Reverse Recovery Current of a diode

In summary, when a reverse bias voltage is suddenly applied to a diode in forward bias phase, the excess of minority charges stored in the P and N regions must be cleared out, causing a reverse current to appear before the diode is fully blocked. This current is a result of both diffusion and recombination, and explains why the current suddenly becomes negative.
  • #1
tonyjk
227
3
Hello,

When the diode is in forward bias phase and suddenly we apply a reverse bias voltage, the diode takes time to be fully blocked because of the excess of minority charges that are stored in P and N region. Thus a reverse current appears in the diode for a short time before it is blocked. My question is, is this current a diffusion of the excess of minority carriers that are stocked? If yes, why this happens physically speaking? How the current suddenly becomes negative?

Thank you
 
Physics news on Phys.org
  • #2
Hello again,

I am talking about this graph, which force is driving the excess of minority charges when the negative voltage is applied?
 

Attachments

  • diode graphs.png
    diode graphs.png
    13.3 KB · Views: 606
  • #3
Electric field force, F = qE. Minority carriers get stored in the depletion zone under forward bias. When the bias suddenly reverses, the E field of the external source points in a direction that forces the minority carriers back to their native material. Holes stored on the n side are forced to transit back to the p side and vice-versa. Similarly, electrons in the p side are forced back to the n side. Once the stored charge has been removed from the depletion zone and returned to its origin, the "tail current" ceases. Make sense?

Claude
 
  • #4
tonyjk said:
Hello,

When the diode is in forward bias phase and suddenly we apply a reverse bias voltage, the diode takes time to be fully blocked because of the excess of minority charges that are stored in P and N region. Thus a reverse current appears in the diode for a short time before it is blocked. My question is, is this current a diffusion of the excess of minority carriers that are stocked? If yes, why this happens physically speaking? How the current suddenly becomes negative?

Thank you
When the potential is reversed the minority charges must be cleared out. This occurs both by dffusion and by recombination (holes in the n region recombine with electrons in the n region, and likewise with electrons in the p region). The negative current denotes that the sense of flow is opposite to that during forward bias.
 

1. What is reverse recovery current of a diode?

The reverse recovery current of a diode is the current that flows in the reverse direction when the diode switches from forward bias to reverse bias. It is caused by stored charge in the diode's depletion region and can cause delays in switching and power losses.

2. Why is reverse recovery current important?

Reverse recovery current is important because it affects the performance and efficiency of diodes in electronic circuits. Excessive reverse recovery current can lead to voltage spikes, increased power dissipation, and decreased switching speed.

3. How is reverse recovery current measured?

Reverse recovery current can be measured using a current probe connected to an oscilloscope. The diode is subjected to a forward current and then a reverse voltage, and the resulting current waveform is observed to determine the peak reverse recovery current.

4. What factors affect reverse recovery current?

The main factors that affect reverse recovery current are the diode's construction, such as the size and doping levels of the depletion region, as well as the diode's operating conditions, such as temperature and applied voltage.

5. How can reverse recovery current be reduced?

Reverse recovery current can be reduced by using diodes with a lower capacitance and shorter depletion region, as well as by carefully selecting operating conditions and circuit design. Schottky diodes, which have a smaller depletion region, can also be used to reduce reverse recovery current.

Similar threads

  • Electrical Engineering
Replies
7
Views
2K
  • Electromagnetism
Replies
4
Views
4K
  • Electrical Engineering
Replies
8
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
1
Views
956
Replies
5
Views
2K
Replies
2
Views
1K
  • Atomic and Condensed Matter
Replies
3
Views
4K
  • Introductory Physics Homework Help
Replies
2
Views
984
  • Electrical Engineering
Replies
16
Views
6K
Back
Top