The Role of Diodes in Battery Charging Circuits

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Battery charging has become an essential aspect of digital electronics. We have many portable electronic devices that can store power and be used from any location without being plugged into a power source. They are usually recharged in case their energy runs low. The charging process is made possible by the battery charging circuits. The chemical composition of these batteries allows them to be recharged so that they can have full energy as before. Lead acid batteries and even modern lithium-ion or nickel metal hydride batteries are just common examples of such batteries.

Are you building an electronic product or device that will have a rechargeable battery? You will have to incorporate a battery charging circuit into such a device. Such circuits have different electronic components: both passive and active components. One of the must-have components in this circuit is a diode.

Diodes play very important roles in the charging circuits. In this article, we are going to discuss the important roles of diodes in battery charging circuits. We will also look at the specific types of diodes used in the circuits and the factors that make diodes perfect for battery charging.

How do I identify a failing diode in a charging circuit?

We have seen the relevance of diodes in battery charging circuits. The fact that different applications have different charging systems makes it harder to narrow down the exact problem in the circuit. Some applications have more diodes than others.

One notable sign of a failed charging system is a poorly charged battery. Let’s say you leave your battery to charge but several hours later, you find out it has not even attained half charge. This could mean that some AC current leaked during the charging process hence the slow charging rate.

Poor charging is also indicated by an ultra-fast charging rate. The diode may be physically damaged hence allowing direct current into the battery. This is quite a common problem that is associated with a shorted diode.

In other cases, the battery may be discharged instead of charging. A diode can be a culprit whereby it facilitates the draining process in the circuit. The backward movement of current could be caused by a damaged diode.

In overall, it can be quite difficult to detect a failing diode in the charging circuit. In most scenarios, we tend to blame the battery or a problem in the power source yet the issue could be with the charging system.

To be on the safe side, it will be prudent to test the diodes so that you can find out the exact problem. If the diode is working perfectly, then you can proceed to test other elements of the battery charging circuit. You will have to do relevant replacements in case some components are damaged.

Overview of the charging circuits

To understand the role of transistors in charging circuits, it will be vital to know some basic elements and components of these circuits.

As we have already defined, a charging circuit is all about replenishing the battery energy. It gets the power from an external power outlet and transmits it straight to a rechargeable battery.

The circuit is important as it regulates the whole charging process by ensuring that the battery gets the right proportions of charges over a defined period.

Also, charging circuits are on different components of the charging system. You will find them at the power source, on the controller, main charging unit, and on the battery interface. It all depends on the nature of the battery and the application area.

Diodes as rectifiers in charging circuits

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This is the first and primary role of diodes in battery charging circuits. We can define rectification as the conversion of power from the alternating current (AC) to the direct current (DC). Diode is the simplest type of rectifier as it can be used for both half-wave and full-wave rectifiers.

In most electronic applications, chargers are connected directly to the AC power socket on the wall socket. It will have to be converted into DC current before being channeled to the battery to initiate the discharging process. The rectification process is enabled by the p-n junctions of the diodes.

Diodes protect the battery

Diodes in the charging circuits protect batteries from various risks.  There are various ways in which they achieve this role. First, the fact that they are used as rectifiers means that they ensure the battery gets the correct type of electric current when charging.

Another way in which diodes play a protective role in the charging circuits is through voltage regulation. This function is mainly performed by the Zener diode which will always have a reference breakdown voltage and is designed to work in the reverse bias mode. The diode will conduct as any other diode but will be reverse-biased when the maximum current in the circuit is attained.

Control the direction of charging

In the charging circuit, electric current is designed to flow from the power source to the battery. This is a primary feature and function of diodes. They ensure that current flows in one direction and not the opposite way. By determining the direction of the current, diodes prevent the discharge of current from the battery.

Conclusion

Battery charging is a simple element of the power electronics yet it plays an important role in making our lives convenient. Whether it is small electronic devices such as smartphones or in the automotive industry, it is difficult to underestimate the power of the charging technology, which is basically powered by charging circuits.

Whether it is a NiMH, NiCd, Li, or PbA batteries, the best charging circuits will guarantee ultimate performance from the batteries. Keep in mind that a good charging system has a role to play in determining the reliability and durability of the battery.

Also, it is clear that there are specialized diodes that are used in the charging circuits. So, before you buy diodes for charging circuits, ensure that they are designed for your specific application area.

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