INNOLINE
R-7xxxP_D
Series
DC/DC-Converter
Output Current vs Input Voltage
How to calculating the max output current
The internal power dissipation(PD)follows the equation:
PD = Io × Vo × (1-η)
90
85
Io = PD / Vo × (1-η)
80
60
40
20
Where
PD = Internal power dissipation
Io = Output current
Vo = Output voltage
η = Efficiency
Example: R-745.0P , at Vin = 28Vdc , Vo = 5Vdc ,η=91% (see table 1)
(a) When Ta = 60°C , PD = 1.4 Watt (see fig-1)
Io = 1.4(W) / 5(V) × (1-0.91) = 3.11(A)
0
0.5
1
1.4
Internal Power Dissipation (W)
(b) When Ta = 85°C , PD = 1 Watt (see fig-1)
Io = 1(W) / 5(V) × (1-0.91) = 2.222(A)
(c) At Vin = 12Vdc efficiency = 94% (see table 1)
When Ta = 85°C , PD = 1 Watt (see fig-1)
Io = 1(W) / 5(V) × (1-0.94) =3.33(A)
Characteristics
R-72xx / R-73xx
Efficiency VS Vin
R-72xx / R-73xx
Ripple VS Vin
R-74xx
Ripple VS Vin
15V
6.5V
5V
100
50
100
3.3V
Vo=15V
Vo=12V
Vo=6.5V
Vo=9V
6.5V
5V
Vo=5V
50
25
50
Vo=3.3V
3.3V
( Vo )
( Vo )
( Vo )
5
10
Vin ( V )
15
20
25
28
5
10
Vin ( V )
Ripple Vs Vin
15
20
25
28
5
10
Vin ( V )
Ripple Vs Vin
15
20
25
28
Efficiency Vs Vin
R-74xx
Efficiency VS Vin
R-72xx / R-73xx / R-74xx
Efficiency / Load Vin=Min
R-72xx / R-73xx / R-74xx
Efficiency / Load Vin=Max
100
100
100
90
Vo=6.5V
Vo=5V
15V
5.0V
3.3V
6.5V
5.0V
3.3V
Vo=3.3V
90
80
50
80
60
( Vo )
( Vo )
( Vo )
70
5
10
Vin ( V )
Efficiency Vs Vin
15
20
25
28
1
3
4
1
3
4
2
2
Efficiency Vs Iout (Vin=Min)
Efficiency Vs Iout (Vin=Max)
www.recom-international.com
24-August-2005
3
RECOM [ RECOM INTERNATIONAL POWER ]
