TL494
Figure 18. Slaving Two or More Control Circuits
Vref
RS
6
5
RT
CT
Vref
6
RT
5
CT
Slave
(Additional
Circuits)
RT
Master
CT
Vin > 40V
1N975A
VZ = 39V
270
5.0V
Ref
Gnd
7
VCC
12
Figure 19. Operation with Vin > 40 V Using
External Zener
Figure 20. Pulse Width Modulated Push–Pull Converter
+Vin = 8.0V to 20V
12
1
2
1M
33k
0.01 0.01
3
15
16
+
–
Comp
–
+
OC VREF DT CT RT Gnd E1 E2
13 14
4
5
6
7
9 10
+
10
10k
15k
0.001
TL494
C2
11
Tip
32
47
VCC
C1
8
47
Tip
32
+
50
25V
1N4934
240
T1
1N4934
22
k
+
50
35V
4.7k
1.0
+VO = 28 V
IO = 0.2 A
L1
+
50
35V
4.7k
4.7k
All capacitors in
µF
Test
Line Regulation
Load Regulation
Output Ripple
Short Circuit Current
Efficiency
Conditions
Vin = 10 V to 40 V
Vin = 28 V, IO = 1.0 mA to 1.0 A
Vin = 28 V, IO = 1.0 A
Vin = 28 V, RL = 0.1
Ω
Vin = 28 V, IO = 1.0 A
Results
14 mV 0.28%
3.0 mV 0.06%
65 mV pp P.A.R.D.
1.6 A
71%
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
MOTOROLA ANALOG IC DEVICE DATA
9
MOTOROLA [ MOTOROLA, INC ]
