What is a voltage regulator diode, and what is the difference between a voltage regulator diode and a regular rectifier diode?

Zener diode is a common electronic component that can stabilize the voltage within a certain range, enabling the circuit to operate normally. Zener diodes are widely used in power supplies, amplifiers, computers, communications, and other fields, and are an indispensable part of modern electronic technology. This article will provide a detailed introduction to the working principle, types, parameter selection, and applications of voltage regulator diodes.

1、 The working principle of voltage regulator diode

Zener diode is a semiconductor device with PN junction structure, and its working principle is similar to that of ordinary diodes. Under forward voltage, the current of the voltage regulator diode is linearly related to the voltage, while under reverse voltage, the current of the voltage regulator diode changes exponentially. Therefore, the voltage regulator diode can achieve voltage stability through reverse voltage.

The working principle of a voltage regulator diode can be simply divided into two stages: forward conduction and reverse cutoff.

1. Positive conduction stage

When the forward voltage of the voltage regulator diode reaches a certain value, the carriers in the PN junction begin to diffuse towards the opposite side, forming a forward current. At this stage, the current of the voltage regulator diode is linearly related to the voltage, and its current magnitude is limited by the external circuit.

2. Reverse cut-off stage

When the reverse voltage of the voltage regulator diode reaches a certain value, the electrons and holes in the PN junction are separated by the reverse electric field, forming a space charge region. At this time, the current of the voltage regulator diode drops sharply and remains at a small value. At this stage, the current of the voltage regulator diode is almost unaffected by external circuits, and the magnitude of its reverse current is determined by the characteristics of the device itself.

2、 Types of voltage regulator diodes

There are currently three common types of voltage regulators on the market: Zener diodes, LED voltage regulators, and TVS diodes.

1. Zener diode

A Zener diode is a diode with special voltage current characteristics that can stabilize voltage within a certain range. The working principle of a Zener diode is similar to that of a regular diode, but its voltage current characteristic is inverted U-shaped, meaning that within a certain voltage range, its current increases very little, thus achieving voltage stabilization.

2. LED voltage regulator diode

LED voltage regulator diode is a new type of voltage regulator device, and its working principle is similar to that of ordinary LED. The characteristics of LED voltage regulator diodes are high voltage regulation accuracy and low noise level, which can be applied in high-precision circuits.

3. TVS diode

TVS diode is a semiconductor device with special voltage current characteristics, which can protect other devices from overvoltage damage in the circuit. The working principle of TVS diode is to utilize the characteristic of reverse breakdown. When overvoltage occurs in the circuit, the TVS diode will quickly become conductive and absorb the overvoltage.

3、 Parameter selection of voltage regulator diode

When choosing a voltage regulator diode, the following parameters need to be considered:

1. Stable voltage

Stable voltage refers to the stable value of a voltage regulator diode under reverse voltage, also known as Zener voltage. The selection of stable voltage should be determined based on the voltage required by the circuit, generally choosing a stable voltage slightly higher than the voltage required by the circuit.

2. Maximum reverse current

The maximum reverse current refers to the maximum allowable current of a voltage regulator diode under reverse voltage, exceeding this value can cause device damage. Generally, the maximum reverse current that is slightly higher than the maximum operating current of the circuit should be selected.

3. Temperature coefficient of current

The current temperature coefficient refers to the relationship between the current and temperature of a voltage regulator diode. Generally, choosing a voltage regulator diode with a low temperature coefficient can reduce the impact of temperature changes on the circuit.

4. Appearance size

The external dimensions refer to the external dimensions and pin arrangement of the voltage regulator diode. When selecting, it should be determined based on the board layout of the circuit.

4、 Application of voltage regulator diode

Zener diodes are widely used in power supplies, amplifiers, computers, communications, and other fields. Here are some common application scenarios:

1. Voltage stabilizing power supply

Zener diodes can be applied in linear regulated power supplies to achieve stable control of output voltage. Stabilized power supplies are widely used in various electronic devices, such as computers, communication equipment, audio equipment, etc.

2. Reference voltage source

Zener diodes can be used in reference voltage sources to achieve precise control of the reference voltage in circuits. Reference voltage sources are widely used in fields such as analog circuits and sensors.

3. Voltage limiter

Zener diodes can be used in voltage limiters to protect other components in the circuit from damage caused by overvoltage. Voltage limiters are widely used in fields such as automotive electronics and power electronics.

4、 Faults and Solutions of Zener Diodes

1. Short circuit fault

Zener diode short circuit fault refers to a low resistance short circuit phenomenon between the input and output of the Zener diode. When such a fault occurs, the voltage regulator diode cannot function properly.

