Dynex Semiconductor AN5001 Application Note Vt and r on-state Characteristic Model

About this manual

The document discusses how traditional straight-line models using coefficients Vt (threshold voltage) and r (dynamic resistance) can lead to incorrect assumptions when calculating power loss in power semiconductor devices. It highlights that while these terms originated from pre-computer calculation methods, modern computing allows for better approximations of the device's forward volt drop curve.

What's inside

• Use Of The Vt And r On-state Characteristic Model
• Definitions Of Vt And r Variations
• Limitations Of The Vt R Model
• A Four Coefficient Model
• Power Assembly Capability

Frequently asked questions

What is the limitation of using the Vt and r model for power loss calculation?

Using this model can lead to many incorrect assumptions because it only gives correct values at one or two points on the curve, resulting in optimistic or pessimistic answers depending on where the point is taken.

Where can users find the specific values for coefficients A, B, C, and D?

Dynex Semiconductor has determined these values for various device types, which are listed in Table 2 (for thyristors) and Table 3 (for diodes).