Explain the formation of parasitic BJT and parasitic diode in Power MOSFET.

2.6k views
Explain the formation of parasitic BJT and parasitic diode in Power MOSFET. Can parasitic diode be used in same power electronics applications?
by
recategorized

1 Answer

Answer :

Parasitic Diode:

The parasitic diode is in between drain and source. The MOSFET structure itself contains parasitic diode or body drain diode. This parasitic diode allows the reverse flow of current when the MOSFET is in off state. The figure shows the internal parasitic diode. This parasitic diode have slow switching characteristics as compare to MOSFET channel. The integral diode have slow reverse recovery characteristics. In parasitic diode, drain acts as cathode and source acts as the anode. The integral diode have pn-n+.


image


Use of parasitic diode:

This parasitic diode is useful in the flow of reverse current in the inverter with an inductive load.


image


Parasitic BJT:

MOSFET structure also have parasitic BJT. The figure shows parasitic BJT. The n-channel MOSFET will have npn parasitic transistor. The body region of MOSFET acts as the base of BJT, the source of MOSFET acts as an emitter, the drain of MOSFET as a BJT collector. Parasitic BJT operates in the cut-off region.

image

Like 0 like
by

Please log in or register to answer this question.

Related questions

144 views
why IGBT is preferred as a power switch over both power BJT and MOSFET?

Last Answer : Because it has a higher switching frequency and heat tolerance.

1 answer
994 views
Operating frequency of power MOSFET is higher than that of power BJT. Justify the statement.

Description : Operating frequency of power MOSFET is higher than that of power BJT. Justify the statement.

Last Answer : Power MOSFET have high turning on and turning off capability high switching speed of MOSFET is due to the high rate of change of drain voltage. The switching losses of power MOSFET ... lower frequency. Hence, operating frequency of power MOSFET is higher than that of power BJT.

1 answer
3.2k views
Which phenomenon is present in thyristors but absent in BJT, MOSFET and IGBT ?

Description : Which phenomenon is present in thyristors but absent in BJT, MOSFET and IGBT ? (A) forward conduction (B) latching (C) forward blocking (D) reverse breakdown

Last Answer : Which phenomenon is present in thyristors but absent in BJT, MOSFET and IGBT ? (A) forward conduction (B) latching (C) forward blocking (D) reverse breakdown

1 answer
459 views
Compare BJT, MOSFET and IGBT .

Description : Compare BJT, MOSFET and IGBT .

Last Answer : BJT MOSFET IGBT BJT is a current controlled device. MOSFET is a voltage controlled device. IGBT is a voltage controlled device. The input impedance of BJT is low. ... is minority carrier device. MOSFET is majority carrier device. IGBT is minority carrier device.

1 answer
148 views
why igbt is used instead of bjt and mosfet?

Last Answer : ON state losses of IGBT is less as compared to MOSFET and BJT.

1 answer
163 views
Justify the statement. Antiparallel diode is connected across MOSFET.

Description : Justify the statement. Antiparallel diode is connected across MOSFET.

Last Answer : In MOSFET current is flow from drain to source but when the load is inductive the current may flow in opposite direction. To avoid the opposite flow of current and to protect MOSFET the antiparallel diode is connected across MOSFET.

1 answer
564 views
Is the input impedance of MOSFET more than BJT and FET?

Description : Is the input impedance of MOSFET more than BJT and FET?

Last Answer : Yes, the input impedance of MOSFET more than BJT and FET.

1 answer
2.6k views
is IGBT costlier than BJT and MOSFET?

Last Answer : Yes IGBT is costlier than BJT and MOSFET.

1 answer
851 views
Justify. Power MOSFET is operated at high enough gate source voltage to minimize the conduction losses.

Description : Justify. Power MOSFET is operated at high enough gate source voltage to minimize the conduction losses. 

Last Answer : MOSFET is metal oxide field effect transistor. MOSFET is a voltage controlled device. MOSFET is majority carrier device. MOSFET are of two one is n-channel MOSFET and p-channel MOSFET. Gate, ... . Hence, power MOSFET is operated at high enough gate-source voltage to minimize the conduction losses.

