NCP1927DR2G ON Semiconductor, NCP1927DR2G Datasheet
NCP1927DR2G
Specifications of NCP1927DR2G
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NCP1927DR2G Summary of contents
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... Y = Year WW = Work Week G = Pb−Free Package ORDERING INFORMATION Device Package NCP1927DR2G SOIC−16 (Pb−Free) †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. Flyback Controller Features • 65 kHz Fixed−Frequency Operation with Built−In Ramp Compensation • ...
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Figure 1. Typical Application Example http://onsemi.com 2 ...
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Flyback_OVLD GOS Timer GTS R GTS GTS Timer V standby 30 ms Filter V UVP 30 ms POVUV Filter OVP_int I UVP V OVP V disable PControl(boost) PFC_OK 0.955*V REF PFB V REF 0 mA Detect PControl ...
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PIN FUNCTION DESCRIPTION Pin No. Pin Name 1 POVUV The gate drive is disabled while V 2 PFB This pin receives a portion of the pre−converter output voltage. This information is used for the regulation and the “output low” detection ...
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MAXIMUM RATINGS (Note 1) Rating Supply Pin (pin 13) (Note 2) Voltage Range Current Range PFC Drive Pin (pin 14) (Note 2) Voltage Range Current Range Flyback Drive Pin (pin 12) (Note 2) Voltage Range Current Range Inverter Enable Pin ...
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ELECTRICAL CHARACTERISTICS 2 PSKIP FFB FCS values T = 25°C, for min/max values − 25°C to 125°C, unless otherwise noted Characteristics SUPPLY ...
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ELECTRICAL CHARACTERISTICS 2 PSKIP FFB FCS values T = 25°C, for min/max values − 25°C to 125°C, unless otherwise noted Characteristics FLYBACK ...
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ELECTRICAL CHARACTERISTICS 2 PSKIP FFB FCS values T = 25°C, for min/max values − 25°C to 125°C, unless otherwise noted Characteristics PFC ...
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ELECTRICAL CHARACTERISTICS 2 PSKIP FFB FCS values T = 25°C, for min/max values Characteristics PFC FAULT PROTECTION Overvoltage Protection Threshold Overvoltage Protection Hysteresis ...
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INTRODUCTION The NCP1927 is a combination power factor correction (PFC) and flyback controller optimized for use in Flat Panel TVs. This device includes all the features needed to implement a highly efficient and compact power supply. It integrates a critical ...
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start NCP1927 Figure 3. Operation with Dual CC(on) V CC(off) V CC(reset DRV PDRV PDRV FDRV FDRV ...
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Figure 6. V Behavior During Shutdown Mode CC THERMAL SHUTDOWN When the junction temperature exceeds T minimum), a temperature sensing circuit disables the gate drives and a V hiccup occurs (see Figure 5). When V CC reaches V , the ...
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Short−Winding Protection Under some conditions, like a transformer winding or output diode short−circuit, the primary current increases above V before the LEB timer expires. To prevent ILIM dangerously high current from flowing, an additional comparator senses when V reaches V ...
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When calculating the proper value for R necessary to express the internal ramp signal in terms of its slope (dI /dt). This is done using Equation 3. OSC ramp(MAX) OSC + dt D MAX The inductor ...
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Soft−Skip timer instead of the feedback voltage. Since the LEB of the FCS Pin prevents operation at nearly 0% duty ratio, the controller instead compares the soft−skip ramp to an internal ...
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PFC CONTROLLER The PFC stage operates in critical conduction mode (CrM). CrM occurs at the boundary between discontinuous conduction mode (DCM) and continuous conduction mode (CCM). In CrM, the driver on time is initiated when the boost inductor current reaches ...
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Output Regulation The NCP1927 error amplifier (EA) consists of an operational transconductance amplifier (OTA) with the inverting input connected to the PFB pin and the output connected to the PControl pin to regulate the output voltage. It features a typical ...
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Transient Load Detection Due to the low bandwidth of the regulation loop, fast load transients may result in output voltage over and undershoots. Overshoots are limited by the overvoltage protection (see OVP section). To control the undershoots, an internal comparator ...
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V PDRV V drain V out V PZCD V CL(POS) V ZCD(rising) V ZCD(falling) V CL(NEG) ZCD Winding V ZCD(off) V ZCD(on) Figure 23. Voltage Waveforms for Zero Current Detection During startup, there are no ZCD transitions to enable the ...
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V out V out(nom) PDRV OVP Figure 25. OVP Timing Diagram V out R POVUV1 POVUV R POVUV2 Figure 26. POVUV Pin Block The NCP1927 detects a UVP fault when the output voltage falls below the UVP limit. During a ...
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Skip Mode Operation The NCP1927 automatically skips switching cycles when the power demand drops below a given level. This is accomplished by monitoring the internal offset PControl voltage. This voltage is compared to the PCT ramp to control the power ...
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Go To Standby Pin The Go To Standby (GTS) pin is used to disable the PFC stage during system standby based on the flyback stage load condition. This can be done by connecting it to the flyback stage feedback pin ...
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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. Soft−Skip is a trademark of Semiconductor Components Industries, LLC (SCILLC). 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 ...
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