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Estimating the Significant Parameters of the Power Semiconductors Table 3. Estimating the Significant Parameters of the Power Semiconductors The magnetic elements within a switching power supply are used either for stepping-up or down a switched AC voltage, or for energy storage. In forward-mode topologies, the transformer is only used for stepping-up or down the AC voltage generated by the power switches. The output filter (the output inductor and capacitor) in forward-mode topologies...

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Efficient Safety Circuit for Electronic Ballast Easy to implement circuit to avoid thermal runaway when fluorescent lamp does not strike. Power devices do not have to be oversized - lower cost solution. Includes power factor correction. MC34262 Power Factor Controller MUR120 Ultrafast Rectifier (200 V) MJE18004D2 High Voltage Planar Bipolar Power Transistor (100 V) 1N4007 General Purpose Diode (1000 V) 1N5240B Zener Voltage Regulator Diode (10 V) 100 V MJD18002D2 MJB18004D2

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Power Ground (b) Proportionai Base Drive Circuit (Baker Ciamp) Power Ground (b) Proportionai Base Drive Circuit (Baker Ciamp) Figure 16. Driving a Bipolar Junction Transistor Power MOSFETs are the popular choices used as power switches and synchronous rectifiers. They are, on the surface, simpler to use than BJTs, but they have some hidden complexities. A simplified model for a MOSFET can be seen in Figure 17. The capacitances seen in the model are specified within the MOSFET data sheets, but...

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Snubbers and clamps are used for two very different purposes. When misapplied, the reliability of the semiconductors within the power supply is greatly jeopardized. A snubber is used to reduce the level of a voltage spike and decrease the rate of change of a voltage waveform. This then reduces the amount of overlap of the voltage and current waveforms during a transition, thus reducing the switching loss. This has its benefits in the Safe Operating Area (SOA) of the semiconductors, and it...

Fully Released Technical Data

The Fully Released Technical Data document is for a product device that is in full production (i.e., fully released). It replaces the Advance Information document and represents a part that is fully qualified. The Fully Released Technical Data document is virtually the same document as the Product Preview and the Advance Information document with the exception that it provides information that is unavailable for a product in the early phases of development, such as complete parametric...

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Schematic and Waveforms for a ZVS Quasi-Resonant Buck Converter Power Factor (PF) is defined as the ratio of real power to apparent power. In a typical AC power supply application where both the voltage and current are sinusoidal, the PF is given by the cosine of the phase angle between the input current and the input voltage and is a measure of how much of the current contributes to real power in the load. A power factor of unity indicates that 100 of the current is contributing to...

Ncp1205

Quasi-resonant Operation, 250 mA Source Sink, 8-36 V Operation High Performance Current-Mode Controllers 500 kHz Freq., Totem Pole O P, Cycle-by-Cycle Current Limiting, UV Lockout Figure 39. AC DC Power Supply for Storage, Imaging & Entertainment Figure 39. AC DC Power Supply for Storage, Imaging & Entertainment Controller + 700 V Start-up & Power Switch, < 15 W

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The Waveforms of a Capacitive Input Filter A Power Factor Correction (PFC) circuit is a switching power converter, essentially a boost converter with a very wide input range, that precisely controls its input current on an instantaneous basis to match the waveshape and phase of the input voltage. This represents a zero degrees or 100 percent power factor and mimics a purely resistive load. The amplitude of the input current waveform is varied over longer time frames to maintain a...

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1600 Feehanville Drive Mount Prospect, IL 60056 website http www.component.talk.com Telephone 847-803-6100 Laying Out the Printed Circuit Board The printed circuit board (PCB) layout is the third critical portion of every switching power supply design in addition to the basic design and the magnetics design. Improper layout can adversely affect RFI radiation, component reliability, efficiency and stability. Every PCB layout will be different, but if the designer appreciates the common factors...

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An Active Clamp Used in a One Transistor Forward or a Flyback Converter A quasi-resonant topology is designed to reduce or eliminate the frequency-dependent switching losses within the power switches and rectifiers. Switching losses account for about 40 of the total loss within a PWM power supply and are proportional to the switching frequency. Eliminating these losses allows the designer to increase the operating frequency of the switching power supply and so use smaller inductors...

Zener Clamp

Common Methods for Controlling Voltage Spikes and or RFI Figure 28. The Effects of a Snubber versus a Clamp Figure 28. The Effects of a Snubber versus a Clamp A lossless snubber is a snubber whose trapped energy is recovered by the power circuit. The lossless snubber is designed to absorb a fixed amount of energy from the transition of a switched AC voltage node. This energy is stored in a capacitor whose size dictates how much energy the snubber can absorb. A typical implementation...

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Figure 42. 80 W Power Factor Controller Reduced part count, low-cost solution. Complete semiconductor solution based around highly integrated MC33262. MC33262 Power Factor Controller MUR130 Axial Lead Ultrafast Recovery Rectifier (300 V) Coilcraft N2881-A Primary 62 turns of 22 AWG Secondary 5 turns of 22 AWG Core Coilcraft PT2510 Gap 0.072 total for a primary inductance (Lp) of 320 H Application Compact Power Factor Correction Low-cost system solution for boost mode follower. Meets IEC1000-3-2...

Mje18204d2

ON Semiconductor's H2BIP process integrates a diode and bipolar transistor for a single package solution. Application AC-DC Battery Charger - Constant Current with Voltage Limit Figure 50. AC-DC Battery Charger - Constant Current with Voltage Limit 9.5 Watt capability for charging portable equipment. Light weight. ON Semiconductor Advantages Off the shelf components SPICE model available for MC33341 Figure 50. AC-DC Battery Charger - Constant Current with Voltage Limit

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Power Supply Battery Charger Regulator Control Circuit Surface Mount Ultrafast Rectifier 600 V Surface Mount Ultrafast Rectifier 200 V Zener Voltage Regulator Diode 5.1 V Zener Voltage Regulator Diode MMSZ18T1 Literature Available from ON Semiconductor These older Application Notes may contain part numbers that are no longer available, but the applications information may still be helpful in designing an SMPS. They are available through the Literature Distribution Center for ON Semiconductor at...

Switchmode Power Supply Reference Manual

SCILLC, 2002 Previous Edition 2000 All Rights Reserved'' 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...