SWITCH POWER BOARD
TABLE OF CONTENTS
Circuit Diagram ............................................................................... 6-2
PCB Layout View ............................................................................ 6-3
Parts List ......................................................................................... 6-4
6-1
6-1
TL431 EQUIVALENT SCHEMATIC
TOP249 BLOCK DIAGRAM
VOLTAGE
ANODE
REF
CATHODE
2.4 k
7.2 k
3.28 k
20 pF
4 k
1 k
800
800
800
20 pF
150
10 k
SHUTDOWN/
AUTO-RESTART
PWM
COMPARATOR
CLOCK
SAW
HALF
FREQ.
CONTROLLED
TURN-ON
GATE DRIVER
CURRENT LIMIT
COMPARATOR
INTERNAL UV
COMPARATOR
INTERNAL
SUPPLY
5.8 V
4.8 V
SOURCE (S)
S
R
Q
D MAX
STOP
SOFT-
START
-
+
CONTROL (C)
LINE-SENSE (L)
EXTERNAL
CURRENT LIMIT (X)
FREQUENCY (F)
-
+
5.8 V
1 V
IFB
R E
Z C
V C
+
-
LEADING
EDGE
BLANKING
÷
8
1
HYSTERETIC
THERMAL
SHUTDOWN
SHUNT REGULATOR/
ERROR AMPLIFIER
+
-
DRAIN (D)
ON/OFF
SOFT
START
DC
MAX
V BG
DC
MAX
V BG + V T
0
OV/UV
VI (LIMIT)
CURRENT
LIMIT
ADJUST
LINE
SENSE
SOFT START
LIGHT LOAD
FREQUENCY
REDUCTION
STOP LOGIC
OSCILLATOR WITH JITTER
PIN NO
1
2
3
4
5
6
Voltage 2.98
0
-0.6
0
2.6
154
PIN NO
1
2
3
Voltage 2.48
0
5.1
PIN NO
1
2
3
4
Voltage 27.7 26.6 2.5 16.7
IC903 (TOP249)
SN901 (SFH615-3)
IC904 (TL431)
Q903 (PN2222A)
PIN NO
b
c
e
Voltage 0
31.5
0
PIN NO
b
c
e
Voltage -14.1-4.49 -14.1
Q912 (2N7000)
Q910 (2N7000)
PIN NO
b
c
e
Voltage -14.1-4.49 -14.1
Q904 (TIP120)
PIN NO
b
c
e
Voltage 6.68 31.5 7.2
PIN NO b
c
e
Voltage 0.7 0.06
0
Q913 (2N7000)
Содержание MRD300/37
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