NCV5171 ON Semiconductor, NCV5171 Datasheet
NCV5171
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NCV5171 Summary of contents
Page 1
... NCV5171 1.5 A 280 kHz Boost Regulators The NCV5171 is a 280 kHz switching regulator with a high efficiency, 1.5 A integrated switch. The part operates over a wide input voltage range, from 2 The flexibility of the design allows the chip to operate in most power supply configurations, including boost, flyback, forward, inverting, and SEPIC ...
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... MAXIMUM RATINGS Pin Name Pin Symbol IC Power Input Shutdown/Sync Loop Compensation Voltage Feedback Input Test Pin Power Ground PGND Analog Ground AGND Switch Input NCV5171 R2 3. PGND AGND ...
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... Maximum Duty Cycle FB Frequency Shift Threshold Sync/ Shutdown Sync Range Sync Pulse Transition Threshold SS Bias Current Shutdown Threshold Shutdown Delay 2. Guaranteed by design, not 100% tested in production. NCV5171 (2.7 V< V < -40°C < T < 125°C unless otherwise stated Test Conditions V tied to FB; measure at FB ...
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... High current switch pin. This pin connects internally to the collector of the power switch. The open voltage SW across the power switch can be as high minimize radiation, use a trace as short as practical. NCV5171 (2.7 V< V < -40°C < T < 125°C unless otherwise stated.) ...
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... V CC Shutdown 2.0 V Regulator Delay Timer Sync SS 0.4 V Detector Positive Error Amp 1.276 V AGND NCV5171 Thermal Shutdown S PWM Oscillator Q Latch R Frequency Shift 5:1 Slope Compensation PWM Compar‐ ator + - V C Figure 2. Block Diagram http://onsemi.com Switch Driver × PGND Ramp Summer ...
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... CC 1200 1000 800 600 400 200 0 500 I (mA) SW Figure 5. V vs. I CE(SAT) 285 280 275 270 265 260 255 0 Temperature (°C) Figure 7. Switching Frequency vs. Temperature NCV5171 2 100 Figure 4. DI 1.9 -40 °C 1.8 85 °C 1.7 25 °C 1 ...
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... 2.20 0 Temperature (°C) Figure 11. Current Limit vs. Temperature 1.7 V High Clamp Voltage C 1.5 1.3 1.1 V Threshold 0 Temperature (°C) Figure 13. V Threshold and High Clamp C Voltage vs. Temperature NCV5171 0. 0.18 0.16 0.14 0. 0.10 0.08 100 2 100 Figure 12. Maximum Duty Cycle vs. Temperature 1 ...
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... V (V) IN Figure 17. I vs. V During Shutdown CC IN 100 60 20 -20 -60 -255 -175 -125 - (mV) REF FB Figure 19. Error Amplifier I NCV5171 2 -10 100 600 -40°C 550 25°C 85°C 500 450 Figure 18. Error Amplifier Transconductance 2 ...
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... Without discrediting its apparent merits, current mode control comes with its own peculiar problems, mainly, subharmonic oscillation at duty cycles over 50%. NCV5171 solves this problem by adopting a slope compensation scheme in which a fixed ramp generated by the oscillator is added to the current ramp. A proper slope rate is provided to improve circuit stability without sacrificing the advantages of current mode control ...
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... Once V NCV5171 approximately 1.5 V, the internal power switch briefly turns on. This is a part of the NCV5171's normal operation. The turn-on of the power switch accounts for the initial current swing. When the V ...
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... Schottky diodes and 0.8 V for ultrafast recovery diodes V SW(MAX OUT(MAX where output diode forward voltage. F NCV5171 In the flyback topology, peak V V SW(MAX CC(MAX) )(V OUT ) where transformer turns ratio, primary over secondary. When the power switch turns off, there exists a voltage spike superimposed on top of the steady-state voltage ...
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... To maintain a stable voltage supply to the chip, a storage capacitor larger than 20 mF with low ESR is required. To reduce the noise generated by the inductor, insert a 1.0 mF ceramic capacitor between V as close as possible to the chip. NCV5171 Output Capacitor Selection V ripple CC I ...
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... Figure 30. Current Limiting using a Diode Clamp NCV5171 Another solution to the current limiting problem is to externally measure the current through the switch using a sense resistor. Such a circuit is illustrated in Figure 31 Figure 31. Current Limiting using a Current Sense The switch current is limited to ...
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... C3 Figure 32. Technique for Increasing Slope Compensation The dashed box contains the normal compensation circuitry to limit the bandwidth of the error amplifier. NCV5171 Resistors R2 and R3 form a voltage divider off of the V pin. In normal operation, V wave, and is dependent on the converter topology. Formulas for calculating V given in the section “V ...
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... Calculating Junction Temperature To ensure safe operation of NCV5171, the designer must calculate the on-chip power dissipation and determine its expected junction temperature. Internal thermal protection circuitry will turn the part off once the junction temperature exceeds 180°C ± 30°. However, repeated operation at such high temperatures will ensure a reduced operating life ...
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... JA For the NCV5171, q =165°C/W. JA Once the designer has calculated T whether the NCV5171 can be used in an application is settled exceeds 150°C, the absolute maximum J allowable junction temperature, the NCV5171 is not suitable for that application approaches 150°C, the designer should consider J possible means of reducing the junction temperature ...
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... V (8) SW AGND (6) NCV5171 (2) C 3.3 V Input, 5.0 V/ 400 mA Output Boost Converter P6KE-15A V (5) CC 1N4148 V (8) SW NCV5171 ( ( NCV5171 (8) SW AGND (6) FB (2) PGND (7) http://onsemi.com 17 5 3.6 k GND 1.3 k MBRS140T3 - GND 1:2 +12 V MBRS140T3 10.72 k GND 1 ...
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... FB 3 Test +5.0 V GND Figure 39. Additional Application Diagram, 5.0 V Input, ± Output Dual Boost Converter NCV5171 (5) CC PGND ( AGND ( NCV5171 (2) 12. 1N4148 1N4148 1N4148 ...
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... C 1.35 1.75 0.053 0.069 D 0.33 0.51 0.013 0.020 G 1.27 BSC 0.050 BSC H 0.10 0.25 0.004 0.010 J 0.19 0.25 0.007 0.010 J K 0.40 1.27 0.016 0.050 0.25 0.50 0.010 0.020 S 5.80 6.20 0.228 0.244 mm inches ON Semiconductor Website: www.onsemi.com Order Literature: http://www.onsemi.com/orderlit For additional information, please contact your local Sales Representative NCV5171/D _ ...