Functional Block Diagram Of Large Scale Integrated Circuit - Keithley 616 Instruction Manual

THEORY OF OPERATION
4-4. AUTO-RANGING CIRCUIT.
This circuit is located
2577BE) .
(QA40B) with exception of decoding diodes 030lA
through 0301H and FET switches Q302 through Q305.
(TH)
The threshold input
signals are used to determine the proper range.
Ranging i8 b i directional so that upranging or
downranging to an adjacent range occurs .
ranging feature is defeated by grounding pin 6
on LSI QA408 .
DISPLAY DRIVE .
4-5.
four LED, 7-segment readouts plus a polarity /over­
range readou t . The display drive circuit i s multi­
plexed 80 that only eight lines are driven at a time.
a .
The disp lay is controlled b y the
in the LSI QA20 8 .
four multiplexing lines which turn on the anodes of
each seven segment readout .
used for each of the four digits.
point, and dummy zero (on the . 0 1000V range) are not
QA40lA through QA40lD are used
multiplexed,
to provide sufficient drive for trans istors Q40S
through Q407 respectively.
readout is pulled up to approx. +10 volts to light
a particular digit.
b .
cathode connections for each segment as given in Table
4-5.
CS
A-D
CONV.
CLOCK
TIMING
CKTS.
MULTIPLEX
OUTPUT
FIGURE 3 0 .
26
(Refer to schematic
on the LSI mod u le
and current switch (CS)
The auto­
The 616 disp lay is composed of
This circuit is contained
Four of the lines are
Polarity, decimal
Each anode of each LED,
Each display module has separate
BC D
COUNTERS
LATCHES
MULTIPLEXER
7 SEGMENT
DECODER
Functional Block Diagram o f Large Scale Integrated Circuit .
NOT MULTIPLEXED
I
- -
I
,
(MR)
Numeral
0
1
2
3
4
5
6
7
8
9
decimal
LSI CHIP
AUTO
OUTRANGE
DISPLAY
OUTPUTS
TO READOUTS
" 'I " "
,--, ,--- -- -, ,--- -- -, ,--- -- -,
- - - -
• • •
• • •
• • •
- -
• •
I I I • • •
I
- - .. . -
, ,
,
FIGURE 3 1 . Digital Display,
TABLE 4-5.
Display Coding
A, B , C , D , E , F
B , C ,
A , B , D , E , G
A , B , C , D , G
B , C , F , G
A , C , D , F , G
A , C , D , E , F , G
A , B , e
A , B , C , D , E , F , G
A , B , e , E , F , G
decimal
FUNCTION
INPUTS
FUNCTION
DECODER
RANGE
COUNTER
FUNCTION
DECIMAL
POINT
MODEL 616
.
-
•
..
•
-
,
Pins
1 , 13 , 10 , 8 , 7 , 2
13 , 10
1 , 13 , 8 , 7 , 11
1 , 13 , 10 , 8 , 11
13 , 10 , 2 , 11
1 , 10 , 8 , 2 , 11
1 , 10 , 8 , 7 , 2 , 1 1
1 , 13 , 10
1 , 13 , 10 , 8 , 7 , 2 , 11
1 , 13 , 10 , 7 , 2 , 11
6
R ANGE
OUTPUTS
1175