Difference between revisions of "OPTOFAST-2"

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# GND (Out)
 
# GND (Out)
 
# GND (Out)
 
# GND (Out)
 +
 +
== Calculations ==
 +
 +
=== Power Domains ===
 +
 +
* Each side of the card has its own independent power domain
 +
* Each side of the card receives external power
 +
* Each side can be powered with 3.3V or 5V
 +
 +
=== Input Drive Calculations ===
 +
 +
* The input side of the card has optional drive transistors
 +
** 10K ohm resistors into the transistor base allows for wide input voltage range
 +
** If the input signals are 5V, then the input current is 500uA
 +
 +
=== Output Drive Calculations ===
 +
 +
* Output side of the card has 4.7K pullups
 +
** These determine the rise time of the output
 +
 +
These are the calculations for the output current:
 +
 +
{| class="wikitable"
 +
! Input Side
 +
!
 +
!
 +
!
 +
!
 +
|-
 +
| Vcc (IN)
 +
| 5
 +
| V
 +
|
 +
|
 +
|-
 +
| Vf
 +
| 1.2
 +
| V
 +
|
 +
|
 +
|-
 +
| Vres
 +
| 3.8
 +
| V
 +
|
 +
|
 +
|-
 +
| Res
 +
| 150
 +
| Ohms
 +
|
 +
|
 +
|-
 +
| If
 +
| 25.33
 +
| mA
 +
|
 +
|
 +
|-
 +
| CT
 +
| 0.2
 +
| A/A
 +
|
 +
|
 +
|-
 +
| Iout max
 +
| 5.07
 +
| mA
 +
|
 +
|
 +
|-
 +
| Output side
 +
|
 +
|
 +
|
 +
|
 +
|-
 +
| Vcc (OUT)
 +
| 5
 +
| V
 +
| 3.3
 +
| V
 +
|-
 +
| Rballast
 +
| 4.7
 +
| Kohms
 +
| 4.7
 +
| Kohms
 +
|-
 +
| Iballast
 +
| 1.06
 +
| mA
 +
| 0.70
 +
| mA
 +
|-
 +
| IL out avail
 +
| 4.00
 +
| mA
 +
| 4.36
 +
| mA
 +
|-
 +
|
 +
|
 +
|
 +
|
 +
|
 +
|-
 +
| Input Side
 +
|
 +
|
 +
|
 +
|
 +
|-
 +
| Vcc (IN)
 +
| 3.3
 +
| V
 +
|
 +
|
 +
|-
 +
| Vf
 +
| 1.2
 +
| V
 +
|
 +
|
 +
|-
 +
| Vres
 +
| 2.1
 +
| V
 +
|
 +
|
 +
|-
 +
| Res
 +
| 150
 +
| Ohms
 +
|
 +
|
 +
|-
 +
| If
 +
| 14.00
 +
| mA
 +
|
 +
|
 +
|-
 +
| CT
 +
| 0.2
 +
| A/A
 +
|
 +
|
 +
|-
 +
| Iout max
 +
| 2.80
 +
| mA
 +
|
 +
|
 +
|-
 +
| Output side
 +
|
 +
|
 +
|
 +
|
 +
|-
 +
| Vcc (OUT)
 +
| 5
 +
| V
 +
| 3.3
 +
| V
 +
|-
 +
| Rballast
 +
| 4.7
 +
| Kohms
 +
| 4.7
 +
| Kohms
 +
|-
 +
| Iballast
 +
| 1.06
 +
| mA
 +
| 0.70
 +
| mA
 +
|-
 +
| IL out avail
 +
| 1.74
 +
| mA
 +
| 2.10
 +
| mA
 +
|-
 +
|}
  
 
== Test Card Measurements ==
 
== Test Card Measurements ==
Line 141: Line 327:
  
 
=== Test Results===
 
=== Test Results===
−
* Channel Fast/Slow TransBuff/Direct Input Rise/Fall Time(uS)
+
 
−
1 Slow Transistor Buffer Fall 28.6
+
{| class="wikitable"
−
1 Slow Transistor Buffer Rise 1.8
+
! Channel
−
2 Fast Transistor Buffer Fall 6.68
+
! Fast/Slow
−
2 Fast Transistor Buffer Rise 3.6
+
! TransBuff/Direct
−
3 Slow Direct Input Fall 1.84
+
! Input Rise/Fall
−
3 Slow Direct Input Rise 27.4
+
! Time(uS)
−
4 Fast Direct Input Fall 4.24
+
|-
−
4 Fast Direct Input Rise 5.28
+
| 1
−
</pre>
+
| Slow
 +
| Transistor Buffer
 +
| Fall
 +
| 28.6
 +
|-
 +
| 1
 +
| Slow
 +
| Transistor Buffer
 +
| Rise
 +
| 1.8
 +
|-
 +
| 2
 +
| Fast
 +
| Transistor Buffer
 +
| Fall
 +
| 6.68
 +
|-
 +
| 2
 +
| Fast
 +
| Transistor Buffer
 +
| Rise
 +
| 3.6
 +
|-
 +
| 3
 +
| Slow
 +
| Direct Input
 +
| Fall
 +
| 1.84
 +
|-
 +
| 3
 +
| Slow
 +
| Direct Input
 +
| Rise
 +
| 27.4
 +
|-
 +
| 4
 +
| Fast
 +
| Direct Input
 +
| Fall
 +
| 4.24
 +
|-
 +
| 4
 +
| Fast
 +
| Direct Input
 +
| Rise
 +
| 5.28
 +
|-
 +
|}
  
