ncp1234ad100r2g ON Semiconductor, ncp1234ad100r2g Datasheet
ncp1234ad100r2g
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ncp1234ad100r2g Summary of contents
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NCP1234 Fixed Frequency Current Mode Controller for Flyback Converters The NCP1234 is a new fixed−frequency current−mode controller featuring Dynamic Self−Supply (DSS). This device is pin−to−pin compatible with the previous NCP12xx families. The DSS function greatly simplifies the design of the ...
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VIN (dc) LATCH FB CS GND Figure 1. Flyback Converter Application Using the NCP1234 PIN FUNCTION DESCRIPTION Pin No Pin Name Function 1 LATCH Latch−Off Input 2 FB Feedback 3 CS Current Sense 4 GND 5 DRV Drive output 6 ...
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SIMPLIFIED INTERNAL BLOCK SCHEMATIC − NTC V OVP I NTC − Latch + + OTP V clamp V FB(ref sample + − I ...
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MAXIMUM RATINGS Supply Pin (pin 6) (Note 2) Voltage range Current range High Voltage Pin (pin 8) (Note 2) Voltage range Current range Driver Pin (pin 5) (Note 2) Voltage range Current range All other pins (Note 2) Voltage range ...
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ELECTRICAL CHARACTERISTICS (For typical values unless otherwise noted) CC Characteristics HIGH VOLTAGE CURRENT SOURCE Minimum voltage for current source operation Current flowing out of V pin Off−state leakage current V ...
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ELECTRICAL CHARACTERISTICS (For typical values unless otherwise noted) CC Characteristics FEEDBACK Internal pull−up resistor T = 25° internal current setpoint FB division ratio Internal pull−up voltage on the FB pin CURRENT SENSE ...
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ELECTRICAL CHARACTERISTICS (For typical values unless otherwise noted) CC Characteristics LATCH−OFF INPUT High threshold V Latch Low threshold V Latch Current source for direct NTC V Latch connection During normal operation During soft−start Blanking duration ...
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TYPICAL PERFORMANCE CHARACTERISTICS 40.00 38.00 36.00 34.00 32.00 30.00 28.00 26.00 24.00 22.00 20.00 −50 − TEMPERATURE (°C) Figure 3. Minimum Current Source Operation V HV(min) 0.75 0.74 0.73 0.72 0.71 0.70 0.69 0.68 0.67 0.66 0.65 ...
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TYPICAL PERFORMANCE CHARACTERISTICS −50 − TEMPERATURE (°C) Figure 9. FB Pin Internal Pull−up Resistor R FB(up ...
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TYPICAL PERFORMANCE CHARACTERISTICS 0.77 0.75 0.73 0.71 0.69 0.67 0.65 0.63 −50 − TEMPERATURE (°C) Figure 15. FB Pin Skip−in Level −50 − ...
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TYPICAL PERFORMANCE CHARACTERISTICS 2.65 2.60 2.55 2.50 2.45 2.40 2.35 −50 − TEMPERATURE (°C) Figure 21. Latch Pin High Threshold V 1.34 1.32 1.30 1.28 1.26 1.24 1.22 1.20 1.18 −50 − TEMPERATURE (°C) ...
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Introduction The NCP1234 includes all necessary features to build a safe and efficient power supply based on a fixed−frequency flyback converter particularly well suited for applications where low part count is a key parameter, without sacrificing safety. • ...
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Light load operation: When the FB voltage decreases below V , typically corresponding to a load of FB(foldS) 33% of the maximum load (for a DCM design), the switching frequency starts to decrease down lowering ...
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High−Voltage Current Source with Built−in Brown−out Detection The NCP1234 HV pin can be connected either to the rectified bulk voltage the ac line through a rectifier. Start−up HV VCC Figure 27. HV Start−up Current Source Functional Schematic At ...
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HV(min CC(on) V CC(min) V CC(inhibit) DRV For safety reasons, the start−up current is lowered when V is below reduce the power dissipation in CC CC(inhibit) case the V pin is ...
