2015 Microchip Technology Inc. DS20005399A-page 5
LR8
FIGURE 3-3: SMPS Start-Up Circuit
FIGURE 3-4: High-Voltage, Adjustable, Constant-Current Source
+
V
OUT
1
-
V
CC
V
AUXILIARY
V
IN
= (V
OUT
+ 12V) to 450V
FB
PWM IC
+
V
OUT
1
-
LR8
VOUT
ADJ
VIN
LR8
V
IN
=
(V
OUT
+ 12V) to 450V
R
Load
I
OUT
=
1.20V
R
+
-
1.0μF
VOUT
ADJ
VIN