 
=== Observations ===
 
=== Observations ===
Line 197: Line 430:
  
 
[[File:Ch4-Fast-Direct-InRise.png]]
 
[[File:Ch4-Fast-Direct-InRise.png]]
 +
 +
== Factory Test ==
 +
 +
* [http://land-boards.com/blwiki/index.php?title=Arduino_Based_Test_Station ODAS Card Test Station]
 +
** Running [https://github.com/land-boards/lb-Arduino-Code/tree/master/LBCards/ODAS/ODASTESTER ODASTESTER code]
 +
* [[DB37RIBBON]]
 +
* Cable set
 +
* PC running PuTTY
 +
** 9600 baud
 +
** USB-C cable
 +
*** USB connected to PC and USB-C connected to [[BLACK-PILL-HUB]]
 +
* Powered through the USB-C connector on the [[STM32 Black Pill]]
 +
 +
<pre>
 +
Checking if EEPROM is present on UUT...EEPROM is not present on UUT
 +
Count of I2C devices in range 0x20-0x27 on UUT = 0
 +
No external I2C mux card
 +
Select the board type (Other)
 +
4 - OPTOFast/Small Non-Inverting board
 +
5 - OPTOFast/Small Inverting board
 +
6 - OptoFastBi board
 +
Select board > 5
 +
C=Card Tests, D=Direct, E=EEPROM, I=access Internal DIGIO32
 +
L=Loop/S=Single, T=Test, B=Bounce LEDs, I=UUT Int'l Tests, X=eXit sub-menu
 +
Testing UUT = Opto Inc
 +
Error on port 0 Expected Low
 +
Test PASS = 0, FAIL = 1
 +
</pre>
  
 
== Layout ==
 
== Layout ==

Latest revision as of 20:46, 30 March 2023

Tindie-mediums.png

OptoFast-2-P447-720px.jpg

Features

  • Opto-Isolator card
  • 4-Channels
  • 4N25 Optoisolators
  • Input /Output isolation
  • Transistor driver for Opto LED reduces required drive from 10 mA to under 500 uA
  • Input channels share their own common VCC/Ground
  • Output channels share their own common Vcc/Ground
  • 8-pin header for input
  • 8-pin header for output
  • Configuration Options
    • Speed enhanced
    • Bypass Input transistors
    • Remove Output collector resistors
  • 49x49mm
  • (4) 4-40 mounting holes

Schematic (One channel)

OPTOFAST-2-Schematic-TransIn.PNG

  • U1 represents U1-U4 (channels 1-4)
  • Q1 represents Q1-Q4 (channels 1-4)
  • R1 (VCC) represents R1,R4,R7,R10 (channels 1-4)
  • R2 (DIR) represents R2,R5,R8,R11 (channels 1-4)
  • R3 (BASE) represents R3,R6,R8,R12 (channels 1-4)
  • R13 (FAST) represents R13-R16 (channels 1-4)
  • R17 (COLL) represents R17-R20 (channels 1-4)

Input Options

  • Refer to schematic for impact of options

Use Input Transistor - Standard Option

  • Common VCC in option
  • Install transistor Q1
  • R1 = 150
    • LED current is 3.5V/150 Ohms = 23 mA
    • CTR = .20, 4.7 mA
  • R2 = Do not populate
  • R3 = 10K
    • Base drive ~ (Vin - 0.7V)/R3
    • At 5V drive this is 4.3V/R3
      • Using R3=10K at 5V this is 0.43mA Ib
      • HFE (MMBT3904) = 100 min
      • That is potentially 43 mA (in the switching range of the transistor)
        • Collector resistor and LED voltage drop are current limiter
    • At 3.3V drive this is (3.3-0.7)/10K = .26mA Ib
      • HFE = 100 min
      • That is 26 mA (in the switching range of the transistor)
  • H1 do not short

Direct Drive - Special Option

OPTOFAST-2-Schematic-Direct.PNG

  • Do not install Q1
  • Do not install R1
  • R2 = 150
    • Input current = LED current = 3.5V/150 Ohms = 23 mA
  • Do not install R3
  • Do not install Q1
  • Short H1

Output Options

Standard Output

  • R17 = 1.2K
    • 5V/1.2K = 4.1mA of output transistor B-E current
    • Leaves 4.7-4.1 mA = 600 uA of output low current

Open Collector Output - Special Option

  • Do not install R17

Fast Option - Standard

  • R13 = 20K (empirically determined from the scope eye)

