0308 V

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...

D

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...

L

-t + nit 0 < t < ton (eq. 2) During this period, energy is stored as magnetic flux within the core of the inductor. When the power switch is turned off, the core contains enough energy to supply the load during the following off period plus some reserve energy. When the power switch turns off, the voltage on the input side of the inductor tries to fly below ground, but is clamped when the catch diode D becomes forward biased. The stored energy then continues flowing to the output through...

Smpsrm

Reference Books Relating to Switching Power Supply Design Power Semiconductor Devices, PWS Publishing Co., Boston, 1996. 624 pages. Brown, Marty, Practical Switching Power Supply Design, Academic Press, Harcourt Brace Jovanovich, 1990. 240 pages. Brown, Marty Power Supply Cookbook, EDN Series for Design Engineers, ON Semiconductor Series in Solid State Electronics, Butterworth-Heinmann, MA, 1994. 238 pages High Frequency Switching Power Supplies Theory and Design, Second Edition, McGraw-Hill,...

Switching Loss

Stresses and Losses within Rectifiers the MOSFET should be placed in parallel with the synchronous MOSFET. The MOSFET does contain a parasitic body diode that could conduct current, but it is lossy, slow to turn off, and can lower efficiency by 1 to 2 . The lower turn-on voltage of the Schottky prevents the parasitic diode from ever conducting and exhibiting its poor reverse recovery characteristic. Using synchronous rectification, the conduction voltage can be reduced from 400 mV to...

Tdk

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...

Time

A Basic Boost-Mode Converter and Waveforms (Boost Converter Shown) Again, its operation is best understood by considering the on and off periods separately. When the power switch is turned on, the inductor is connected directly across the input voltage source. The inductor current then rises from zero and is given by iL(on) < t < 0on (eq. 4) Energy is stored within the flux in the core of the inductor. The peak current, ipk, occurs at the instant the power switch is turned off and...

Mqk

Schematic and Waveforms for a ZCS Quasi-Resonant Buck Converter Figure 31. Schematic and Waveforms for a ZCS Quasi-Resonant Buck Converter In this design, both the power switch and the catch diode operate in a zero current switching mode. Power is passed to the output during the resonant periods. So to increase the power delivered to the load, the frequency would increase, and vice versa for decreasing loads. In typical designs the frequency can change 10 1 over the ZCS supply's...

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...

Ch

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

Orega Transformer G619100 Thomson Tv Components

70 W output power from 95 to 265 Vac. Load regulation 115 Vac 0.8 V. Cross regulation 115 Vac 0.2 V. Frequency 20 kHz fully stable. DIP16 or SO16 packaging options for controller. Meets IEC emi radiation standards. A narrow supply voltage design 80 W is also available. MC44603AP Enhanced Mixed Frequency Mode

Bzx84c5v1lt1

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...