lp Figure 6. Positive Current-Sense Technique NCP1351 APPLICATION INFORMATION current increases. When the result reaches the threshold voltage (around 20 mV), the comparator toggles and resets the main latch. Figure 3 details how the voltage moves on the CS pin on a 1351 demoboard, whereas Figure 9 zooms on the sense resistor voltage captured by respect to the controller ground ...
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... We have chosen the second scheme NCP1351 Figure 9. The Voltage Across the Sense in this NCP1351 for simplicity and ease of implementation. Thus, once the peak current has been selected, the feedback loop automatically reacts to satisfy Equations 5 and 6. The external capacitor that you connect between pin 2 and ...
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... The maximum threshold level in standby conditions is set Over Power Protection As any universal-mains operated converters, the output power slightly increases at high line compared to what the NCP1351 = Figure 12. C power supply can deliver at low line. This discrepancy relates to the propagation delay from the point where the peak is detected to the MOSFET gate effective pulldown ...
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... R OPP + (eq. 9) After experimental measurements, the resistor was , purposely limits 3 normalized down to 100 kW. Feedback Unlike other controllers, the feedback in the NCP1351 works in current rather than voltage. Figure 15 details the 56 + -4.2 V internal circuitry of this particular section. The optocoupler (eq. 270 p injects a current into the FB pin in relationship with the 10) input/output conditions ...
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... R offset 3. sense Figure 15. The Feedback Section Inside the NCP1351 The FB pin can actually be seen as a diode, forward biased by the optocoupler current. The feedback current, I Figure 15, enter an internal 45 kW resistor which develops a voltage. This voltage becomes the variable threshold point for the capacitor charge, as indicated by Figure 10. Thus, in ...
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... Figure 16. The NCP1351 Peak Current Compression Scheme Looking to the data-sheet specifications, the maximum peak current is set to 270 mA whereas the compressed current goes down to 70 mA. The NCP1351 can thus be considered as a multi operating mode circuit: • Real fixed peak current / variable frequency mode for FB current below 60 mA. • ...
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... If the fault disappears, the timer capacitor is simply reset internal switch. On version C and D, the error flag is asserted as soon as the current feedback imposes a switching frequency roughly equal to half of the maximum limit. For instance, should the NCP1351 + - + V timer ...
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... FB reacts FB reacts V V timer timer startup startup DRV DRV Figure 21. The B Version Enters an Auto-Recovery Burst Mode in Presence of a Fault NCP1351 The figures below details circuits operation for the various controller options. Pulldown Pulldown SCR action SCR action Latched Latched state state ...
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... timer timer startup startup DRV DRV Figure 23. The D Version Enters Auto-Recovery Burst Mode if the Power Excursion Exceeds 50% of the Maximum Power (DCM Full Load Operation) NCP1351 Pulldown Pulldown User User SCR action SCR action reset reset Latched Latched state ...
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... The best is to directly sense the output voltage and reacts if it runs away, as offered on the right Design Example Universal Mains Power Supply Designing a Switch-Mode Power Supply using the NCP1351 does not differ from a fixed frequency design. What changes, however, is the regulation method via frequency variations. ...
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... Large K: approaching BCM where the RMS losses are the worse, but smaller inductance, leading to a better leakage inductance. NCP1351 From Equation 17 factor of 0.8 (40% ripple) ensures a good operation over universal mains. It leads to an inductance of: ( 100 L + ...
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... P @ no-load = 152 mW 230 Vac no-load = 164 mW 100 Vac in in The efficiency stays flat to above 80%, and keeps good even at low output levels. It clearly shows the benefit of the variable frequency implemented in the NCP1351. NCP1351 R3 R4 47k 500mH ...
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... V out 50 mV/div Figure 31. Transient Step, Low Line NCP1351 Finally, the power supply was tested for its transient response, from 100 high and low line, with a slew-rate of 1 A/ms (Figure 31). Results appear in Figures 31 and 32 and confirm the stability of the board. ...
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... TEMPERATURE (°C) Figure 35. I versus Junction CSmin Temperature 517 515 513 511 509 - TEMPERATURE (°C) Figure 37. Oscillator Offset Voltage versus Junction Temperature NCP1351 CHARACTERIZATION CURVES 9.1 9 8.9 8.8 8.7 75 100 125 -25 Figure 34. V 274 270 266 262 258 254 75 100 125 ...
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... TEMPERATURE (°C) Figure 41. K Variations versus Junction FAULT Temperature 5.2 5.1 5 4.9 4.8 4.7 -25 Figure 43. Latch Level Evolution versus Junction Temperature NCP1351 990 980 970 960 950 940 930 75 100 125 -25 Figure 40. Fault Voltage Variations versus Junction Temperature (C and D Versions) 53 52.5 52 51.5 51 50.5 50 49.5 75 100 ...
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... ORDERING INFORMATION Device NCP1351ADR2G NCP1351BDR2G NCP1351CDR2G NCP1351DDR2G NCP1351APG NCP1351BPG NCP1351CPG NCP1351DPG †For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specifications Brochure, BRD8011/D. NCP1351 Package Type SOIC-8 (Pb-Free) SOIC-8 (Pb-Free) SOIC-8 ...
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... G C SEATING PLANE - 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. NCP1351 PACKAGE DIMENSIONS SOIC-8 D SUFFIX CASE 751-07 ISSUE 0.10 (0.004 SOLDERING FOOTPRINT* 1 ...
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... C 3.94 4.45 0.155 0.175 D 0.38 0.51 0.015 0.020 F 1.02 1.78 0.040 0.070 G 2.54 BSC 0.100 BSC H 0.76 1.27 0.030 0.050 J 0.20 0.30 0.008 0.012 K 2.92 3.43 0.115 0.135 L 7.62 BSC 0.300 BSC --- 10 --- 10 N 0.76 1.01 0.030 0.040 ON Semiconductor Website: www.onsemi.com Order Literature: http://www.onsemi.com/orderlit For additional information, please contact your local Sales Representative NCP1351/D ...