1 answer
108 views
what is the value of Beta in power BJT?

Description : What is the value of Beta in power BJT?

Last Answer : The beta value in power BJT is 5 to 10.

1 answer
152 views
A certain power MOSFET has a maximum junction temperature specification of 1500o C, a junction-to-case

Description : A certain power MOSFET has a maximum junction temperature specification of 1500o C, a junction-to-case thermal resistance of 1.00 C/W, and a junction-to ambient thermal resistance of 600 C/W. If the ambient temperature is 300o C ... the device will be A) 1.52 W B) 1.72 W C) 1.92W D) 2.00 W

Last Answer : A certain power MOSFET has a maximum junction temperature specification of 1500o C, a junction-to-case thermal resistance of 1.00 C/W, and a junction-to ambient thermal resistance of  ... 300o C, then the maximum allowable power dissipation in the device will be 2.00 W 

1 answer
115 views
Why MOSFET is used for low power applications?

Last Answer : MOSFET have high current losses due to High on state resistance. Hence MOSFET is used for low power applications.

1 answer
296 views
Explain the on state losses in power BJT.

Description : Explain the on state losses in power BJT.

Last Answer : On state losses in power BJT: Transistor have four types of losses one is turn on state losses second is turn off state losses third is turn on switching losses and fourth is turn ... ON = VCE sat x IC With increasing collector current collector to emitter saturation voltage increases.

1 answer
264 views
Explain open emitter BJT drive circuit.

Description : Explain open emitter BJT drive circuit.

Last Answer : open emitter BJT drive circuit:

1 answer
555 views
What is the difference between beta and forced beta for BJT?

Description : What is the difference between beta and forced beta for BJT?

0 answers
76 views
Explain switching model of MOSFET.

Description : Explain switching model of MOSFET.

0 answers
354 views
Explain MOSFET gate drive circuit and totem pole configuration.

Description : Explain MOSFET gate drive circuit and totem pole configuration.

Last Answer : MOSFET gate drive circuit: The turning on and turning off of MOSFET can be controlled from gate to source voltage signal. If the gate to source voltage of MOSFET exceeds threshold ... this configuration, the two switches (transistors) are used in totem pole arrangement with a comparator.

1 answer
566 views
Explain difference between enhancement MOSFET and depletion type MOSFET.

Description : Explain difference between enhancement MOSFET and depletion type MOSFET.

Last Answer : In enhancement MOSFET channel is not initially exists but in depletion MOSFET channel is already exists. In case of depletion MOSFET if the voltage is applied between drain and source the drain current will flow ... a channel. depletion MOSFET & enhancement MOSFET

1 answer
545 views
Explain the series and parallel operation of MOSFET. Which is suitable and why ?

Description : Explain the series and parallel operation of MOSFET. Which is suitable and why?

Last Answer : Series operation of MOSFET: To increase voltage handling capability MOSFETs are connected in series. When the MOSFETs are connected in series each MOSFET should turn on and turn off ... on and turn off time and transconductance. Each MOSFET should share current equally.  

1 answer
3.6k views
Describe with neat sketch the construction and working principle of MOSFET.

Description : Describe with neat sketch the construction and working principle of MOSFET.

Last Answer : Construction and working principle of MOSFET:  A) Depletion type MOSFET: Construction: The N-channel depletion type MOSFET is formed on P-type silicon substrate with two heavily ... accumulation of electrons and hence more current. Thus the MOSFET is a gate voltage controlled device.

1 answer
93 views
State the applications of MOSFET

Description : State the applications of MOSFET

Last Answer : Applications of MOSFET: i) Switching-mode-power-supplies (SMPS) and linear power supplies. ii) Brushless DC motor drives iii) Solid state DC relay iv) Automobile applications v) Stepper motor controller vi) Lighting controls vii) Solenoid drivers viii) Robotics ix) Induction heating

1 answer
329 views
The threshold voltage of an n- channel enhancement mode MOSFET is 0.5V when the device is biased at

Description : The threshold voltage of an n- channel enhancement mode MOSFET is 0.5V when the device is biased at a gate voltage of 3V. Pinch off would be occurs at a drain voltage of (A) 1.5V (B) 2.5V (C) 3.5V (D) 4.5V

Last Answer : The threshold voltage of an n- channel enhancement mode MOSFET is 0.5V when the device is biased at a gate voltage of 3V. Pinch off would be occurs at a drain voltage of 2.5V

1 answer
304 views
parallel operation of mosfet can be done more easily as compared to thyristor. why?

