IR Camera Power
-------------------
Initial Rev. 14-SEPT-1996
Latest Rev. 11-JAN-1998
The first two section in this file are early engineering ESTIMATES of
the power dissipation. Some of this information does NOT fit the final
design. These sections have been retained because they do include some
useful information.
See the section near the end of this file for actual measured power
consumption of the camera.
A_Card Parts:
100324 -4.5V current 45 mA Typ. 70 mA Max.
-2.0V current 114 mA Typ. 114 mA Max.
+5.0V current 25 mA Typ. 38 mA Max.
TCM2620 40 mW at 300 frames per second from 5V --> 8 mA
Count half of this as analog and half as digital.
4 mA Typ.
ADS-946 -5.0V current 120 mA Typ. 160 mA Max.
+5.0V current 220 mA Typ. 270 mA Max.
AD9631 -5.0V current 17 mA Typ. 21 mA Max.
+6.0V current 17 mA Typ. 21 mA Max.
Precision -5.0V current 5 mA Typ. 8 mA Max.
Rail-Rail +6.0V current 5 mA Typ. 8 mA Max.
OpAmp
74HCT541 +5.0V current 10 mA Typ. 15 mA Max.
LM3x7 Standing Current 10 mA Typ.
An A_Card Consists of:
100324 x4 ---> 736 mA Total Typ.
TCM2620 x1 ---> 4 mA Total Typ.
ADS-946 x1 ---> 340 mA Total Typ.
AD9631 x1 ---> 17 mA Total Typ.
Precs Rail-Rail OpAmp x2 ---> 5 mA Total Typ.
74HCT541 x2 ---> 20 mA Total Typ.
LM3x7 x7 ---> + 70 mA Total Typ.
----------------------
Total 1,192 mA Total Typ. ---> 11.9 Watts
D_Card Parts:
100325 -4.5V current 27 mA Typ. 37 mA Max.
+5.0V current 45 mA Typ. 65 mA Max.
TCM2620 40 mW at 300 frames per second from 5V --> 8 mA
Count half of this as analog and half as digital.
4 mA Typ.
74HCT541 +5.0V current 10 mA Typ. 15 mA Max.
LM3x7 Standing Current 10 mA Typ.
A D_Card Consists of:
100325 x3 ---> 219 mA Total Typ.
TCM2620 x1 ---> 4 mA Total Typ.
74HCT541 x3 ---> 30 mA Total Typ.
LM3x7 x3 ---> + 30 mA Total Typ.
----------------------
Total 283 mA Total Typ. ---> 2.8 Watts
Total power dissipated by the camera is:
(4 x 11.9 W) + 2.8 W = 50.4 Watts
This 50.4 Watt number assumes that the ECL 56 Ohm pull down resistors are
part of the camera and that the supply to the camera is +- 10 Volts.
If we remove the 56 Ohm pull down resistors from the camera then the
current required by the 100324's changes from:
100324 -4.5V current 45 mA Typ. 70 mA Max.
-2.0V current 114 mA Typ. 114 mA Max.
+5.0V current 25 mA Typ. 38 mA Max.
to:
100324 -4.5V current 45 mA Typ. 70 mA Max.
+5.0V current 25 mA Typ. 38 mA Max.
This reduces the power requirement of an A_Card to only 7.36 Watts.
Now the total power dissipated by the camera is:
(4 x 7.36 W) + 2.8 W = 32.2 Watts
This 32.2 Watt number assumes that the 56 Ohm ECL pull down resistors are
located at the receiving end in the VME environment and that the camera
runs from +- 10 Volt supplies.
Now the linear regulators do not really need a 5 Volt In-Out differential.
They are rated to run with a 3 volt differential. So the whole camera
could run from +- 8 Volts instead of the +- 10 Volts (except for the
internal +6V supply). This would reduce to power requirement to 80% of the
previous figure. Now the total power dissipated by the camera is:
32.2 Watts x 80% = 25.8 Watts
The 25.8 Watt number assumes receiver end 56 Ohm pull down resistors and
operation from +- 8 Volt supplies.
***************************************************************************
Now calculate calculate the power dissipation under the following conditions:
1. All of the digital stuff runs off of "remote regulated, remote
sensed" power supplies. These would need to be: +5V, -4.5V.
2. All of the analog stuff runs off of local linearly regulated supplies.
These would need to be on the A_Card: +6V_A, +5V_A, +5V_D, -5V_A.
The bulk power for these supplies is +10V and -10V.
3. The ECL 56 Ohm pull downs have been located at the receiving end to
eliminate there contribution to the power dissipation in the box on
the dewar.