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The board is unplugged HV(min CC(on) V CC(min) V CC(off) Controller stops at V CC(off) Output Loss of regulation when V is too low HV DRV Fault timer (internal) Figure 29. Fast Application Off ...
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Oscillator with Maximum Duty Cycle and Frequency Jittering The NCP1234 includes an oscillator that sets the switching frequency with an accuracy of $7%. Two frequency options can be ordered: 65 kHz and 100 kHz. The maximum duty cycle of the ...
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CURRENT−MODE CONTROL WITH OVERPOWER COMPENSATION AND SOFT−START Current sensing NCP1234 is a current−mode controller, which means that the FB voltage sets the peak current flowing in the inductance and the MOSFET. This is done through a PWM comparator: the current ...
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FB(fault) Soft-start ramp V ILIM CS Setpoint V ILIMI Under some conditions, like a winding short−circuit for instance, not all the energy stored during the on time is transferred to the output during the off time, even ...
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LIMIT High Line Figure 34. Line Compensation for True Overpower Protection To compensate this and have an accurate overpower protection, an offset proportional to the input voltage is added on the CS signal by turning on an ...
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I OPC V FB(OPCE) Figure 36. Overpower Compensation Current Relation to Feedback Voltage and Input Voltage HVsample Peak detector Reset I Sample OPC Sample Figure 37. Overpower Compensation Current if the HV Pin is Connected to AC ...
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HV(stop Peak detector I OPC Sample Figure 38. Overpower Compensation if the HV Pin is Connected to DC Voltage Feedback with Slope Compensation The ratio from the FB voltage to the current sense setpoint is ...
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Overcurrent protection with Fault timer When an overcurrent occurs on the output of the power supply, the FB loop asks for more power than the controller can deliver, and the CS setpoint reaches V event occurs, an internal t timer ...
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In autorecovery mode, the controller tries to restart after t the system starts a new burst cycle. Overcurrent Output Load applied Max Load Fault Flag starts CC(on) V CC(min) DRV Fault timer t fault t fault Figure ...
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In the latched version, the controller can restart only if a brown−out reset occurs, which in a real application CC Output Load Overcurrent applied Max Load Fault Flag Fault timer starts CC(on) V CC(min) ...
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Frequency Foldback In order to improve the efficiency in light load conditions, the frequency of the internal oscillator is linearly reduced from its nominal value down to f OSC(min) foldback starts when the voltage on FB pin goes below f ...
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FB(fold) V skip(out) V skip(in) Enters skip DRV Latch−off Input VDD I NTC Latch clamp Soft−start The Latch pin is dedicated to the latch−off function: it includes two levels of detection that define a ...
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DRV switching starts only allowed; whereas the Low latch (typically sensing an overtemperature) is taken into account only after the soft−start is finished. In addition, the NTC current is doubled to I the soft−start period, ...
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HV Start−up Current Source No TSD TSD Stop Figure 48. HV Start−up Current Source State Diagram STATE DIAGRAMS start1 V < CC(inhibit) TSD TSD V < CC(min) TSD http://onsemi.com 29 > V CC(inhibit) ...
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Controller Operation (Latched Version: A Option) • TSD Stopped • VCC reset Latch • High Latch • Low Latch • V > CC(ovp) Figure 49. Controller Operation State Diagram (Latched Protection) V > CC(on) • V ...
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Controller Operation (Autorecovery Version: B Option) • t counting autorec • TSD Stopped • VCC reset Latch • High Latch • Low Latch • V > CC(ovp) Figure 50. Controller Operation State Diagram (Autorecovery Protection) V > V ...
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... Table 1. ORDERING INFORMATION Part No. Overload Protection NCP1234AD65R2G NCP1234BD65R2G NCP1234AD100R2G NCP1234BD100R2G †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. Switching Frequency Latched 65 kHz Autorecovery 65 kHz Latched 100 kHz ...
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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. “ ...