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WEBENCH® Power Designer
MOSFET selector and other new features of this online tool help reduce solution design time and cost
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View National's portfolio of SIMPLE SWITCHER products
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Energy-efficient products with excellent performance-to-power ratios
Application Notes
AN-1930: SIMPLE SWITCHER Regulators For Automotive Applications
AN-1888: LM22670 Evaluation Board For Inverting Topology
Article
Buck-boost Topology Delivers Negative Output from Positive Input
Power Management DesignLine
Electronic circuit designs often require power sources with negative output voltages. An easy method of obtaining the negative voltage is the polarity-inverting (buck-boost) converter topology. The biggest advantages of this topology are the low external component count with relatively low cost, the high- power conversion efficiency mostly due to the few power stage components involved, and the vast selection of buck regulator and controller ICs that can be used for the inverting topology.
To make design easier, National Semiconductor offers an evaluation board that implements the polarity-inverting topology using the LM22670 3A SIMPLE SWITCHER® step-down voltage regulator. National’s SIMPLE SWITCHER regulators provide the performance, flexibility, and tools needed to design, prototype, and finalize designs quickly and easily.
The LM22680, recently added to the LM2267x/LM22680 series, has wide-input voltage range from 4.5V to 42V as well as pin-to-pin compatibility to 0.5A, 1.0A, and 3.0A devices within the LM2267x series. Additional features include an adjustable frequency and frequency synchronization up to 1MHz, adjustable soft-start, and a precision enable.
3A SIMPLE SWITCHER Step-Down (Buck) Voltage Regulator
The LM22670 series of regulators includes monolithic integrated circuits that provide all of the active functions for a step-down (buck) switching regulator capable of driving up to 3A loads with excellent line and load regulation characteristics. High efficiency (>90%) is obtained through the use of a low ON-resistance N-channel MOSFET. The series consists of a fixed 5V output and an adjustable version.
SIMPLE SWITCHER Family of Products
SIMPLE SWITCHER products feature an easy to use, complete set of design resources that utilize a minimum number of external components combined with National’s WEBENCH® Power Designer online design tool. The WEBENCH Power Designer tool includes external component calculation, electrical simulation, thermal simulation, and Build-It boards for easy design-in.
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