Description : parallel operation of MOSFET can be done more easily as compared to thyristor. why?

Last Answer : Parallel operation of MOSFET can be done more easily as compared to thyristor because the resistance of MOSFET is increases with increase in temperature. MOSFET have the positive temperature coefficient. In ... the parallel operation of MOSFET can be done more easily as compared to the thyristor.

1 answer
193 views
what is depletion type MOSFET?

Description : What is depletion type MOSFET?..........

Last Answer : Depletion MOSFET: Depletion MOSFET is a MOSFET in which the channel already exists. If we apply a voltage between drain and source then the drain current will flow even if the gate to source ... in figure. The drain current will be reduced as the gate to source voltage made more negative.

1 answer
183 views
what is enhancement MOSFET?

Description : What is enhancement MOSFET?...............

Last Answer : Enhancement MOSFET: There are two types of MOSFET one is enhancement MOSFET and second is depletion MOSFET. In enhancement MOSFET channel is created by applying threshold voltage between gate and source ... mode. The enhancement MOSFET will not conduct if the gate to source voltage is zero.

1 answer
205 views
is mosfet current controlled device?

Last Answer : No, MOSFET is not the curent controlled device. The current between drain and source which is drain current is controlled by applying a voltage between gate and source hence MOSFET is a voltage controlled device. 

1 answer
177 views
why mosfet is voltage controlled device?

Last Answer : already answered here is mosfet current controlled device?

1 answer
116 views
why mosfet is used for high frequency?

Last Answer : MOSFET provides better efficiency at high frequency and its high speed switching losses are less hence MOSFET is used for high frequency.

1 answer
125 views
Write the function of freewheeling diode.

Description : Write the function of freewheeling diode.

Last Answer : Function of Freewheeling Diode (FWD): a) Freewheeling diode is used across inductive loads such as coils, dc motor armature etc. to prevent voltage spikes across these loads when the switching ... current is shifted from switching device, it is turned off easily and regain its blocking ability.

1 answer
129 views
What would cause a diode to fail?

Description : What would cause a diode to fail?

Last Answer : Supply voltage beyond its limit

1 answer
2.6k views
Can we use a zener diode as a rectifier?

Description : Can we use a zener diode as a rectifier?

Last Answer : Yes we can use zener diode as rectifier but it have limitations better to use normal diode. Zener diode have some different applications.

1 answer
121 views
What is the use of Schottky diode?

Description : What is the use of Schottky diode?

Last Answer : Schottky diode are use in SMPS, Sample and hold circuits and voltage clamping etc.

1 answer
103 views
What is the use of laser diode?

Description : What is the use of laser diode?

Last Answer : laser diodes are use in telecommunication, rangefinders, barcode readers etc.

1 answer
93 views
What does a Shockley diode do?

Description : What does a Shockley diode do?

Last Answer : It is diode have low forward voltage drop and very high switching action

1 answer
103 views
What is the use of fast recovery diode?

Description : What is the use of fast recovery diode?

Last Answer : Fast recovery diode are used in high frequency rectification. Fast recovery diode also used for freewheeling. Fast recovery diode also used for DC to DC converter.

1 answer
152 views
What is the use of Tunnel diode ?

Description : What is the use of Tunnel diode ?

Last Answer : Tunnel diode is use in frequency converters and detectors, ultra high speed switching, amplifiers, etc.

1 answer
82 views
what does schottky diode do?

Last Answer : It is semiconductor diode with a low forward voltage drop and very high switching action

1 answer
270 views
why is zener diode heavily doped?

