Power inductor

1. A power inductor comprising:

a body comprising magnetic powder and a polymer;

at least one base provided in the body and having at least one surface on which at least one coil pattern is disposed; and

an insulation layer disposed on the base and between the coil pattern and the body,

wherein the magnetic powder comprises at least three magnetic powders having different mean values of particle sizes or different middle values of grain-size distribution from one another,

wherein a through-hole extends through a central region of the base, and wherein the coil pattern does not overlap the through-hole,

wherein the body comprises a first thickness region contacting the insulation layer and includes a magnetic powder of the at least three magnetic powders having a smallest of the mean values of the particle sizes or a smallest of the middle values of the grain-size distribution,

wherein the magnetic powder of the at least three magnetic powders having the smallest of the mean values of the particle sizes or the smallest of the middle values of the grain-size distribution contacts the insulation layer and is distributed in a peripheral region of the through-hole, and

wherein a magnetic powder of the at least three magnetic powders having a mean value of particle sizes greater than that of the smallest of the mean values of the particle sizes or a middle value of grain-size distribution greater than that of the smallest of the middle values of the grain-size distribution is distributed in a central region of the through-hole that is outside the peripheral region of the through-hole.

2. The power inductor of claim 1 , wherein the at least three magnetic powders comprise:

a first magnetic powder,

a second magnetic powder having a mean value of particle sizes or a middle value of grain-size distribution less than that of the first magnetic powder, and

a third magnetic powder having a mean value of particle sizes or a middle value of grain-size distribution less than that of the second magnetic powder,

and wherein the third magnetic powder is the smallest magnetic powder of the at least three magnetic powders.

3. The power inductor of claim 2 , wherein the body comprises a second thickness region which is defined inward from at least one of top and bottom surfaces of the base in a vertical direction and comprises the third magnetic powder.

4. The power inductor of claim 3 , wherein the body has a remaining region comprising the first to third magnetic powders.

5. The power inductor of claim 2 , wherein at least one of the first to third magnetic powders further comprises at least one magnetic powder having a different middle value of the grain-size distribution.

6. The power inductor of claim 2 , wherein the at least three magnetic powders further comprise a fourth magnetic powder having a composition different from that of each of the first to third magnetic powders.

7. The power inductor of claim 6 , wherein at least one of the first to fourth magnetic powders is crystalline.

8. The power inductor of claim 3 , wherein in the body, the second thickness region has a polymer content greater than that of the first thickness region.

9. The power inductor of claim 1 , further comprising a capping insulation layer disposed on at least one surface of the body.

10. The power inductor of claim 1 ,

wherein the body has a plurality of surfaces, wherein at least one first surface of the plurality of surfaces has a specific resistance different from that of a second surface of the plurality of surfaces.

11. The power inductor of claim 10 , wherein a surface of a side of the body, which is mounted on a printed circuit board, has specific resistance that is greater than that of the second surface.