Solution: Check if the pins of the voltage regulator diode are short circuited, and if the load on the output terminal of the voltage regulator diode is too large, causing the voltage regulator diode to be unable to withstand excessive load current. If the voltage regulator diode is damaged, it needs to be replaced with a new one.

2. Open circuit fault

The open circuit fault of a voltage regulator diode refers to the phenomenon of a high resistance open circuit between the input and output of the voltage regulator diode. When such a fault occurs, the voltage regulator diode cannot function properly.

Solution: Check if the pins of the voltage regulator diode have poor contact, and if the voltage regulator diode has been damaged internally due to static electricity. If the voltage regulator diode is damaged, it needs to be replaced with a new one.

3. Voltage drift fault

Voltage drift fault of voltage regulator diode refers to the phenomenon that the output voltage of voltage regulator diode changes with time. When such a fault occurs, the voltage regulator diode cannot stably output a certain DC voltage normally.

Solution: Check if the voltage regulator diode has been subjected to excessive temperature or voltage shock, causing internal damage. If the voltage regulator diode is damaged, it needs to be replaced with a new one.

4. Overheating fault

Zener diode overheating fault refers to the phenomenon where the temperature of the Zener diode is too high during operation, resulting in a decrease or damage to its performance.

Solution: Check the heat dissipation of the voltage regulator diode. If the voltage regulator diode is subjected to excessive load current or high ambient temperature, it is necessary to strengthen the heat dissipation measures. If the voltage regulator diode has been affected by excessive temperature, a new voltage regulator diode needs to be replaced.

5、 The difference between voltage regulator diode and ordinary rectifier diode

1. Definition

Zener diode is a special type of diode that has the characteristic of stabilizing the output voltage. Its working principle is to stabilize the input voltage and output it as a certain DC voltage through the internal circuit of the chip. Zener diodes are commonly used in power circuits to ensure stable operation of the circuit.

A regular rectifier diode is a type of ordinary diode whose main function is to convert alternating current into direct current. Its working principle is to utilize the unidirectional conductivity of diodes to convert the voltage of the positive or negative half cycle into direct current through the forward conduction or reverse cutoff of the diode.

2. Structure

The basic structure of voltage regulator diodes and ordinary rectifier diodes is composed of P-type and N-type semiconductor materials. However, the internal structure of the voltage regulator diode is relatively complex, and its chip is composed of multiple PN junctions, metal connection lines, and other materials. The structure of ordinary rectifier diodes is relatively simple, usually with only one PN junction and two pins.

3. Job characteristics

The main characteristics of a voltage regulator diode are its fixed output voltage and high stability. Its output voltage can be adjusted within a certain range, usually at common voltage values such as 3.3V, 5V, 12V, etc. Zener diodes can automatically adjust the output voltage when the input voltage changes, maintaining stable operation of the circuit.

The main characteristic of ordinary rectifier diodes is their unidirectional conductivity, with a voltage drop of around 0.7V when conducting in the forward direction and a very high resistance when turning off in the reverse direction. Ordinary rectifier diodes are commonly used in circuits for rectifying power supplies, reverse protection, and other purposes.

4. Application

Zener diodes are commonly used in power circuits to provide stable voltage to the downstream circuit. The advantages of a voltage regulator diode are stable output voltage, high accuracy, and fast response speed. Zener diodes can be applied to various electronic devices, such as computers, televisions, mobile phones, power tools, etc.

Ordinary rectifier diodes are commonly used in power supply circuits, protection circuits, and other aspects. The advantages of ordinary rectifier diodes are simple structure, low price, and wide use. Ordinary rectifier diodes can be applied to various electronic devices, such as household appliances, automotive electronics, communication equipment, etc.

5. Choose

When choosing between a voltage regulator diode and a regular rectifier diode, it is necessary to select the appropriate device according to the requirements of the actual application. If stable output voltage is required, a voltage regulator diode can be chosen; If you need to convert AC power to DC power, you can choose a regular rectifier diode.

Of course, when selecting devices, specific parameters such as maximum leakage current, forward conduction voltage, and reverse breakdown voltage need to be considered. Different devices have different parameter characteristics and need to be selected according to specific application requirements.

In short, voltage regulator diodes are an indispensable part of electronic technology and play an important role in various electronic devices. The solution to the fault of the voltage regulator diode mainly includes checking the pin contact, checking the load, and replacing the voltage regulator diode with a new one. When using a voltage regulator diode, attention should be paid to its working conditions to avoid being affected by excessive voltage or temperature, in order to ensure its normal operation. Although the appearance of a voltage regulator diode is similar to that of a regular rectifier diode, there are significant differences in their functions and working principles. In practical applications, suitable devices need to be selected according to specific requirements.