LT1105 LINER [Linear Technology], LT1105 Datasheet - Page 22

• Manufacturer Part Number: LT1105
• Description: Offline Switching Regulator
• Manufacturer: LINER [Linear Technology]

APPLICATIONS
LT1103/LT1105
22
Flyback Waveform for Continuous Mode Operation
e
a
c
f
b
d
t = (I
U
PRI
I
)[L(lk
I
INFORMATION
U
PRI
)]/V
SNUB
SECONDARY WINDING VOLTAGE
[V
BIAS WINDING VOLTAGE
[V
0V
SECONDARY CURRENT
V
PRIMARY SWITCH VOLTAGE
[V
V
AREA “a” = AREA “b” TO MAINTAIN
ZERO VOLTS ACROSS PRIMARY
0V
0V
AREA “c” = AREA “d” TO MAINTAIN
ZERO VOLTS ACROSS SECONDARY
N • V
AREA “e” = AREA “f” TO MAINTAIN
ZERO VOLTS ACROSS BIAS WINDING
N2 • V
I
0A
I
SWITCH CURRENT
0A
I
SNUBBER DIODE CURRENT
0A
PRIMARY CURRENT
0A
I
SEC =
PRI
PRI
W
PRI
ZENER
IN
OUT
OUT
OUT
IN
+ Vf + (I
IN
+ Vf + (I
+ Vf + (I
I
PRI
/N
SEC
SEC
SEC
• R
• R
• R
U
P
P
P
)]/N1
)]
)]/N
a
e
c
Flyback Waveform for Discontinuous Mode Operation
b
d
f
t = (I
PRI
)[L(lk
I
I
PRI
)]/ V
SNUB
SECONDARY WINDING VOLTAGE
[V
AREA “c” = AREA “d” TO MAINTAIN
ZERO VOLTS ACROSS SECONDARY
N • V
[V
PRIMARY CURRENT
I
SWITCH CURRENT
I
SNUBBER DIODE CURRENT
0A
AREA “a” = AREA “b” TO MAINTAIN
ZERO VOLTS ACROSS PRIMARY
AREA “e” = AREA “f” TO MAINTAIN
ZERO VOLTS ACROSS BIAS WINDING
0A
SECONDARY CURRENT
0A
0A
V
PRIMARY SWITCH VOLTAGE
[V
BIAS WINDING VOLTAGE
I
I
0V
N2 • V
PRI
0V
0V
PRI
V
PRI
SEC =
ZENER
OUT
OUT
IN
OUT
IN
+ Vf + (I
+ Vf + (I
I
+ Vf + (I
IN
PRI
/N
SEC
SEC
SEC
LT1103 WF01
• R
• R
• R
P
P
P
)]
)]/ N1
)]/ N