( 4 )

Thermal Design

The heat radiation balance model of the TO-220 with the heat sink is shown as follows.

Heat radiation balance

(℃ )

(4-1)

(W)

(4-2)

Substituting "Eq.(4-2) into "Eq.(4-1)" obtains

(℃)

(4-3)

In Eq.(4-3)

Eq.(4-3) becomes Eq.(4-4).

Tj = 125℃ (max.)

(℃)

(4-4)

It means;

For more detail, please refer the heat resistance value mentioned in the specification of the heat sink

supplier.

Insert the mica paper (0.1t) and thermal conduction silicon grease between

the IC and heat sink and tighten them with the bolt by 4Kg*cm-min.

Lower Vin and / or Iout are required to linit the temperature rise.

the result of Eq.(4-4).

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