Advanced SPICE-Modeling of 4H-SiC MESFETs

A modified drain source current suitable for simulation program with integrated circuit emphasis （SPICE） simulations of SiC MESFETS is presented in this paper. Accurate modeling of SiC MESFET is achieved by introducing three parameters in Triquint＇s own model （TOM）. The model, which is single piece and continuously differentiable, is verified by measured direct current （DC） I-V curves and scattering parameters （up to 20 GHz）.

An insulated-gate bipolar transistor model based on the finite-volume charge method

A finite-volume charge method has been proposed to simulate PIN diodes and insulated-gate bipolar transistor(IGBT)devices using SPICE simulators by extending the lumped-charge method.The new method assumes local quasi-neutrality in the undepleted N^(-)base region and uses the total collector current,the nodal hole density and voltage as the basic quantities.In SPICE implementation,it makes clear and accurate definitions of three kinds of nodes—the carrier density nodes,the voltage nodes and the current generator nodes—in the undepleted N^(-)base region.It uses central finite difference to approximate electron and hole current generators and sets up the current continuity equation in a control volume for every carrier density node in the undepleted N^(-)base region.It is easy to increase the number of nodes to describe the fast spatially varying carrier density in transient processes.We use this method to simulate IGBT devices in SPICE simulators and get a good agreement with technology computer-aided design simulations.

Memristor-based hyper-chaotic circuit for image encryption

The memristor is a kind of non-linear element with memory function,which can be applied to chaotic systems to increase signal randomness and complexity.In this paper,a new four-dimensional hyper-chaotic system is designed based on a flux controlled memristor model,which can generate complex chaotic attractors.The basic dynamic theory analysis and numerical simulations of the system,such as the stability of equilibrium points,the Lyapunov exponents and dimension,Poincare maps,the power spectrum,and the waveform graph prove that it has rich dynamic behaviors.Then,the circuit implementation of this system is established.The consistency of simulation program with integrated circuit emphasis(SPICE)simulation and numerical analysis proves the ability to generate chaos.Finally,a new image encryption scheme is designed by using the memristor-based hyper-chaotic system proposed in this paper.The scheme involves a total of two encryptions.By using different security analysis factors,the proposed algorithm is compared with other image encryption schemes,including correlation analysis,information entropy,etc.The results show that the proposed image encryption scheme has a large key space and presents a better encryption effect.

A new LTPS TFT AC pixel circuit for an AMOLED

This work presents a new voltage programmed pixel circuit for an active-matrix organic light-emitting diode（AMOLED） display.The proposed pixel circuit consists of six low temperature polycrystalline silicon thinfilm transistors（LTPS TFTs）,one storage capacitor,and one OLED,and is verified by simulation work using HSPICE software.Besides effectively compensating for the threshold voltage variation of the driving TFT and OLED,the proposed pixel circuit offers an AC driving mode for the OLED,which can suppress the degradation of the OLED.Moreover,a high contrast ratio can be achieved by the proposed pixel circuit since the OLED does not emit any light except for the emission period.

A new AC driving circuit for a top emission AMOLED

A new voltage programmed pixel circuit with top emission design for active-matrix organic light- emitting diode （AMOLED） displays is presented and verified by HSPICE simulations. The proposed pixel circuit consists of five poly-Si TFTs, and can effectively compensate for the threshold voltage variation of the driving TFT. Meanwhile, the proposed pixel circuit offers an AC driving mode for the OLED by the two adjacent pulse voltage sources, which can suppress the degradation of the OLED. Moreover, a high contrast ratio can be achieved by the proposed pixel circuit since the OLED does not emit any light except for the emission period.