Why we use MOSFET and variable resistor in a buck boost converter ?
What are the benefits by using these components ?
What are the benefits by using these components ?
Several manufacturers publish application notes and books on such topics - obviously each manufacturer wants to steer you in the general direction of their products, but you can still get a general overview of the topology.I got you..MITECH electronics..thnx
Thank you very much buddy..MOSFETs are used because they generally make more efficient switches than bipolar transistors.
Variable resistors are used whenever you want to vary a voltage, such as the output voltage of the regulator.
You have to qualify that statement somewhat - early MOSFETs had high RDSon and wasted more power when switched on hard, than did transistors.MOSFETs are used because they generally make more efficient switches than bipolar transistors.
Variable resistors are used whenever you want to vary a voltage, such as the output voltage of the regulator.
Not sure how early obsolete high resistance MOSFETs are pertinent to this discussion. Modern MOSFETs can be readily found with a few milliohms of ON resistance, giving much less ON voltage drop as compared to BJTs.You have to qualify that statement somewhat - early MOSFETs had high RDSon and wasted more power when switched on hard, than did transistors.
In the interim, they developed the IGBT, it has a MOSFET input and a bipolar output, its basically a hybrid Sziklai pair and the bipolar output is an emitter follower - that makes them relatively slow, so you're basically exchanging conduction losses for switching losses.
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Not sure how early obsolete high resistance MOSFETs are pertinent to this discussion. Modern MOSFETs can be readily found with a few milliohms of ON resistance, giving much less ON voltage drop as compared to BJTs.
IGBT's are not only slow, but have a high ON voltage drop, similar to a Darlington, thus aren't efficient for switching low voltages.
The technology has made leaps & bounds - but high voltage ones are still more expensive.If you check suppliers, such as Digikey, you should find many MOSFETs with ON resistance of less than 100 milliohms for less than $1US.
Which is generally true for any transistor type.The technology has made leaps & bounds - but high voltage ones are still more expensive.
Your point?Which is generally true for any transistor type.
I think the answer is because it helps the booster to save you power?Why we use MOSFET and variable resistor in a buck boost converter ?
What are the benefits by using these components ?
You stated that "high voltage ones" (meaning MOSFETs) are more expensive. My "point" was that it's not unusual for transistors, whether MOSFETS, IGBTs or BJTs to increase in price with voltage.Your point?
When CRTs reigned supreme, sheer volume of production made bipolar transistors up to about 2kV as cheap as chips.You stated that "high voltage ones" (meaning MOSFETs) are more expensive. My "point" was that it's not unusual for transistors, whether MOSFETS, IGBTs or BJTs to increase in price with voltage.
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