The rectifier is a circuit that contains a diode. It is sometimes referred to as a rectifier diode for this reason. There are several P-N junction diodes, but the simplest one is the rectifier diode.
The rectifier is described as simple because it is only used by a full bridge rectifier and a half-bridge rectifier for rectifying an AC signal. Since it can carry a higher current than many other diodes, rectification is made possible. A rectifier diode has a high break down voltage of between 200 volts and 1,000 volts. Its forward voltage drop is anywhere from 0.70 volts to 0.90 volts.
The Schottky diode is different than the rectifier diode because the Schottky diode uses a junction in the middle of a metal plate and N-type semiconductor. The Schottky diode is commonly referred to as a barrier diode. Most low voltage circuits will contain a Schottky diode because of its forward voltage drop being under the drop of the rectifier diode. Instead of the forward voltage drop being between 0.70 volts and 0.90 volts, the Schottky diode’s forward voltage drop is anywhere from 0.25 volts to 0.50 volts.
Let’s go over a list of differences between the rectifier diode and the Schottky diode.
- You can use rectifier diodes with high-frequency applications.
- Rectifier diodes get more reverse recovery loss and reverse recovery time.
- The forward voltage drop is higher compared to the Schottky diode.
- It is a PN junction diode because of the junction that forms between the P-type semiconductor and the N-type semiconductor.
- Schottky diodes are used in SMPS circuits and other high-frequency applications.
- You get much less reverse recovery loss and reverse recovery time with Schottky diodes.
- The forward voltage drop is considerably lower compared to the Schottky diode.
- The junction is produced between the metal plate and the N-type semiconductor.
What Makes the Schottky Diode Unique?
The Schottky diode is a unipolar device because it has electrons that serve as major carriers on each side of the junction. A depletion layer does not exist next to the junction, which means there is less of a forward voltage drop. That doesn’t mean there is no forward voltage drop, but it is considerably less than the rectifier diode’s forward voltage drop. The current conduction takes place because of the electrons moving around. The opposite direction does not have any holes.
There is no reverse leakage current with a Schottky diode. During a reverse-biased state, the current flow goes from the cathode to the anode. The electric hole recombination won’t have as much of a delay from this either. As a result, it is much faster for the Schottky diode to switch between on and off when compared to the PN junction diode.
During a forward bias state of the Schottky diode, the N layer conduction electrons receive a lot of energy to travel through the junction in order to reach the metal. Because of all the energy needed for the electrons to push their way into the metal, they are referred to as hot carriers. Whenever you have a Schottky barrier diode, think of it as a hot carrier diode.
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When you choose between a Schottky diode and a rectifier diode, think about what you’re using it on. Do you need to switch power supplies? Do you need to use the diode on radars or other sensitive communication receivers? Do you need to use it in computer gating or clipping circuits? Most importantly, will you be developing integrated circuits for fast digital location apps?
If you answered “no” to all these questions, then you’re better off with the rectifier diode. But if you answered “yes,” then go with the Schottky diode instead.