Diode reverse recovery characteristics — SUNMATE

Diode reverse recovery characteristics

The ratio of these two time factors (i.e. T P and T d) is called the softness factor. In the case of a normal diode, the time taken for current attenuation (t d) will be shorter than the time taken for the current to reach its negative peak (T P). On the other hand, for soft recovery diodes, the opposite is true. That is, here, t d will be larger than t P. We can see that the softness factor can measure the loss during semiconductor conversion. The greater the proportion; The switching loss will be greater. It can be concluded that when we use soft recovery diodes, semiconductor switches experience more losses than ordinary diodes.

This reverse recovery phenomenon is basically a parasitic effect experienced in the case of diodes and is considered to depend on the doping level of silicon and its geometry. Moreover, even if the junction temperature, the rate of decrease of the forward current and the value of the forward current just before the reverse bias are applied, it is considered to affect its value. The longer the reverse recovery time; Diodes are slow and vice versa. Therefore, a diode with a small reverse recovery time is preferred, especially when a high switching speed is required. In addition, during this time interval, a large amount of current will return to the power supply to provide power to the diode. Therefore, the reverse recovery time of diode is an important design factor to be considered in the design of power supply.

February 1999: Intel releases Pentium III processor. Pentium III is a 1 × 1 square silicon, with 9.5 million transistors, using Intel 0.5 25 micron process technology.

At this time, you should understand that "1" and "0" are only two electrical signals, specifically two voltage values, which can control the on-off of the circuit.

This is just a simplified description. In fact, from the perspective of analog electricity, the requirements for on and off are forward bias and reverse bias of two PN sections, and the c-pole voltage should also be considered. However, in the actual digital circuit, the e-pole voltage and c-pole voltage are generally constant, either provided by the power supply or grounded, Therefore, we can simply remember that "the on-off of transistor circuit is determined by the comparison between b-pole voltage and constant e-pole voltage".

What elements are there in an ordinary circuit, but they are resistors, capacitors, inductors, diodes, triodes and other transistors. These circuits were first used in analog form, mainly to deal with continuously changing analog quantity. It amplifies (reduces) the analog quantity signal, performs certain operation processing on the signal, as well as oscillation and feedback, modulation circuit, filtering, demodulation circuit and so on. It should be said that the early circuits were analog circuits, especially when there were only resistors, capacitors and inductors.

The inspiration for this study comes from the famous "Moore's law". Moore's law was put forward by Gordon Moore, one of the founders of Intel, in the 1960s. It believes that the number of transistors on integrated circuits will double every two years. In order to follow the "golden rule" of the industry, researchers continue to try new methods to implant as many transistors as possible into computer microchips. The latest trend is to place three-dimensional transistors vertically. Through various efforts, tens of billions of transistors can finally be loaded on microchips the size of fingernails.