What Is Discrete Semiconductor?
Discrete Semiconductor is a type of semiconductor product. Also called individual semiconductors, they are semiconductors with a single function implemented on a single chip.
Discrete Semiconductors include diodes, transistors, thyristors, and many others. Modules that combine multiple discrete chips into a single package are also classified as Discrete Semiconductors.
On the other hand, in contrast to single-function discrete, semiconductor products in which multiple semiconductor elements are mounted on a single chip and multiple functions such as calculation and memory are implemented are called integrated circuits (IC).
Uses of Discrete Semiconductor
There are various types of Discrete Semiconductors, each of which is used in a wide range of fields.
Light-emitting elements such as light-emitting diodes are used in lighting, displays, backlights for electronic equipment, remote controls, etc. Light-receiving elements such as photodiodes and phototransistors are used in optical communication systems, spectrometers, automatic doors, sensors, etc.
Power semiconductors such as diodes, transistors, and thyristors control current and power. They are used in power supplies for communication equipment and OA equipment, power control for communication base stations and data centers, power conditioners for power plants, drive systems and vehicle control systems for railroads, and onboard power supplies and chargers for electric vehicles (EV). Power supplies and chargers for electric vehicles (EVs), etc.
Discrete Semiconductor Principles
The principle of operation of the main Discrete Semiconductors is as follows:
- Diode: A diode is an element that allows current to flow in only one direction.
When a positive forward voltage is applied to the P side and a negative forward voltage to the N side, excess free electrons from the N side move to the P side and holes from the P side move to the N side, where they combine and disappear at the junction surface.
At this time, electrons are supplied from the power supply to the N side, electrons flow out from the P side, and current flows from the P side to the N side; if a negative reverse voltage is applied to the P side and a positive voltage to the N side, no current flows because both free electrons and holes move to the opposite side from the junction plane. - Transistor: A transistor is a device with a switching function and comes in two types: NPN (N-channel) type and PNP (P-channel) type.
In the case of the N-channel type, when a voltage higher than the threshold voltage is applied between the P layer and the gate G connected via an insulating layer and the source S, the P layer flips to N, changing from the NPN structure to the NNN structure, and current flows. - Thyristor: Thyristor is a device with a rectifying function and has a PNPN 4-layer structure.
When a trigger signal is input to the gate and a forward voltage is applied between the anode and cathode, the thyristor turns on. Once on, the current continues to flow even if the gate signal is lost. When a reverse voltage is applied between the anode and cathode, the thyristor goes to an off state.
This principle is used to realize an operation in which an alternating current is applied between the anode and cathode to supply power for only half of an AC cycle.