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Why consider a power BJT rather than a MOSFET?

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PetJh
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re: Why consider a power BJT rather than a MOSFET?
PetJh   7/16/2011 9:57:52 AM
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Comparing just noise as on the picture is .. not correct. One of the transformers (on the left) is completely compensated - no switching waveform is available. The picture on the right (even maybe the same transformer) shows completely uncompensated mode, maybe MOSFET capacitance. It should be stated where on the 50 Hz the noise has been measured as it is completely different during conduction/nonconduction of the bridge. Both switches must be the same case, pinout etc. as ANY small change in the collector/drain are will make big effect over the CM noise.

Simon7382
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re: Why consider a power BJT rather than a MOSFET?
Simon7382   11/1/2010 5:38:43 AM
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Secondary break down can be dealt with with properly designed base drive. MOSFETs took over mostly because they were much faster, enabling higher switching frequencies and appropriately smaller DC-DC converters. However, in small off-line DC-DC converters the switching frequency is typically low (around 50-100 kHz) due to the conducted EMI limits, hence the speed advantage of MOSFETs is not an advantage but a disadvantage.

Neetin
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re: Why consider a power BJT rather than a MOSFET?
Neetin   10/28/2010 8:07:17 AM
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One of the main reasons for BJT to MOSFET shift was the elusive Secondary breakdown at high voltages. Are the new BJTs free from this problem?

Les_Slater
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re: Why consider a power BJT rather than a MOSFET?
Les_Slater   10/26/2010 8:53:44 PM
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I like seeing a fresh look at trying to meet the latest in power requirements. Why not use the relatively slow switching characteristics of the BJT to thermally dissipate an appreciable amount of the pesky noise? The most impressive though is the clever controller IC technology to keep efficiencies at competitive, and even superior, levels while at the same time reducing complexity and cost.

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