Improve Power Inductors: 5 Key Performance Tips
Power inductors are passive electronic components that store energy by creating magnetic fields with tightly wound coils of conductive wire.
Characteristics
Power inductors are an indispensable component in DC-DC converters and other power supply circuits, serving to store energy and filter EMI noise while offering lower signal loss capability and greater power handling capabilities than competing components.
To ensure proper functioning of these devices, designers must pay special attention to their voltage resistance and current ripple characteristics.
The characteristics of power inductors vary depending on the size and frequency of the load. Copper and iron losses are two common forms of loss that cause temperature increases; to minimize them, select an inductor with low core loss at high frequencies.
The DC resistance (Rdc) of power inductors is often the key factor governing their efficiency, so it is possible to reduce this value by using thinner wire or a larger cross-sectional area, but it will significantly decrease the inductance.
Designers must ensure a large reduction in inductance by selecting an appropriate peak current rating for the device. This value acts as a safeguard, protecting against overheating damage while reflecting the maximum current flow through it.
Power inductors use their current rating to indicate the maximum current that can be transmitted without reaching magnetic saturation, determined by the maximum allowable currents DC superposition characteristics and the maximum allowable temperature rise limits. These power inductors generate their magnetic field through the rotation of domains within their core materials. As the magnetic field changes, these domains must change direction – creating what is known as core loss.
Inductors come in shielded and unshielded versions.
Shielded power inductors are commonly used in applications that require high inductance at high frequencies; Unshielded inductors can be found more commonly at lower frequencies with more stable currents.
Shielded and unshielded versions differ in terms of DCR (DC resistance) values ​​and temperature coefficients.
Forms
Power inductors have two main purposes in an electronic circuit: they store energy in magnetic fields during active periods and deliver it to loads during off-peak periods, via Lenz’s Law.
Current flows through inductors when current is applied to their terminals, with its direction determined by the changing magnetic fields within its core. When this change in field direction is stopped or reversed, inductors generate a voltage at their terminals when current flows, and the direction is determined by these changes in the magnetic fields.
If this change in field displacement is interrupted or reversed, this current will quickly increase in speed, producing a high voltage at its terminals, sufficient to cause sparks that can endanger both the circuit and the user.
Inductors come in various sizes and shapes to suit specific applications.
They are available in wirewound and multilayer designs with ferrite or metal core materials for optimal design. The choice of main material also affects its performance; low permeability results in lower inductance values, while higher permeabilities support greater inductance at higher frequencies.
Power inductors are ubiquitous in electronic devices, from cell phones and laptops to automotive DC-DC converters.
When selecting a power inductor, it is essential to look at its inductance value, DC overlap characteristic, temperature characteristic and leakage flux properties.
Ideal power inductors should not saturate during peak application current and be designed to handle this high current without overheating or short circuiting. You can click on the link: https://en.wiktionary.org/wiki/short_circuit to know more about short circuit.
Specifications typically provide current limits for reaching magnetic saturation as well as temperature rise limits; Using an inductor with gradual magnetic saturation characteristics will help avoid sudden drops in inductance.
Copper loss, or the amount of energy lost through magnetic losses in its core and windings, must also be taken into consideration when selecting a power inductor for any application.
Materials
Power inductors have long been used in electronic devices to convert DC input voltage to DC output current. Its purpose is to maintain inductance during the passage of current, with low resistance characteristics; therefore, they require durable materials capable of handling sufficient current while also having energy storage properties.
A power inductor consists of a coil of conductive material, typically insulated copper wire, wound around an air-core inductor made of plastic (called an air-core inductor) or an iron core made of metal alloy ferromagnetic (known as ferrite or iron core power inductor).
The magnetic field created by its magnetic core increases inductance – defined as the product of magnetic permeability and winding ratio. You can click here to find out more.
The core is designed to prevent eddy currents to limit power losses in an inductor, similar to how transformers work. This is done through laminations of electrical steel sheets arranged parallel to the magnetic field and with an insulating coating applied to their surfaces.
Soft ferrite is often preferred for cores above audio frequencies as it does not cause as large a power drain as common iron alloys at these higher frequencies.
Small power inductors come in the form of molded cases designed to imitate resistors, easily identifiable with an ohmmeter. These inductors generally feature a single or ferrite core and are ideal for applications that require small sizes with low resistance values.
Primary material choices play a key role in choosing an inductor for any application, which should be taken into consideration when choosing one. Ferrite and ceramic cores are common choices.
Project
Power inductors play a fundamental role in circuit design. They store energy efficiently while ensuring low core losses for efficient energy conversion. Unfortunately, designing an inductor can be a complex task that must consider many variables.
First, when selecting a power inductor, it is important to pay close attention to its DC resistance. A power inductor with high DC resistance will result in excessive current flow and heat production, which may eventually cause premature device failure. When specifying one, make sure its DC resistance falls below the maximum operating frequency.
Finally, when choosing a power inductor for your project, it is essential to observe its size and dimensions. This will ensure it fits properly onto your device, taking into account any associated terminals such as cables, towers, and terminals.
