NCP1252BDR2G ON Semiconductor, NCP1252BDR2G Datasheet

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NCP1252 Current Mode PWM Controller for Forward and Flyback Applications The NCP1252 controller offers everything needed to build cost− effective and reliable ac−dc switching supplies dedicated to ATX power supplies. Thanks to the use of an internally fixed timer, NCP1252 ...

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Vbulk Table 1. PIN FUNCTIONS Pin No. Pin Name Brown−out input 3 CS Current sense 4 R Timing element T 5 GND 6 Drv SSTART Table 2. MAXIMUM RATINGS TABLE Symbol V ...

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Figure 2. Internal Circuit Architecture http://onsemi.com 3 ...

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Table 3. ELECTRICAL CHARATERISTICS ( kW nF. For typical values DRV Characteristics SUPPLY SECTION AND V MANAGEMENT CC Startup threshold at which driving pulses are au- thorized Minimum ...

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Table 3. ELECTRICAL CHARATERISTICS ( kW nF. For typical values DRV Characteristics DRIVE OUTPUT Clamping voltage (maximum gate voltage) High−state voltage drop CYCLE SKIP Skip cycle level Skip ...

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TEMPERATURE (°C) Figure 5. Start−up Current (I CC1 Temperature SUPPLY VOLTAGE Vcc (V) Figure 7. Supply Current (I CC3 Voltage ...

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TEMPERATURE (°C) Figure 11. Propagation Delay from CS to DRV vs. Junction Temperature 108 106 104 102 100 −40 −20 0 ...

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TEMPERATURE (°C) Figure 17. Maximum Duty−cycle, B Version vs. Junction Temperature ROH 8 6 ROL −40 − ...

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TEMPERATURE (°C) Figure 23. Soft Start Current vs. Junction Temperature 1.10 1.08 1.06 1.04 1.02 1.00 0.98 0.96 0.94 0.92 0.90 −40 − TEMPERATURE (°C) Figure ...

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Introduction The NCP1252 hosts a high−performance current−mode controller specifically developed to drive power supplies designed for the ATX and the adapter market: • Current Mode operation: implementing peak current−mode control topology, the circuit offers UC384X−like features to build rugged power ...

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FB level V = 6.0 V FBOL 0.3 V skip Figure 29. Mode of Operation versus the FB Pin Level Startup Sequence: The startup sequence is activated when Vcc pin reaches V level. ...

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V pin CC V CC(on) BO pin pin SS capacitor is discharged DRV pin CASE #3 Figure 31. Controller Shuts Down with the Brown Out Pin When the BO pin is grounded, the controller is shut down ...

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The following figure illustrates a soft start sequence. Brown−Out Protection By monitoring the level on BO pin, the controller protects the forward converter against low input voltage conditions. When the BO pin level falls below the V controllers stops pulsing ...

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bulkon R + BOlo bulkoff R can be also written independently of R BOup substituting Equation 4 into Equation 3 as follow bulkon R + BOup I ...

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FB Rcomp CS Rsense Ccs In the NCP1252, the internal ramp swings with a slope of: V ramp int SW DC max In a forward application the secondary−side downslope viewed on a primary side requires a projection ...

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... So in that case the natural ramp compensation due to the magnetizing inductance of the transformer will be enough to prevent any sub−harmonics oscillation in case of duty cycle above 50%. Table 4. ORDERING INFORMATION Device NCP1252ADR2G NCP1252BDR2G NCP1252CDR2G †For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specification Brochure, BRD8011/ ...

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... *For additional information on our Pb−Free strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D. ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. “ ...