CP494
SWITCHMODE Pulse Width Modulation Control Circuit
V
ref
6
5
R
C
T
V
CC
R
Master
S
T
R
T
12
V > 40V
in
1N975A
V = 39V
C
T
Z
5.0V
Ref
V
ref
270
Gnd
7
6
5
R
C
T
Slave
(Additional
Circuits)
T
Figure 18. Slaving Two or More Control Circuits
Figure 19. Operation with Vin > 40 V Using
External Zener
+V = 8.0V to 20V
in
12
+V = 28 V
O
I = 0.2 A
1N4934
47
O
1
V
CC
T
1
+
-
8
22
k
2
Tip
32
C
C
1
L
1
1M
33k
3
+
CP494
50
35V
Comp
-
+
50
25V
0.01
0.01
15
16
11
Tip
32
4.7k
2
+
50
35V
+
1
2
OC
V
REF
DT
C
T
R
T
Gnd
7
E
E
1.0
47
1N4934
13 14
4
5
6
9
10
+
240
4.7k
4.7k
10
10k
15k
0.001
All capacitors in mF
Figure 20. Pulse Width Modulated Push–Pull Converter
Test
Conditions
= 10 V to 40 V
Results
14 mV 0.28%
3.0 mV 0.06%
65 mV pp P.A.R.D.
1.6 A
L1 - 3.5 mH @ 0.3 A
T1 - Primary: 20T C.T. #28 AWG
T1 - Secondary: 12OT C.T. #36 AWG
T1 - Core: Ferroxcube 1408P-L00-3CB
Line Regulation
Load Regulation
Output Ripple
V
in
V
in
V
in
V
in
V
in
= 28 V, I = 1.0 mA to 1.0 A
O
= 28 V, I = 1.0 A
O
Short Circuit Current
Efficiency
= 28 V, R = 0.1 W
L
= 28 V, I = 1.0 A
71%
O
* All specs and applications shown above subject to change without prior notice.
1F-5 NO.66 SEC.2 NAN-KAN RD ., LUCHU , TAOYUAN, TAIWAN
Tel:886-3-3214525
Email: server@ceramate.com.tw
Http: www.ceramate.com.tw
Rev 1.0 Apr.19,2004
Page 9 of 11
Fax:886-3-3521052
CERAMATE [ CERAMATE TECHNICAL ]
