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The below Table shows the specification required for a gate drive circuit and the driven

MOSFETs in a buck converter. Answer the following Questions

下表は,降圧チョッパ回路に用いるゲートドライブ回路と駆動される MOSFET の仕様である。 以

下の問に答えよ。

DC input voltage

DC output voltage

DC output current

Switching frequency

Gate resistor

Gate driving voltage

Drain-to-source voltage

Drain current

On-state resistance

Forward transfer conductance

Threshold voltage

E

Vout

Lout

R₂

E

Vds

Is

Ran

US

Vih

Cias

Input capacitance

Cos

Output capacitance

Reverse transfer capacitance Cras

100 V

50 V

10 A

20 kHz

10 Ω

+10 V

250 V

30 A

100 m

20 S

5 V

10,000 pF

1000 pF

100 pF

1. Find the rise time Tr and the fall time Tf.

上昇時間 Tr と降下時間 Tf を求めよ。

2. Find the di/dt across the MOSFET in turn-on and turn-off transitions.

MOSFET がターンオン・ターンオフする際の di/dt を求めよ。

3. It is requested to reduce the dv/dt to a half in a turn-on transition without any change in the

turn-off transition. Answer the possible ways.

ターンオフ時には影響を与えずに, ターンオン時のdv/dt を2倍にしたい。 可能な方法を答え

よ。

Fig: 1


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