The Role Of Diodes In Voltage Reference Circuits

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When building electric circuits for your application, there are various parameters that you will try to focus on. One of them is the voltage reference. When we say that it is a voltage reference circuit, we are implying that the output voltage of that circuit does not go high or below the referenced figure no matter what. Not even external factors such as temperature frequency will affect the output voltage from this circuit. In other words, the circuit will have high power stability.

We cannot ignore the importance of stability when it comes to real-world applications. Electronic devices designed for sensitive applications need to have stable output voltage as it will determine their overall performance. Sensors that rely on voltage are perfect examples whereby a slight variation will affect the data that is collected by the sensor.

Voltage reference circuits come in different forms. The difference is mainly defined by the type of electronic component that is used to regulate the voltage and ensure that it does not go beyond the reference point.

Zener diode is one of the most common types of diodes that is used in voltage reference circuits. These diodes use Zener breakdown to ensure that the circuits operate and remain stable within the breakdown region. Each Zener diode that you are planning to use in the circuit should have a defined breakdown voltage which should also be suitable for the application area of the circuit.

Other than diodes, transistors are also used in voltage reference circuits. When a transistor is used with a diode they end up creating bandgap voltage reference circuits. Bipolar junction transistors are preferred for such applications mainly because of the high thermal stability that they offer. The fact that both transistors and diodes are made of semiconductor materials makes them better options.

Modern voltage reference circuits allow users to select the preferred reference voltage for the circuits. This is done by manually programming the circuits the adding controllers. This way, you can adjust the voltage depending on the needs of the application.

In this article, our focus will be on the diodes. We will look at the key roles that they play when they are used in the voltage reference circuits.

Zener diode working principle

The working principle of the Zener diode is based on the reverse biased whereby it will undergo a reverse breakdown. To be more specific, it is called a Zener breakdown and this is the reference voltage of the Zener diode. Otherwise, the breakdown voltage in other diodes is due to the impact of ionization.

When buying Zener diodes, there are several specifications that you should look at as they will determine the usability of the diode in the reference voltage. One of the key specifications is the reverse voltage. This one will directly determine the voltage reference in the circuit.

How are Zener diodes used in reference voltage circuits?

After knowing the working principle of Zener diodes, it will be easy to tell how they are connected to the reference voltage circuits. Here are some of the key roles that Zener diodes play in the reference voltage circuits:

Diodes provide the reference voltage

A key property of this circuit is to have a reference voltage. While there are many methods of ensuring that the diode achieves this, using diodes has proven to be the most reliable way. Zener diodes define the reference voltage of these circuits. This is achieved by the fact that you will get a diode that has a fixed voltage. When included in the circuit, that voltage will serve as a reference voltage. The output voltage will not go higher or lower than that of the diode. Also, the output voltage will always be constant hence guaranteeing the stability of the signals from the circuit.

Voltage regulation in the circuit

This is also achieved by the fact that the Zener diode comes with a fixed voltage and also operates smoothly in the reverse breakdown region. The primary purpose of voltage regulation is to prevent the output voltage from going beyond a specific limit.

If you install a Zener diode whose breakdown voltage is 20V, it means that the output voltage from the circuit will not be over 20 volts. This way, you would have achieved regulation without using many other electronic components.

Accurate signals

When the reference voltage in a circuit is maintained, one direct impact is stable output signals. This will translate to the accuracy of the electric signals from the circuit. This functionality is common in circuits that are used for signal conversion. Let’s take an example of a device used for converting analog signals to digital signals. The conversion should be executed smoothly and in a precise manner without any loss of signals. The presence of reference voltage will ensure that output signals oscillate within a particular range hence minimizing signal noise or distortion.

Choosing reference voltage for a circuit

While buying diodes for voltage reference circuits is an important step, all this starts with choosing the reference voltage for the circuit. After all, the diode that you will choose will be based on the value of the reference voltage.

The first step is to determine the output voltage that you would like to get from the circuit. This is the voltage that will be running devices and components from the circuit.

You should also consider other factors that are likely to influence the accuracy of the voltage reference. One of these factors is the operating temperature. The circuit should be able to operate effectively without its effectiveness being influenced by temperature variation. On the upper hand, the Zener diode takes care of this temperature factor.

Conclusion

I hope that with this guide, you now have a full understanding on the role of diodes in voltage reference circuits. They are responsible for the smooth running of these circuits. They also guarantee the stability and accuracy of the circuits. Using quality components that are compatible with the circuit requirements is the surest way of getting the best from the voltage reference circuits.

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