What are the five characteristic parameters of inductor | GETWELL

The coil wound into a spiral shape is inductive, and the coil used for electrical purposes is called inductors. Inductors are widely used in electronic circuits, and can be divided into two categories, one is inductors for signal systems, and the other is power inductors for power systems.

Inductor is widely used as a component, and some of its basic parameters are easily ignored, resulting in insufficient design and serious use problems of the product.

Taking the power inductor as an example, the basic parameters of the inductor are introduced.

inductance value

The basic parameter of inductance is also an important parameter that affects ripple current and load response.

The current of the power inductor in the converter is the triangle wave current. In general, the ripple current can be set to about 30% of the load current. Therefore, as long as the conditions of the converter are determined, the appropriate inductance of the power inductor can be roughly calculated. Selected according to the manufacturer's reference value, if you want to replace a new inductor model, its parameters should not be too different from the reference value recommended by the supplier.

saturation current

The saturation current characteristic is also called DC superposition characteristic, which affects the effective inductance when the inductor works. If the inductor is not selected properly, the inductor is easy to be saturated, causing the actual inductance value to decrease, can not meet the design requirements, and may even burn out the circuit. The definition of saturated circuit varies slightly, generally speaking, it refers to the current when the initial inductance is reduced by 30%.

temperature rise current

This is a parameter that specifies the allowable range of ambient temperature when using inductors. The definition of temperature rise current varies from manufacturer to manufacturer, generally speaking, it refers to the circuit when the temperature of the inductor is raised by 30 ℃. The effect of temperature varies with the working environment of the circuit, so it should be selected after considering the actual use environment.

DC impedance

Represents the resistance value when passing through direct current. The biggest and most direct influence of this parameter is the heating loss, so the smaller the DC impedance, the less the loss. There is a slight conflict between the reduction of Rdc and miniaturization. As long as from the above-mentioned inductors that meet the necessary characteristics such as inductance and rated current, a product with a smaller Rdc can be selected.

Impedance frequency characteristic

The impedance of the ideal inductor increases with the increase of frequency. However, due to the existence of parasitic capacitance and parasitic resistance, the actual inductor is inductive at a certain frequency, capacitive beyond a certain frequency, and the impedance decreases with the increase of frequency. This frequency is the turning frequency.

The above is the introduction of the five characteristic parameters of the inductor. if you want to know more about the inductor, please feel free to contact us.