LT1950

17

sn1950 1950fs

SLOPE

BLANK

SYNC

FB

COMP

SHDN

GATE

GND

PGND

LT1950

5

6

3

9

4

2

1

15

11

16

7

12

10

8

13

210k

27k

6.8k

0.1

µF

T1

PA0581

2.2

µF

100V

X5R

36V

TO 72V

INPUT

10V

BIAS

470k

18k

232k

24.9k

47

µF

Si7450

330R

470pF

18k

1

µF

1

µF

47k

4

3

5

2

1

8.2V

22k

U2

LT1009

U3

LT1797

FMMT625

OC1

1950 F13

47

µH

0.015

Figure 13. 36V to 72V Input to 26V at 5A Nonsynchronous Forward Converter

LOAD CURRENT (A)

1

5

1950 F12

2

3

4

94

93

92

91

90

89

88

87

86

85

84

Figure 12. LT1950-Based Nonsynchronous

Forward Converter Efficiency vs Load

Current (Figure 13 Circuit)

High Efficiency, Isolated 26V 5A Output,

Nonsynchronous Forward Converter

Figure 13 illustrates a nonsynchronous forward converter

based on the LT1950 to provide a highly efficient, 26V 5A

isolated output from 48V input. The LT1950-based con-

verter using a single switch topology and utilizing the

LT1950s adaptive maximum duty cycle clamp is a simple

and highly optimized solution. Peak efficiencies of 92.8%

(Figure 12) are achievable. Transformer and inductor are

standard components. The quarter brick sized DC/DC

converter (2.3" by 1.45") delivers over 125W and is only

0.4" high. The 26V converter can be used as a “front line”

(isolating) converter in telecom systems with multiple

outputs.

APPLICATIO S I FOR ATIO