Diodes From Basic Rectification To Advanced Transmission

Diodes from basic rectification to advanced transmission

As the most basic semiconductor device, diodes play a vital role in electronic technology. Whether it is a simple rectifier circuit or a complex photoelectric conversion system, diodes can be seen. This article will show the application of diodes in different fields and their importance through several specific application cases.

1. Application in rectifier circuits

Rectification is one of the most common diode applications, especially in power conversion equipment. The following is an actual rectifier circuit example to illustrate how diodes work.

Suppose there is a household appliance whose internal circuit requires a stable DC power supply. However, the mains power grid usually provides alternating current (AC), which requires a rectifier circuit to convert AC into direct current (DC).

The power module of this household appliance uses a bridge rectifier circuit, which contains four silicon rectifier diodes (such as 1N4001). These diodes are turned on in the positive half cycle of AC and cut off in the negative half cycle, thereby converting AC into unidirectional pulsating DC. After that, through capacitor filtering and smoothing circuits, a relatively smooth DC voltage is obtained to supply the subsequent circuit.

Choose the right diode: Choose the right rectifier diode model according to the maximum input voltage and average current of the circuit.

Thermal management: In high-power applications, it is necessary to consider the heat dissipation of the diode to avoid performance degradation or even damage due to overheating.

Filtering effect: By reasonably designing the capacity of the filter capacitor, the ripple component in the output voltage can be effectively reduced and the power quality can be improved.

2. Application of photodiodes in photoelectric sensors

Photodiodes are devices that can convert optical signals into electrical signals and are widely used in various optical measurement and sensing systems.

In automated production lines, photoelectric sensors are used to detect the position, color and other characteristics of objects. As the core component of photoelectric sensors, the performance of photodiodes directly affects the accuracy and reliability of the detection results.

The material detection system on a factory production line uses a reflective photoelectric sensor based on photodiodes. When an object passes through the detection area, the infrared light emitted by the sensor will be reflected back to the sensor by the object, and the photodiode receives the reflected light and converts it into a corresponding electrical signal. By analyzing these electrical signals, the control system can determine the existence of the object and its position information.

Sensitivity adjustment: By adjusting the gain of the photodiode or using diodes with different sensitivity levels, it can adapt to detection objects of different colors or reflectivity.

Anti-interference design: Considering that there may be multiple light source interferences in the production environment, the design of the sensor needs to have good anti-interference capabilities.

Signal processing algorithm: Use digital signal processing technology to amplify, filter and process the analog signal output by the photodiode to improve the detection accuracy.

3. Application of Schottky diodes in high-speed switching circuits

Schottky diodes are widely used in high-speed switching power supplies and inverters due to their low forward voltage drop and fast switching speed.

With the development of new energy vehicles, the requirements for on-board power conversion systems are getting higher and higher, which not only requires high energy conversion efficiency, but also requires stable operation of the system in high temperature environments.

A DC/DC converter of an electric vehicle uses Schottky diodes as auxiliary rectifying elements. Compared with ordinary silicon rectifier diodes, Schottky diodes generate less heat when forward-conducting, which helps to improve the overall efficiency of the converter. In addition, the fast switching characteristics of Schottky diodes also help to reduce electromagnetic interference and extend the life of the equipment.

Thermal design: Considering the various environmental conditions that may be encountered during the driving of the car, heat dissipation design is particularly important to ensure that the diode can still work normally under extreme temperatures.

Electromagnetic compatibility (EMC): Reduce the impact of noise generated by Schottky diodes during switching on other circuits by optimizing circuit layout and using appropriate filters.

Reliability assessment: Study the aging and failure mechanisms of Schottky diodes in practical applications to ensure their long-term reliability.

IV. Application of voltage regulator diodes (Zener diodes) in protection circuits

Zener diodes are often used in power protection circuits to prevent overvoltage from damaging sensitive devices due to their stable reverse breakdown characteristics.

In modern electronic devices, overvoltage may lead to serious consequences such as data loss or hardware damage. Therefore, effective voltage protection measures are essential.

A set of Zener diodes are integrated into the power management unit (PMU) of a server to prevent excessive voltage caused by power fluctuations or transient spikes. When the input voltage exceeds the Zener voltage, the Zener diode will turn on and shunt excess current, thereby protecting the back-end circuit from damage.

Selection principle: Select the appropriate Zener voltage and power level according to the maximum voltage and current requirements of the circuit.

Parallel use: For applications that require higher power protection, multiple Zener diodes can be connected in parallel to disperse heat.

Hot-swap design: For systems that require hot-swap functionality, the transient response characteristics of the Zener diode during the plug-in and plug-out process should be considered.

As one of the most basic and indispensable components in electronic circuits, diodes have a wide range of applications. From common power adapters in daily life to optoelectronic sensor systems in the high-tech field, diodes are silently contributing their strength. With the advancement of technology, the introduction of new materials and manufacturing processes will further expand the application boundaries of diodes, providing more possibilities for the development of future electronic devices.