Renesas M3A-HS71, User Manual

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Functional Overview
2.9 Power Supply Circuit
Rev.1.01 2008.05.07 2-28
REJ11J0012-0101
2
2.9 Power Supply Circuit
In the SH7670 CPU board, 5V-power supply is input to the board to generate 3.3V and 1.2V by a regulator.
The regulator used is an output voltage variable type so that any voltage value can be generated by changing the
resistance.
Figure 2.9.1 shows the block diagram of SH7670 CPU board power supply circuit.
5V
VIN
VOUT
TAB
ADJ
3
2
4
1
10 F
22 F 22 F
110
180
SW2
J15
LMS1587CS-ADJ
VIN1
VIN2
ON/OFF#
PWGD
EAO
VREF
LX1
LX2
PGND2
PGND3
CRFB
PGND1
VFB
AGND
FIN
5V
DNF
68K
100K
470K
Ω
332K
47pF
4.7 F
4.7 F
2.2 H
5V TO 1.2V STEP DOWN REGULATOR
5V TO 3.3V LINEAR REGULATOR
R2A20101NP
HD74LV2G14A
RNA50C27AUS
SWG
5
2
5
23
21
22
10
11
20
15
16
17
9
8
4
25
1A 1Y
2A
2Y
3A
3Y
VCC
GND
8
1
2
3
4
7
6
5
External
power supply
3.3V
Flash
memory
SDRAM
Other logic
IC
Extension
connector
3.3V
External
power
supply
1.2V
USB SH7670
JP3
JP4
1 3 2
1
3
2
J17
AC adaptor jack
1
3
2
Figure 2.9.1 Power Supply Circuit Block Diagram