So now calculate this:
Drawn
from Average
Camera Typ-Max
Box x Supply
A_Card Parts: Supply mWatt
-------- -------
100324 -4.5V current 45 mA Typ. 70 mA Max. -4.5V 259
-2.0V current 114 mA Typ. 114 mA Max. none 0
+5.0V current 25 mA Typ. 38 mA Max. +5V + 158
-----
total 417
TCM2620 40 mW at 300 frames per second from 5V --> 8 mA
Count half of this as analog and half as digital.
4 mA Typ. +10V 40
ADS-946 -5.0V current 120 mA Typ. 160 mA Max. -10V 1400
+5.0V current 220 mA Typ. 270 mA Max. +10V 2450
-----
total 3850
AD9631 -5.0V current 17 mA Typ. 21 mA Max. -10V 190
+6.0V current 17 mA Typ. 21 mA Max. +10V 190
-----
total 380
Precision -5.0V current 5 mA Typ. 8 mA Max. -10V 65
Rail-Rail +6.0V current 5 mA Typ. 8 mA Max. +10V 65
OpAmp -----
total 130
74HCT541 +5.0V current 10 mA Typ. 15 mA Max. +5V 63
LM3x7 Standing Current 10 mA Typ. +10V 100
An A_Card Consists of:
100324 x4 ---> 1668 mW Total
TCM2620 x1 ---> 40 mW Total
ADS-946 x1 ---> 3850 mW Total
AD9631 x1 ---> 380 mW Total
Precs Rail-Rail OpAmp x2 ---> 260 mW Total
74HCT541 x2 ---> 126 mW Total
LM3x7 x4 ---> + 400 mW Total
----------------------
Total 6,724 mW Total Typ. ---> 6.72 Watts
per A_Card
Drawn
from Average
Camera Typ-Max
Box x Supply
D_Card Parts: Supply mWatt
-------- -------
100325 -4.5V current 27 mA Typ. 37 mA Max. -4.5 V 144
+5.0V current 45 mA Typ. 65 mA Max. +5 V 275
-----
total 419
TCM2620 40 mW at 300 frames per second from 5V --> 8 mA
Count half of this as analog and half as digital.
4 mA Typ. +10V 40
74HCT541 +5.0V current 10 mA Typ. 15 mA Max. +5V 63
A D_Card Consists of:
100325 x3 ---> 1257 mW Total
TCM2620 x1 ---> 40 mW Total
74HCT541 x3 ---> 189 mW Total
LM3x7 x1 ---> + 100 mW Total
----------------------
Total 1,586 mW Total Typ. ---> 1.59 Watts
per A_Card
Total power dissipated by the camera is:
(4 x 6.72 W) + 1.59 W = 28.5 Watts
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Power Cable(s) from VME to Fast_IR_Camera FIRC
-------------------------------------------------
We need to transport from the VME environment to FIRC the following
voltages: +10V_A, +5V_D, -2.0V_D, -4.5V_D, -10V_A.
These will be carried in two separate shielded cables: an Analog power
cablel and a Digital power cable. The wiring of both cables is similar.
Analog Power Cable Digital Power Cable
Analog Power Cable and Digital Power Cable shields go to case ground.
22 gauge wire is about 1.65 Ohms per 100 feet
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
So the power supplies on the A_Card are:
1. +5 Volts Analog for the ADS-946 A to D converter
2. +5 Volts Digital for the ADS-946 A to D converter
3. -5 Volts Analog for the ADS-946 A to D converter and the AD9631 Op-Amp
4. +6 Volts Analog for the AD9631 Op-Amp
5. +5 Volts Analog for the TCM2620: AMPHI, COLHI, and ABAMPHI
6. +3.5 to 4.0 Volt Analog for the TCM2620 DSUB supply
7. +2.0 to 2.5 Volt Analog supply for the TCM2620 VCLAMP supply
8. +4.0 to 5.0 Volt Analog supply for the AC grounded end of the Op-Amp
feedback circuit.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
In a September mail message Jeff Kuhn said,
"I think we should worry about 40-50 watts. Our current electronics
dissipate no more than 15-20 watts immediately outside of the dewar. I
suggest we use an input and output air hose around the electronics box"
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Getting rid of the 56 Ohm pull down resistors at the camera end does save
power at the camera end but it has the disadvantage of putting a low common
mode impedance at the receiving end. This low common mode impedance at the
receiving end will cause additional loop currents to circulate at the
camera end. So we would like to move the ECL pull down back to the camera
end. How much power does this cost if this all runs off of a remote
regulated -2.0V supply ?
There are 64 signals. Each signal has a non-inverted and inverted side.
The nominal output levels are: -0.955 Volts and -1.705 Volts.
So the -0.955 Volt state draws 18.66 mA through a 56 Ohm resistor
and dissipates 19.5 mW of power in this resistor.
