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When more accuracy is desired in modelling the diode's turn-on characteristic, the model can be enhanced by doubling-up the standard PWL-model. This model uses two piecewise-linear diodes in parallel, as a way to model a single diode more accurately. PWL Diode model with 2 branches. The top branch has a lower forward-voltage and a higher ...
In VHDL-AMS, a design consists at a minimum of an entity which describes the interface and an architecture which contains the actual implementation. In addition, most designs import library modules. Some designs also contain multiple architectures and configurations. A simple ideal diode in VHDL-AMS would look something like this:
Semiconductor device modeling creates models for the behavior of semiconductor devices based on fundamental physics, such as the doping profiles of the devices. It may also include the creation of compact models (such as the well known SPICE transistor models), which try to capture the electrical behavior of such devices but do not generally ...
The circuit is treated as a completely linear network of ideal diodes. Every time a diode switches from on to off or vice versa, the configuration of the linear network changes. Adding more detail to the approximation of equations increases the accuracy of the simulation, but also increases its running time.
Mixed-mode simulation is handled on three levels: with primitive digital elements that use timing models and the built-in 12 or 16 state digital logic simulator, with subcircuit models that use the actual transistor topology of the integrated circuit, and finally, with inline Boolean logic expressions.
The Shockley equation doesn't model this, but adding a resistance in series will. The reverse breakdown region (particularly of interest for Zener diodes) is not modeled by the Shockley equation. The Shockley equation doesn't model noise (such as Johnson–Nyquist noise from the internal resistance, or shot noise).
Diode logic (or diode-resistor logic) constructs AND and OR logic gates with diodes and resistors. An active device ( vacuum tubes with control grids in early electronic computers , then transistors in diode–transistor logic ) is additionally required to provide logical inversion (NOT) for functional completeness and amplification for voltage ...
In normal operation the base-emitter junction does indeed form a diode, but in most cases it is undesirable for the base-collector junction to behave as a diode. If a sufficient forward bias is placed on this junction it will form a parasitic diode structure, and current will flow from base to collector.