Detailed Circuit Descriptions; Power Circuit - Fluke ScopeMeter 123 Service Manual

Mode
Idle mode No power adapter and no battery
Off mode No power adapter connected, battery
installed, test tool off
Mask active mode No valid instrument software, or ^ and > key
pressed when turning on
Charge mode Power adapter connected and test tool off
Operational & Power adapter connected and test tool on
Charge mode
Operational mode No power adapter connected, battery
installed, and test tool on

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.
CHARGER/CONVERTER
FROM POWER
ADAPTER
V506
R501
V503
R502
C502
Table 3-2. Fluke 123 Operating Modes
Conditions
VBAT
R503
VBATSUP
L501
R513
VBATHIGH
VBATT
C503
TEMP
R512
TEMPHI
IBATP
R504
R506
R507
CHAGATE
CHASENSN
CHASENSP
R514
IIMAXCHA
VCHDRIVE
R516
VADALOW
VADAPTER
Figure 3-3. Power Supply Block Diagram
Circuit Descriptions

3.3 Detailed Circuit Descriptions

Remark
no activity
P-ASIC & D-ASIC powered
(VBAT & +3V3GAR).
Mask software runs
Batteries will be charged
Test tool operational, and
batteries will be charged
Test tool operational, powered
by batteries
FLY BACK
CONVERTER
V569
60 69 66
64 VGARVAL
Vref
7
3 78 BATVOLT
5 79 BATTEMP
Amplify
4
Level shift
9 77 BATCUR
16 80 CHARCURR
CONTROL
14
15 COSC 43
100kHz
6
19
8
12
V565
20
V566
18 18 P7VCHA
linear regulator linear regulator
+12V
22
linear regulator
POWER ASIC
3
SUPPLY
+3V3GAR
C553
MAINVAL
C507
3-9