Microchip Technology DM330031, Руководство пользователя

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Design Details

2020 Microchip Technology Inc. DS50002927A-page 61
C.3 AUXILIARY POWER SUPPLY
The auxiliary power supply circuit consists of the following three stages (see
Figure C-4 ):
• +12V Output Power Supply
• +5V Output Power Supply
• +3.3V Output Power Supply
FIGURE C-4: AUXILIARY POWER SUPPLY
C.3.1 +12V Output Power Supply
The +12V output power supply is a synchronous buck converter (see Figure C-5 )
based on MIC28511. This power supply stage has the following specifications:
• Input Voltage (V
IN
) Range = +14V to +48V
• Output Voltage (labeled as ‘+12V’) = +12V
FIGURE C-5: +12V POWER SUPPLY CIRCUIT
V
IN
+12V
+12V Output
DC-DC
Converter
(MIC28511)
PGND
+5V
+5V Output
DC-DC
Converter
(MCP16301)
DGND
+3.3 VA
+3.3V Output
LDO
(MCP1826)
AGND
+3.3V
DGND
Auxiliary Power Supply
PGND
V
DD
19
PV
DD
20
PV
IN
7
PV
IN
8
PV
IN
9
V
IN
17
FREQ
24
EN
16
DL (NC)
1
DH (NC)
3
SW
12
SW
21
(EPAD3) SW
27
LX
5
PV
IN
4
PV
IN
(EPAD1)
25
BST
6
I
LIM
18
FB
14
PGOOD
15
AGND
13
PGND
2
PGND
10
PGND
11
PGND
22
PGND
23
(EPAD2) PGND
26
MIC28511
U1
0.1 μF
C2
0.1 μF
C6
100k
R3
PGND
+12V
1.21R
R2
2.2 μF
C1
2.2 μF
C3
100k
R8
100k
R7
DNP
R11
1.21R
R5
2.2 μF
C15
22 μF
C13
BAT46W
D1
10R
R1
DNP
C4
PGND
100 μH
L1
47 μF
C7
2.2 μF
C8
715R
R10
3300 pF
C5
0.1 μF
C22
PGND
1k
R4
PGND
0.1 μF
C30
10k
R6
10k
R9
V
IN