uc3844bvnguc3845bd ON Semiconductor, uc3844bvnguc3845bd Datasheet - Page 12

• Manufacturer Part Number: uc3844bvnguc3845bd
• Description: Current Mode Controller
• Manufacturer: ON Semiconductor

Error Amp compensation circuit for stabilizing any current mode topology except
for boost and flyback converters operating with continuous inductor current.
From V
R
R
d
i
R
f
O
C
≥ 8.8k
f
R
1(1)
2(3)
f
2.5V
+
-
EA
5.0V Ref
UC3844B, UC3845B, UC2844B, UC2845B
+
The MCR101 SCR must be selected for a holding of < 0.5 mA @ T
simple two transistor circuit can be used in place of the SCR as shown. All
resistors are 10 k.
MCR
Comp/Latch
1.0mA
101
S
R
T
Q
Figure 29. Error Amplifier Compensation
2R
R
Figure 27. Isolated MOSFET Drive
+
-
Figure 28. Latched Shutdown
3905
5(9)
2N
7(12)
V
CC
http://onsemi.com
7(11)
6(10)
5(8)
3(5)
3903
8(14)
2N
4(7)
2(3)
1(1)
C
Boundary
Isolation
R
R
12
S
EA
R
R
N
S
Q1
+
Osc
1.0 mA
Bias
V
N
in
+
0
-
P
Error Amp compensation circuit for stabilizing current mode boost
and flyback topologies operating with continuous inductor current.
C
From V
R
p
2R
I
pk
p
R
50% DC
=
V
O
GS
R
5(9)
i
V
Waveforms
R
(Pin 1)
d
A(min)
3 R
+
0
-
C
f
- 1.4
S
. The
25% DC
R
1(1)
2(3)
f
N S
N p
2.5V
EA
+
1.0mA
2R
R
5(9)