2 March 2018

Compare Power Transistor and Power MOSFET

Power MOSFET

  • The MOSFET is a majority charge carrier device. 
  • It is a voltage controlled device. The input voltage controls the output current therefore It is a characterized by transconductance. 
  • The input drive circuit of MOSFET is much simpler than the transistor due to high input impedance. 
  • It has a positive temperature co – efficient of the resistance. 
  • The secondary breakdown and hot spot does not occurs in the MOSFET. 
  • The gate current for the conduction of MOSFET requires only for short duration in order to charge and discharge of self capacitance. 
  • The MOSFET has no storage and delay time therefore its switching speed is higher than that of transistor. 
  • The transconductance of the MOSFET increases with increase in the current. 
  • The on state resistance of the MOSFET increases with increase in current as compared to transistor. 
  • The peak current as well as continuous current rating of MOSFET is higher than that of transistor therefore the junction temperature does not increases at higher current rating. 
  • The safe operating area of MOSFET is better than that of transistor. 
  • The conduction voltage of the MOSFET is higher than that of transistor and it increases as the voltage rating increases therefore the conduction losses in the MOSFET is higher than that transistor at rated current. 
  • The MOSFET is more efficient particularly at high frequency whereas it is less efficient at low frequency due to higher switching losses. 
  • The MOSFET is ruggedness, cost effective and reliable than transistor even at lower frequency operation. The MOSFET is less sensitive to voltage spike than transistor.


Power Transistor 

  • The transistor is a majority as well as minority charge carrier device. 
  • It is a current controlled device. The input current controls the output current therefore it is characterized by current gain. 
  • The transistor remains in on state if the base current continuously flows through it. 
  • It has a negative temperature co – efficient of the resistance. 
  • The secondary breakdown and hot spot may occurs in the transistor. 
  • The switching speed of the transistor is lower than that of MOSFET. 
  • The gain of the transistor decreases with increases in the current. 
  • The junction temperature of the transistor increases with peak and continuous current. 
  • The conduction losses in the transistor are lower than that of MOSFET due to low on state resistance. 
  • The switching losses in the transistor are lower at low frequency therefore it is suitable for lower frequency operation. 
  • The transistor is less sensitive to voltage spike than MOSFET.
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