LM3450MT/NOPB National Semiconductor, LM3450MT/NOPB Datasheet
LM3450MT/NOPB
Specifications of LM3450MT/NOPB
Related parts for LM3450MT/NOPB
LM3450MT/NOPB Summary of contents
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... A dy- namic hold circuit ensures that the phase dimmer angle is decoded properly while minimizing the extra power losses associated with holding current. Typical Application © 2010 National Semiconductor Corporation LM3450 Features ■ Critical conduction mode PFC ■ ...
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Connection Diagram Ordering Information Order Number Spec. Package Type LM3450 NOPB LM3450MTX NOPB www.national.com Top View 30127402 16-Lead TSSOP NS Package Number MTC16 NSC Package Drawing TSSOP-16 MTC16 92 Units, Rail TSSOP-16 MTC16 2500 Units, Tape and Reel 2 Supplied ...
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Pin Descriptions Pin Name Description Reference REF 2 V Analog Adjust ADJ 3 FLT2 Filter 2 4 FLT1 Filter 1 500 Hz 5 DIM PWM Output Sampled Rectified Line 7 COMP Compensation 8 FB ...
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... Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications HOLD, DIM, BIAS CC HOLD Power BIAS Current ZCD Current COMP, FB FLT1, FLT2 CS, V REF ADJ I SEN GATE -0.3V to 18V Continuous -1mA to +1mA Continuous ...
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Symbol Parameter K Multiplier Gain (Includes Internal M Resistor Divider) ZERO CURRENT DETECTOR (ZCD) V ZCD Input Threshold ZCD-RIS Hysteresis Delay to Output V Positive Clamp Voltage ZCD-H V Negative Clamp Voltage ZCD-L PWM COMPARATOR (CS) V PWM Comparator Input ...
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Symbol Parameter THERMAL SHUTDOWN Thermal Limit Threshold Thermal Limit Hysteresis THERMAL RESISTANCE θ Junction to Ambient JA θ Junction to Case JC Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the component may occur. Operating Ratings are ...
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Typical Performance Characteristics HOLD R vs. Junction Temperature DSON Current Limit Threshold vs. Junction Temperature CMP THM Transconductance = 2.5V; Δ 50mV =+25°C and V A Leading Edge ...
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V UVLO Threshold vs. Junction Temperature CC V Reference vs. Junction Temperature REF I Reference vs. Junction Temperature SEN www.national.com Shutdown Current vs. Junction Temperature 30127409 FB Reference vs. Junction Temperature 30127411 V Detection Threshold vs. Junction Temperature AC 30127413 ...
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Transconductance vs 30127416 Current Sense Threshold vs and V COMP AC 30127417 www.national.com ...
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Block Diagram www.national.com 10 30127421 ...
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Theory of Operation The LM3450 is a single device with both power factor control (PFC) and phase dimming decoder functions. This device is designed to control isolated flyback converters and provide active power factor correction. In addition to being a ...
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PFC BACKGROUND Power factor (PF number between 0 and 1 that indicates how well energy is transmitted from input to output of a sys- tem. It can be described by average power (P voltage (V ), and RMS ...
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FIGURE 3. Basic CRM Inductor Current Waveform CRM BACKGROUND During critical conduction mode (CRM), a converter operates at the boundary of continuous conduction mode (CCM) and discontinuous conduction mode (DCM). This is usually im- plemented as follows. The main switching ...
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POWER FACTOR CONTROLLER The LM3450 uses CRM control to regulate the output voltage and provide power factor correction non-isolated boost topology, an external voltage divider (R sense the output voltage, as shown in is connected to the inverting ...
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FIGURE 6. ZCD Waveforms for Flyback Design ZERO CURRENT DETECTION ZCD is implemented with a 100kΩ resistor from the ZCD pin to a coupled winding on the transformer or inductor as shown in Figure 5. This winding is also used ...
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PHASE DIMMER OPERATION A simplified schematic of a phase dimmer is shown network consisting of R1, R2, and C1 delay the turn the triac until the voltage on C1 reaches the trigger voltage of ...
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PHASE DIMMING DECODER The LM3450 uses the rectified AC line voltage to interpret the conduction angle. Figure 10 shows the LM3450 decoder cir- cuit with associated external circuitry. The rectified AC line voltage is scaled via a resistor divider (R ...
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This PWM signal at the DIM pin can be used as the dim input to a secondary LED driver. DIM is an open drain output de- signed for isolated solutions. Optical isolation is used to trans- mit signals across the ...
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DYNAMIC HOLD A forward phase “triac” dimmer requires a minimum amount of current to be flowing through it during the entire conduction angle. This is referred to as hold current. If the minimum hold current requirement is not met, the ...
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FIGURE 17. Reverse Phase Waveforms The dynamic hold will quickly bleed off the excess charge in an attempt to regulate the voltage across RSEN. This will preserve the accuracy of the decoded phase angle. During the conduction angle (θ), dynamic ...
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PRIMARY BIAS SUPPLY The LM3450 requires a supply voltage at V 25V. The device has V under-voltage lockout (UVLO) with CC rising and falling thresholds of 12.9V and 7.9V respectively. A 24V Zener diode should be placed from the V ...
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Applications Information See AN-2098 for detailed design and application information. TWO STAGE LED DRIVER – LM3450 Primary and LM3409 Secondary www.national.com 22 30127440 ...
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TWO STAGE DESIGN SPECIFICATIONS AC Input Voltage: 120V nominal (90V AC Regulated Flyback Output Voltage: 50V Regulated LED Current: 350mA LED Stack Voltage Maximum: 45V Bill of Materials Reference Designator Part Value LM3450 IC PFC CONT 16-TSSOP LM3409 IC ...
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R4 RES 100Ω 1%1W 2512 R5, R7, R10 RES 100kΩ 1% 0.1W 0603 R6 RES 3.01kΩ 1% 0.1W 0603 R8, R9 RES 75.0kΩ 1% 0.1W 0603 R11 RES 1.00MΩ 1% 0.25W 1206 R12 RES 14.0kΩ 1% 0.1W 0603 R13 RES ...
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25 www.national.com ...
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Physical Dimensions www.national.com inches (millimeters) unless otherwise noted TSSOP-16 Pin Package (MTC) For Ordering, Refer to Ordering Information Table NS Package Number MTC16 26 ...
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Notes 27 www.national.com ...
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