And the -1.705 Volt state draws 5.27 mA through a 56 Ohm resistor
and dissipates 1.55 mW of power in this resistor.
So each of the 64 signals requires (18.66 mA + 5.27 mA = 23.93 mA)
of current which is a total of 1.532 Amps of Vtt.
And each of the 64 signals dissipates (19.5 mW + 1.55 mW = 21.05 mW)
of power which is a total of 1.347 Watts in the pull down resistors.
Conclusion: An additional 1.35 Watts at the camera end is the price of
moving the pull down resistors into the camera. This would
put the total camera power dissipation right at 30 Watts.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
16-SEPT-1997
Measure the power consumed by the camera (1x D-Card, 4x A-Card, 0x Array)
at both 2 Mhz and 6 Mhz digitization rates.
6 Mhz
-4.5V_D -2.0V_D +5.0V_D -9.0V_A +9.0V_A
------- ------- ------- ------- -------
Into Choke 4.476 V 2.049 4.975 8.979 8.980
Out From Choke 4.466 V 1.990 4.950 8.954 8.948
Brick Output 5.049 V 2.986 4.909 9.173 9.274
Amps 0.66 A 1.75 0.70 0.71 1.02
2 Mhz
-4.5V_D -2.0V_D +5.0V_D -9.0V_A +9.0V_A
------- ------- ------- ------- -------
Into Choke 4.478 V 2.045 4.976 8.982 8.988
Out From Choke 4.468 V 1.983 4.950 8.957 8.956
Brick Output 5.102 V 3.028 4.782 9.131 9.382
Amps 0.66 A 1.75 0.66 0.71 1.00
The Choke input and output voltages are measured with respect to the M-Card
Ground Plane.
Voltage drop across the return chokes on the A-Card
Digital Return Choke +47 mV
Analog Return Choke -12 mV
Power dissipated in the camera (assuming nominal supply voltages and
measured currents)
-4.5V_D -2.0V_D +5.0V_D -9.0V_A +9.0V_A
------- ------- ------- ------- -------
Volts 4.50 V 2.00 5.00 9.00 9.00
Amps 0.66 A 1.75 0.70 0.71 1.02
X ------- ------- ------- ------- -------
2.97 W 3.50 3.50 6.39 9.18
\____________________________/ \________________/
9.97 W Digital 15.57 W Analog
\____________________________________________/
25.54 W Total
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
29-DEC-1997
Tests of first official Analog Power Pan that uses the Astec made in
China bricks. There are 2.2 uFd Tantalum capacitors across all of the
Supply to Sense terminals. This new Analog power pan is connected to
the Camera via 30 to 35 feet of Belden #9938 37 conductor 24 AWG cable.
Check the supply voltages on the A-Card that is furthest from the M-Card
power connector and compare this to the Analog Power Pan front panel
tip jack voltages.
Analog Power Pan
A-Card Voltage Tip Jack Voltage
-------------- ----------------
+ 9.00 + 9.19 Volts
- 9.00 - 9.25
+ 5.00 + 4.96
- 4.51 - 5.06
- 2.012 - 2.955
The new first official Analog Power Pan appears to operate OK except
the -2 V brick was oscillating at about 250 kHz at about 300 mV peak to
peak. A 1500 uFd 16 Volt aluminum capacitor was put across the output
of the -2 V brick and it quit oscillating. All sense leads are currently
connected directly to the bricks, i.e. there are no series resistors in
the sense leads yet.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
11-JAN-1998
Tests of supply voltages on the assembled system on the C130 on Friday
9-JAN-1998.
Measurement
Camera Analog on M-Card
Power Pan or A-Card at
Supply Test Points Location J1
------ ------------- ------------
+9V 9.18 V 9.03 V
-9V 9.26 9.04
+5V 4.98 5.02
-2V 2.932 2.010
-4.5V 5.04 4.53
VME Power Pan
Supply Test Points
------ -------------
+5.0V 5.05 V
+3.3V 3.324
-2.0V 2.044
-4.5V 4.55
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
6-FEB-1998
Tests of supply voltages on the assembled system on the C130 on Friday
6-FEB-1998 after the Analog Supply had been adjusted for use with the
6.5V 1st stage reference voltage.
6-FEB-1998
11-JAN-1998 6-FEB-1998 Measurement
Camera Analog Camera Analog on M-Card
Power Pan Power Pan or A-Card at
Supply Test Points Test Points Location J1
------ ------------- ------------- ------------
+9V 9.18 V 9.69 V . V
-9V 9.26 9.31 . NOT
+5V 4.98 4.93 . CHECKED
-2V 2.932 2.949 .
-4.5V 5.04 5.05 .