Piecewise Linear MOSFET

Description

This MOSFET model is developped with two key objectives:

1. Accuracy and Computational Efficiency: The model accurately simulates both switching and static behaviors of MOSFETs and is optimized for fast simulation.
2. Robustness and Characterization: It is designed to be robust and can be easily characterized using standard datasheet.

This MOSFET model incorporates:

• Three nonlinear capacitances $C_{GD}$, $C_{GS}$, and $C_{DS}$ characterized by Capacitance-$V_{DS}$ matrices, modeling $C_{ISS}$, $C_{OSS}$, and $C_{RRS}$ respectively.
• A PWL Diode representing the MOSFET body diode, characterized by a Voltage-Current data matrix.
• An internal piecewise linear MOSFET model using 3D Triangular meshing for output and transfer characteristics (details below).
• An internal gate resistance $R_G$.

Capacitances

The capacitances are calculated as follows:

$$C_{GS} = C_{ISS} - C_{RSS}$$

$$C_{DS} = C_{OSS} - C_{RSS}$$

$$C_{GD} = C_{RSS}$$

Capacitance Consistency

It is recommended that all three capacitances share the same $V_{DS}$ values. If not, interpolation is used to calculate missing $V_{DS}$ values.

Capacitance Options

Alternatively, a single capacitance value can be used to model a $V_{DS}$-independent capacitance.

Body Diode

To accurately model the diode's off state, include at least one data point with a negative voltage in the characteristics matrix. In most cases, modeling avalanche breakdown is unnecessary.

MOSFET Equations

The internal MOSFET model employs the following drain current equations:

Optimization techniques are employed to derive $V_{th}$, $\lambda$, and $K$ from the output and transfer characteristics data. DIRECT (DIviding RECTangles) algorithm is used for this optimization, as described in:

• D. R. Jones, C. D. Pertunen, and B. E. Stuckmann, "Lipschitzian optimization without the lipschitz constant," J. Optimization Theory and Applications, vol. 79, p. 157 (1993).

Beta Status

The Piecewise Linear MOSFET model is currently in Beta. It is not advised for production use. For issues, contact support@simba.io or file an issue on Github. A list of known issues can be found here.

Library

Electrical > Semiconductors

Pins

Name	Description
Drain	Drain
Source	Source
Gate	Gate (Control Input)

Parameters

Name	Description
Rg	Gate Internal Resistance value, in Ohm
VgsIdMatrix	Transfer Characteristic
VgsIdMatrix_Vds	Transfer Characteristics Vds
VdsIdMatrix	Output Characteristics
VdsIdMatrix_Vgs	Output Characteristics Vgs
Ciss	Input Capacitance, in F
Coss	Output Capacitance
Crss	Reverse Transfer Capacitance
Vsd_Is_BodyDiodeMatrix	Source Drain current vs Source-Drain Voltage (Body Diode)