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发表于 2008-11-13 11:43:34
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> 弱弱的跟风问一下,
> 开关电源的开关二字怎么理解?
可以理解成快速通断,维基百科上的解释,摘录了一段,如下:
A switched-mode power supply (also switching-mode power supply and SMPS) is an electronic power supply unit (PSU) that incorporates a switching regulator. While a linear regulator maintains the desired output voltage by dissipating excess power in a pass power transistor, the SMPS rapidly switches a power transistor between saturation (full on) and cutoff (completely off) with a variable duty cycle whose average is the desired output voltage. The resulting rectangular waveform is low-pass filtered with an inductor and capacitor. The main advantage of this method is greater efficiency because the switching transistor dissipates little power in the saturated state and the off state compared to the semiconducting state (active region). Other advantages include smaller size and lighter weight (from the elimination of low frequency transformers which have a high weight) and lower heat generation due to higher efficiency. Disadvantages include greater complexity, the generation of high amplitude, high frequency energy that the low-pass filter must block to avoid electromagnetic interference (EMI), and a ripple voltage at the switching frequency and the harmonic frequencies thereof.
SMPS can be classified into four types according to the input and output waveforms:
AC in, DC out: rectifier, off-line converter input stage
DC in, DC out: voltage converter, or current converter, or DC to DC converter
AC in, AC out: frequency changer, cycloconverter
DC in, AC out: inverter |
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