pq1cf2 ETC-unknow, pq1cf2 Datasheet - Page 10

• Manufacturer Part Number: pq1cf2
• Description: To-220 Type Chopper Regulator
• Manufacturer: ETC-unknow

Oblique line portion : Overheat protection may operate in this area.
Chopper Regulators
Fig. 8 Power Dissipation vs. Ambient
Area of heat sink is obtained as follows,
(A)Increasing junction temperature difference from ambient temperature( T
(B)Thermal resistance R
(C)Thermal resistance of heat sink R
(D)Area of heat sink is obtained from thermal resistance R
20
15
10
Precations in designing heat sink
5
0
–20
Thermal resistance R
Thermal resistance R
characteristics.
It is recommended that T
Temperature
T
j
=T
Ambient temperature T
j
–Ta
0
P
P
D2
D1
P
P
20
D1
D2
On condition that R
:No heat sink
:With infinite heat sink
40
th(j-a)
th(j-a)
th(c-a)
= T
is obtained from
<=R
60
j
=70 to 80% of T
a
th(j-a)
j
( ˚C )
/P ˚C/W
80
th(c-a)
th(j-c)
–R
th(j-c)
100
is obtained from R
of PQ1CF2=6.67˚C/W
j
MAX.
˚C/W
T
j
and internal dissipation loss (P)obtained from equation q
th(c-a)
th(j-a)
Fig. 9 Thermal Resistance vs. Area of Heat
with thermal resistance-heat sink area
PQ1CF2
100
10
1
10
sink
2mm thickness aluminum plate
j
Area of heat sink S(cm
)is obtained as follows.
Regulator
View of regulator attached
on the center of square
heat sink.
heat sink
1000
2
)
PQ1CF2
1000