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Ideal Semiconductor Switch

Ideal Semiconductor Switch

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Semiconductors / Fundamental Components

Description

The Ideal Semiconductor Switch block models an ideal semiconductor switching device.

The figure shows a typical i-v characteristic for an ideal semiconductor switch.

If the gate-cathode voltage exceeds the specified threshold voltage, the ideal semiconductor switch is in the on state. Otherwise the device is in the off state.

In the on state, the anode-cathode path behaves like a linear resistor with on-resistance Ron.

In the off state, the anode-cathode path behaves like a linear resistor with a low off-state conductance Goff.

Using the Integral Diode tab of the block dialog box, you can include an integral cathode-anode diode. An integral diode protects the semiconductor device by providing a conduction path for reverse current. An inductive load can produce a high reverse-voltage spike when the semiconductor device suddenly switches off the voltage supply to the load.

The table shows you how to set the Integral protection diode parameter based on your goals.

GoalValue to SelectBlock Behavior
Prioritize simulation speed.Protection diode with no dynamicsThe block includes an integral copy of the Diode block. The block dialog box shows parameters relating to the Diode block.
Precisely specify reverse-mode charge dynamics.Protection diode with charge dynamicsThe block includes an integral copy of the Commutation Diode block. The block dialog box shows parameters relating to the Commutation Diode block.

Parameters

Main Tab

On-state resistance

Anode-cathode resistance when the device is on. The default value is 0.001 Ohm.

Off-state conductance

Anode-cathode conductance when the device is off. The value must be less than 1/R, where R is the value of On-state resistance. The default value is 1e-6 1/Ohm.

Threshold voltage, Vth

Gate-cathode voltage threshold. The device turns on when the gate-cathode voltage is above this value. The default value is 0.5 V.

Integral Diode Tab

Integral protection diode

Specify whether the block includes an integral protection diode. The default value is None.

If you want to include an integral protection diode, there are two options:

  • Protection diode with no dynamics

  • Protection diode with charge dynamics

Parameters for Protection diode with no dynamics

When you select Protection diode with no dynamics, additional parameters appear.

 Additional Parameters for Protection diode with no dynamics

For more information on these parameters, see Diode.

Parameters for Protection diode with charge dynamics

When you select Protection diode with charge dynamics, additional parameters appear.

 Additional Parameters for Protection diode with charge dynamics

For more information on these parameters, see Commutation Diode.

Ports

This figure shows the block port names.

G

Port associated with the gate terminal. You can set the port to either a physical signal or electrical port.

A

Electrical conserving port associated with the anode terminal.

K

Electrical conserving port associated with the cathode terminal.

Introduced in R2013b

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