Connectors

P1 - Input

8-pin, right angle, 0.1" pitch

  1. Vcc (In)
  2. Vcc (In)
  3. IN 1
  4. IN 2
  5. IN 3
  6. IN 4
  7. GND (In)
  8. GND (In)

P2 - Output

8-pin, right angle, 0.1" pitch

  1. Vcc (Out)
  2. Vcc (Out)
  3. OUT 1
  4. OUT 2
  5. OUT 3
  6. OUT 4
  7. GND (Out)
  8. GND (Out)

Calculations

Power Domains

  • Each side of the card has its own independent power domain
  • Each side of the card receives external power
  • Each side can be powered with 3.3V or 5V

Input Drive Calculations

  • The input side of the card has optional drive transistors
    • 10K ohm resistors into the transistor base allows for wide input voltage range
    • If the input signals are 5V, then the input current is 500uA

Output Drive Calculations

  • Output side of the card has 4.7K pullups
    • These determine the rise time of the output

These are the calculations for the output current:

Input Side
Vcc (IN) 5 V
Vf 1.2 V
Vres 3.8 V
Res 150 Ohms
If 25.33 mA
CT 0.2 A/A
Iout max 5.07 mA
Output side
Vcc (OUT) 5 V 3.3 V
Rballast 4.7 Kohms 4.7 Kohms
Iballast 1.06 mA 0.70 mA
IL out avail 4.00 mA 4.36 mA
Input Side
Vcc (IN) 3.3 V
Vf 1.2 V
Vres 2.1 V
Res 150 Ohms
If 14.00 mA
CT 0.2 A/A
Iout max 2.80 mA
Output side
Vcc (OUT) 5 V 3.3 V
Rballast 4.7 Kohms 4.7 Kohms
Iballast 1.06 mA 0.70 mA
IL out avail 1.74 mA 2.10 mA

Test Card Measurements

OptoFast-TestSetup-720px.jpg

Setup

  • Goal was to determine the performance of the OPTOFAST card
  • 5V operation
  • Same 5V input/output power supply
  • Each of the channels were configured uniquely/individually
  • MHS-5200A - Digital DDS Dual-channel Signal Generator
    • 1 KHz square wave
    • 5V signal level
  • Single channel checked at a time
  • Oscilloscope
    • Rigol DS1054Z
    • 50 MHz
    • Ultra Sigma software used for screen captures

Notes

  • Note that the input buffer transistor inverts the signal
  • Built a card that has four different configurations
  • Options
    • Fast/Slow
    • Direct drive input LED/Transistor Buffered input

Test Results

Channel Fast/Slow TransBuff/Direct Input Rise/Fall Time(uS)
1 Slow Transistor Buffer Fall 28.6
1 Slow Transistor Buffer Rise 1.8
2 Fast Transistor Buffer Fall 6.68
2 Fast Transistor Buffer Rise 3.6
3 Slow Direct Input Fall 1.84
3 Slow Direct Input Rise 27.4
4 Fast Direct Input Fall 4.24
4 Fast Direct Input Rise 5.28

Observations

  • Input Transistor effect
    • Value of the input transistor is that does not require a high drive level input
    • The input transistor has very little effect on speed - a couple hundred nS slower than direct drive
    • The inversion effect of the input transistor moves the "slow" time around
    • Downside of the input transistor is that it has less noise immunity since the transistor turns on at 0.6V vs the internal LED in the optocoupler at 1.5V?
  • Output "fast" circuit
    • Output pullup of 4.7K affects the rise time of the output
    • The fast is faster, but not in some conditions
    • Average of rise/fall is better
    • Transistor buffer instance rise input is slower with the fast output
    • Fast output helps the output rise time

Ch1-Slow-NPNBuffer-InFall

Ch1-Slow-NPNBuffer-InFall.png

Ch1-Slow-NPNBuffer-InRise

Ch1-Slow-NPNBuffer-InRise.png

Ch2-Fast-NPNBuffer-InFall

Ch2-Fast-NPNBuffer-InFall.png

Ch2-Fast-NPNBuffer-InRise

Ch2-Fast-NPNBuffer-InRise.png

Ch3-Slow-Direct-InFall

Ch3-Slow-Direct-InFall.png

Ch3-Slow-Direct-InRise

Ch3-Slow-Direct-InRise.png

Ch4-Fast-Direct-InFall

Ch4-Fast-Direct-InFall.png]

Ch4-Fast-Direct-InRise

Ch4-Fast-Direct-InRise.png

Factory Test

Checking if EEPROM is present on UUT...EEPROM is not present on UUT
Count of I2C devices in range 0x20-0x27 on UUT = 0
No external I2C mux card
Select the board type (Other)
4 - OPTOFast/Small Non-Inverting board
5 - OPTOFast/Small Inverting board
6 - OptoFastBi board
Select board > 5
C=Card Tests, D=Direct, E=EEPROM, I=access Internal DIGIO32
L=Loop/S=Single, T=Test, B=Bounce LEDs, I=UUT Int'l Tests, X=eXit sub-menu
Testing UUT = Opto Inc
Error on port 0 Expected Low
Test PASS = 0, FAIL = 1

Layout

OPTOFAST-2 PWB.PNG

Assembly Sheet

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