INNOLINE
DC/DC-Converter
Output Current vs Input Voltage
R-7xxxP_D
Series
How to calculate the max output current
The internal power dissipation(P
D
)follows the equation:
P
D
= Io × Vo × (1-η)
Io = P
D
/ Vo × (1-η)
Where
P
D
= Internal power dissipation
Io = Output current
Vo = Output voltage
η
= Efficiency
Example: R-745.0P , at Vin = 28Vdc , Vo = 5Vdc ,η=91% (see "Selection Guide" table)
(a) When Ta = 60°C , P
D
= 1.4 Watt (see beside diagram)
Io = 1.4(W) / 5(V) × (1-0.91) = 3.11(A)
(b) When Ta = 85°C , P
D
= 1 Watt (see beside diagram)
Io = 1(W) / 5(V) × (1-0.91) = 2.222(A)
(c)
At Vin = 12Vdc efficiency = 94% (see "Selection Guide" table)
When Ta = 85°C , P
D
= 1 Watt (see beside diagram)
Io = 1(W) / 5(V) × (1-0.94) =3.33(A)
Ambient Temperature (°C)
90
85
80
60
40
20
0
0.5
1
1.4
Internal Power Dissipation (W)
Characteristics
R-72xx / R-73xx
Ripple VS Vin
50
Vo=15V
Vo=12V
Vo=6.5V
Vo=9V
Vo=5V
R-74xx
Ripple VS Vin
100
6.5V
50
Ripple (mV)
5V
3.3V
( Vo )
5
10
Vin ( V )
Ripple Vs Vin
15
20
25
28
R-72xx / R-73xx
Efficiency VS Vin
100
15V
6.5V
5V
3.3V
25
50
Efficiency (%)
Ripple (mV)
Vo=3.3V
( Vo )
5
10
Vin ( V )
15
20
25
28
( Vo )
5
10
Vin ( V )
Efficiency Vs Vin
15
20
25
28
Ripple Vs
Vin
R-74xx
Efficiency VS Vin
100
Vo=6.5V
Vo=5V
Vo=3.3V
R-72xx / R-73xx / R-74xx
Efficiency / Load Vin=Min
100
6.5V
5.0V
3.3V
R-72xx / R-73xx / R-74xx
Efficiency / Load Vin=Max
100
90
80
15V
5.0V
3.3V
90
50
Efficiency (%)
Efficiency (%)
Efficiency (%)
80
( Vo )
70
1
3
2
Efficiency Vs Iout (Vin=Min)
4
60
( Vo )
1
3
2
Efficiency Vs Iout (Vin=Max)
4
( Vo )
5
10
Vin ( V )
Efficiency Vs Vin
15
20
25
28
www.recom-international.com
27-March-2007
167
RECOM [ RECOM INTERNATIONAL POWER ]
