AN-32
+
+
VO
-
VAC
CIRCUIT PERFORMANCE
Circuit Tolerance ±5%
Load Regulation ±2.5%
Line Regulation ±1.5%
CIN
15 Ω
TOPSwitch-GX
1N5251D
22 V
1%
D
S
L
CONTROL
C
Feedback Circuit
X
F
100 nF
50 V
PI-3330-091102
Figure 4. Primary/Enhanced Feedback Circuit.
+
+
VO
-
VAC
∗
47 Ω
CIN
CIRCUIT PERFORMANCE
Circuit Tolerance ±5%
Load Regulation ±1%
Line Regulation ±0.5%
∗∗
470 Ω
TOPSwitch-GX
LTV817A
D
S
L
CONTROL
C
Feedback Circuit
X
F
Zener, 2%
∗
47 Ω is suitable for VO up to 7.5V. For VO > 7.5V, a higher value may be required for optimum transient response.
∗∗
470 Ω is good for Zeners with IZT = 5 mA. Lower values are needed for Zeners with higher IZT. (E.g. 150 Ω for IZT = 20 mA).
PI-3328-112202
Figure 5. Opto/Zener Feedback Circuit.
B
12/02
6
ETC [ ETC ]