Last Answer : PN junction of zener diode is heavily doped than ordinary diode. For the occurrence of Zener effect the zener diode is heavily doped. If the zener diode is not heavily doped then Zener effect ... breakdown voltage is sharp. If the diode is lightly doped the diode will have higher breakdown voltage.

1 answer
787 views
does dynamic impedance zener diode vary?

Last Answer : Yes dynamic impedance of zener diode vary.

1 answer
112 views
does zener diode regulate voltage?

Last Answer : Yes, Zener diode is a voltage regulator. Zener diode maintain constant reverse Biased Voltage. If the current is varying then also zener diode maintain constant voltage.

1 answer
157 views
can zener diode be used in forward bias?

Last Answer : Yes it can be, and it will act like a normal PN junction diode. The characteristic of ZENER diode is exactly same as PN junction diode in forward Bias.

1 answer
277 views
State 2 advantages of JFET over BJT.

Description : State 2 advantages of JFET over BJT.

Last Answer : Advantages of JFET over BJT: 1) High input impedance 2) Better thermal stability 3) Produce less noise 4) Smaller than BJT 5) Rugged in construction and simpler to fabricate 6) High degree of isolation between Input and Output. 

1 answer
153 views
List specification of BJT.

Description : List specification of BJT.

Last Answer : * The bipolar junction transistor (BJT) has small signal current gain, α (hfb). * Maximum collector current Ic (max). * Maximum collector to emitter voltage, VCE (max). * Collector to emitter ... . * Collector to emitter cut off voltage, VCEO. * Base emitter saturation voltage, VBE (sat).

1 answer
5.1k views
State reason BJT is called as bipolar junction transistor.

Description : State reason BJT is called as bipolar junction transistor.

Last Answer : BJT is called bipolar junction transistor because in BJT current conduction takes place due to majority as well as minority charge carriers.

1 answer
75 views
List configurations of BJT.

Description : List configurations of BJT. 

Last Answer : Configurations of BJT : 1) Common Base (CB) configuration 2) Common Emitter (CE) configuration 3) Common Collector (CC) configuration

1 answer
285 views
State the need of biasing of BJT.

Description : State the need of biasing of BJT.

Last Answer : Need of biasing: The basic need of transistor biasing is to keep the base-emitter (B-E) junction properly forward biased and the collector-emitter (C-E) junction properly reverse biased ... transistor biasing is necessary for normal and proper operation of transistor to be used for amplification. 

2 answers
805 views
Draw circuit diagram of voltage divider biasing list two advantages of voltage divider biasing of BJT.

Description : Draw circuit diagram of voltage divider biasing list two advantages of voltage divider biasing of BJT.

Last Answer : Two advantages of voltage divider biasing of BJT. 1. It is very simple method of transistor biasing. 2. The biasing conditions can be very easily set. 3. there is no loading of ... 5. The resistor RE introduces a negative feedback. So all the advantages of negative feedback are obtained. 

1 answer
71 views
Compare BJT with FET

Description : Compare BJT with FET

Last Answer : FET BJT It is unipolar device i.e. current in the device is carried either by electrons or holes It is bipolar device i.e. current in the device is carried either by ... from minority- carrier storage effects & therefore has lower switching speeds & cut-off frequencies. 

1 answer
763 views
Compare between BJT and FET on the basis of (i) Biolar/Unipolar (ii) Tharmal Runaway (iii) Noise (iv) Applications

Description : Compare between BJT and FET on the basis of (i) Biolar/Unipolar (ii) Tharmal Runaway (iii) Noise (iv) Applications

Last Answer : Parameter BJT FET Bipolar/Unipolar It is bipolar device i.e. current in this device is carried by electrons and holes. It is unipolar device i.e. current ... in oscilloscopes, electronic voltmeters and other measuring and testing equipment because of their high input impedance.

1 answer
197 views
If the base current of a BJT is 250 µA and emitter current is 15 mA, then the common base current gain will be

Description :  If the base current of a BJT is 250 µA and emitter current is 15 mA, then the common base current gain will be A) 0.98 B) 0.41 C) 59 D) 55  

Last Answer :  If the base current of a BJT is 250 µA and emitter current is 15 mA, then the common base current gain will be 0.98 

1 answer
...