Low profile transformer

1. A low-profile transformer, comprising:

a core unit having a pair of opposingly arranged base portions, an inserting portion, and a pair of opposingly arranged lateral portions,

wherein the inserting portion has a long axis, the inserting portion and the lateral portion extend from the base portion substantially along the long axis,

wherein the top-facing edge of the lateral portions is chamfered,

wherein the lateral portion is spaced from the inserting portion, defining a pair of coil winding space there-between for passing coils; and

at least a primary coil and a secondary coil wound around the inserting portion,

wherein the primary coil has a primary coil winding number (N p ) while the secondary coil has a secondary coil winding number (N s ), the ratio of N p and N s defines a coil winding ratio (N),

wherein the N p and N selectively satisfy the solution space of a characteristic effective area function A e (N p , N) and a characteristic magnetic flux variation function ΔB(N p , N), which are provided by applying predetermined operational and material specifications to a characteristic equation:

A

e

=

V

in_min

⁢

D

⁡

(

V

in_min

,

N

,

V

o

)

N

p

⁢

Δ

⁢

⁢

B

·

fre

wherein

A e denotes an effective cross-sectional area of an inserting portion,

V in — min denotes minimum AC (alternating current) input voltage in [V],

N denotes winding ratio between primary and secondary windings,

V o denotes DC output voltage in [V],

D (V in — min , N, V o ) denotes duty cycle, wherein

D

1

-

D

=

N

⁢

V

0

V

in_min

,

Np denotes primary winding number,

ΔB denotes change in magnetic flux density in [Tesla],

fre denotes operating frequency in [KHz].

2. The transformer of claim 1 , wherein the core unit comprises a pair of core members, each of which includes one of the base portions, an inserting sub-portion correspondingly constituting the inserting portion upon assembly of the core members, and a pair of lateral sub-portions correspondingly constituting the lateral portions upon assembly of the core members;

the transformer further including a frame unit comprising a generally hollow structure having two opposite ends, the hollow structure defining a core receiving channel for conformally receiving the inserting portion,

wherein the frame unit further comprises a pair of flanges arranged at the opposite ends of the frame unit defining a winding portion there-between, the coils being wound on the winding portion of the frame unit;

wherein the base portion of the core member abuts the flange upon insertion into the frame unit;

wherein the transverse cross-section of the inserting portion of the core unit is substantially elliptical;

wherein the transverse cross-section of the winding portion of the frame unit is substantially elliptical;

wherein the upper portion of the flange is chamfered.

3. The transformer of claim 2 ,

wherein the frame unit includes two connector portions extending respectively and asymmetrically from the bottom surface of the opposite ends thereof along the long axis;

wherein each connector portion has a plurality of conducting pins disposed there on;

wherein one of the connector portion extends further away from the frame unit than the other.

4. The transformer of claim 1 , wherein the height of the top surface of the inserting portion is arranged horizontally lower than that of the lateral portion.

5. The transformer of claim 1 ,

wherein a coil winding width (W) of the transformer is defined between the inserting portion and each of the lateral portions,

wherein a coil winding length (L) of the transformer is obtained by dividing a total required coil winding area (A total ) by the coil winding width (W),

wherein the total required coil winding area (A total ) is calculated from the N p and Ns.