User's Manual

Circuit Descriptions
3.3 Detailed Circuit Descriptions
3
3-9
Table 3-2. Fluke 123 Operating Modes
Mode Conditions Remark
Idle mode No power adapter and no battery no activity
Off mode No power adapter connected, battery
installed, test tool off
P-ASIC & D-ASIC powered
(VBAT & +3V3GAR).
Mask active mode No valid instrument software, or ^ and > key
pressed when turning on
Mask software runs
Charge mode Power adapter connected and test tool off Batteries will be charged
Operational &
Charge mode
Power adapter connected and test tool on Test tool operational, and
batteries will be charged
Operational mode No power adapter connected, battery
installed, and test tool on
Test tool operational, powered
by batteries
3.3 Detailed Circuit Descriptions
3.3.1 Power Circuit
The description below refers to circuit diagram Figure 9-5.
Power Sources , Operating Modes
Figure 3-3 shows a simplified diagram of the power supply and battery charger circuit.
V566
R516
R514
R502
R512
R513
P7VCHA
22
60
BATCU
R
FROM POWER
ADAPTER
CHAGAT
E
CHASENSN
V506
V503
L501
C503
VBAT
CONTROL
100kHz
POWER ASIC
TEM
P
TEMPHI
IBAT
P
CHASENS
P
IIMAXCHA
VCHDRI V
E
VADALOW
C502
VADAPTE
R
BATVOLT
BATTEM
P
CHARCUR
R
Amplify
Level shift
R504
R501
Vref
+3V3GAR
VGARVA
L
FLY BACK
CONVERTER
MAI NVAL
VBAT
T
R503
VBATSU
P
3
5
4
9
16
14
15
6
19
8
20
1
2
80
7
7
79
78
64
69 66
linear regulator
VBATHIGH
7
C553
43
C507
18
COS
C
V569
R506
R507
V565
CHARGER/CONVERTER
SUPPLY
linear regulator
linear regulator
+12V
18
Figure 3-3. Power Supply Block Diagram