After the invention of the first semiconductor device, many great scientists investigated the properties of the p-n junction. As you may have guessed, this is a common diode that can be seen in any electronic circuit. At the time of its invention, it was an element that made a real revolution and changed all ideas about the future of electronics. Also, the technology of its manufacture did not remain without attention. The Zenner and Gunn diode appeared. The Schottky diode was also invented,
possessing interesting properties. Its use in electronics was not as sensational as that of its famous "brothers". The special properties of this element were previously used in highly specialized schemes and did not find wide application. It is all the more interesting that recently the Schottky diode has begun to be used as the main element in switching power supplies. It works in almost all electronic household appliances: TVs, tape recorders, personal computers, laptops, etc. Special properties of the device are manifested in a low voltage drop at the p-n junction. It does not exceed 0.4 volts. That is, according to thisparameter, it is as close as possible to the ideal element that is used in the calculations. True, at a voltage of more than 50 volts, these properties disappear. But nevertheless, the Schottky diode has become widely used in circuits with operational amplifiers. The power supply of such circuits did not exceed 15 volts of direct voltage, which made it possible to take full advantage of the properties of this device. He could be in the feedback loop as a limiting element or participate in the work of the regulators.
In addition to such an important property as the voltage drop across the p-n junction, the Schottky diode has a small capacitance. This allows it to work in high frequency circuits. The almost “ideal” properties of this element do not distort the high frequency signal. That is why they began to put it in switching power supplies, communication devices and regulators. But besides the positive qualities, it is necessary to note the disadvantages. Schottky diodes are very sensitive even to a short-term excess of the reverse voltage from the permissible value. This leads to the failure of the element. Unlike its silicon counterparts, it does not recover. Thermal breakdown leads either to the appearance of leakage currents, or to the “transformation” of the device into a conductor.
The first malfunction will lead to the unstable operation of the entire electronic device. It is quite difficult to find and eliminate it. As for thermal breakdown, then, for example, in a switching power supply, this will lead to the operation of short circuit protection. After replacementdefective element, the power supply will work normally. Modern industry produces sufficiently powerful Schottky diodes. The pulse current in such devices can reach 1.2 kA. The constant operating current in some types reaches 120 A. Such devices have a wide current range and good performance characteristics. They are successfully used in household appliances and industrial electronics.
