Analog Computer - 4-Quadrant Division Module

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This repository provides a 4-Quadrant Division Module for analog computing applications. The design incorporates two independent 4-Quadrant Division circuits, each equipped with an output signal indicator and overload indicator to monitor operation.
The overload indicator activates if the output exceeds the machine unit of $\pm10V$ and the output signal indicator is red or green proportional to the negative or positive output voltage. This display enables easy diagnostic of an analog computing patch.

Module Schematic

The schematic is divided into multiple sections for the ease of understanding. All functional modules like power management, division and error-indication have their own page in the circuit diagram.

4-Quadrant Divider:
The division is accomplished by having the multiplier in the feedback path of an operational amplifier, thus solving for $-X/|Y|$. To cover all 4 Quadrants of the input, we first have a section to get the absolute Value of of $Y$, which is fed into the division. The output then corrects for the sign of the input $Y$ and inverts the signal when needed. Thus the Output is $X/Y$, covering all 4 Quadrants of the input. To enable easy diagnostic and debugging of an analog patch, the LED indicator displays the polarity and size of the output signal.

Overload Indicator:
The output signal of each seperate division circuit is compared to a reference voltage of $+10V$ and $-10V$. A red LED indicates the value of a division is exceeding the machine value of $\pm10V$. Which can easiliy happen when the absolute value of $Y$ gets small.

The Error Indicator for each individual Output takes a lot of extra space and components, but I consider it worth it for error hunting in an analog patch.

References:
The circuit is mostly based on the THAT of Anabrid GmbH, which has its circuit diagram openly available at their github repository Anabrid. Also a special mention goes to Michael Koch who has put together a large collection of analog computing circuits in his book on the THAT Analog Computer.

BOM

Main Module:

Reference	Value	Footprint	QUANTITY
C1,C2	10u	1206 / 3216Metric	2
C3-C27	100n	1206 / 3216Metric	25
D1	12V_GREEN	1206 / 3216Metric	1
D2	-12V_RED	1206 / 3216Metric	1
IC1,IC2	AD633	SOIC-8	2
J1	Conn_01x14_Pin	PinHeader_1x14_P2.54mm_Vertical	1
J2	Conn_02x05_Odd_Even	PinHeader_2x05_P2.54mm_Vertical	1
Q1	PMV250EPEA	SOT-23	1
Q2	PMV450ENEA	SOT-23	1
R1,R2	5k6	1206 / 3216Metric	2
R3,R4,R8-R10,R12,R14,R15,R19,R39,R40,R44-R46,R48,R50,R51,R55	100k (0.1p)	1206 / 3216Metric	18
R5,R13,R41,R49	50k	1206 / 3216Metric	4
R6,R16,R25,R28,R42,R52	510k	1206 / 3216Metric	6
R7,R17,R43,R53	470	1206 / 3216Metric	4
R18,R54	25k (0.1p)	1206 / 3216Metric	2
R20,R56	3k9	1206 / 3216Metric	2
R21,R24,R27,R32,R33,R35-R37	100k	1206 / 3216Metric	8
R22,R26,R31,R34	10k	1206 / 3216Metric	4
R23,R29	15k	1206 / 3216Metric	2
R30,R38	4k	1206 / 3216Metric	2
U1,U2	VCAN16A2	SOT23-3	2
U3,U6,U11,U14	DG419BDY-E3	SOIC-8	4
U4,U5,U9,U12,U13	TLE2074IDWR	SOIC-14	5
U7	LM339DR	SOIC-14	1
U8	CD40106BM96	SOIC-14	1
U10	LM4040, 10V	SOT-23	1

Middleplate:

Reference	Value	Footprint	QUANTITY
D1	IND_X1/Y1	LED_D3.0mm_FlatTop	1
D2	ERROR_1	LED_D3.0mm_FlatTop	1
D3	IND_X2/Y2	LED_D3.0mm_FlatTop	1
D4	ERROR_2	LED_D3.0mm_FlatTop	1
J1	Conn_01x14_Socket	PinSocket_1x14_P2.54mm_Vertical	1
U1-U3	VCAN16A2-03S-E3-08	SOT23-3	3

List of special Components:

• OP-amp: TLE2074IDWR (Upgrade of the TL074HIDR)
• analog IC switch: DG456EY, DG419BDY-E3, DG403DYZ
• 10V voltage reference: LM4040CIM3-10.0/NOPB
• comparator: LM339DR
• logic inverter: CD40106BM96

Altnernatives to consider:

• Multiplier: AD633JRZ to AD835ARZ

License

This work is published under the CERN Open Hardware Licence Version 2 - Strongly Reciprocal