Analog Squarer {Y=X^2} 1 Quardrant

[Harry D]

I have looked at the AD835 and other 4-Q multipliers but they are costly and power hogs. I need a simpler (+/-5% accuracy [-40C to 105C]) design thatwill be used in a high reliability product. Input range of 0.05V to 1.70V with a bandwidth of dc to at least 1.0MHz. Simplicity, small size, low power <50mW, SM implication and cost are a plus. I need some starter ideas for me to complete the design.

Cheers,
Harry

 

[Spehro Pefhany]

I have looked at the AD835 and other 4-Q multipliers but they are costly and power hogs. I need a simpler (+/-5% accuracy [-40C to 105C]) design that will be used in a high reliability product. Input range of 0.05V to 1.70V with a bandwidth of dc to at least 1.0MHz. Simplicity, small size, low power <50mW, SM implication and cost are a plus. I need some starter ideas for me to complete the design.

Cheers,
Harry

x^2 = exp(2*ln(x))

log-antilog with thermistor temperature compensation?


Best regards,
Spehro Pefhany

 

[Klaus Kragelund]

I have looked at the AD835 and other 4-Q multipliers but they are costly and power hogs. I need a simpler (+/-5% accuracy [-40C to 105C]) design that will be used in a high reliability product. Input range of 0.05V to 1.70Vwith a bandwidth of dc to at least 1.0MHz. Simplicity, small size, low power <50mW, SM implication and cost are a plus. I need some starter ideas forme to complete the design.

Find a microcontroller with a 10Msa ADC and do the multiply in that. Will cost you max 1 USD. Then you can do more complex arithmetics


Regards

Klaus

 

[Harry D]

I have looked at the AD835 and other 4-Q multipliers but they are costly and power hogs. I need a simpler (+/-5% accuracy [-40C to 105C]) design that will be used in a high reliability product. Input range of 0.05V to 1.70Vwith a bandwidth of dc to at least 1.0MHz. Simplicity, small size, low power <50mW, SM implication and cost are a plus. I need some starter ideas forme to complete the design.



Cheers,

Harry

 

[Harry D]

The MC1594 must be one of JT's old designs using Vac tubes. Normal PS is +/-15V with +/-4.0V of CM dead range so worthless in +/-5V unit.
i shoulder added +/-5V operation is a requirement.

Regards,
Harry

 

[Harry D]

On Fri, 16 Nov 2012 16:03:29 -0800 (PST), Harry D

A nonlinear segment circuit would probably work at this speed and

accuracy.





--



John Larkin Highland Technology Inc

www.highlandtechnology.com jlarkin at highlandtechnology dot com



Precision electronic instrumentation

Picosecond-resolution Digital Delay and Pulse generators

Custom timing and laser controllers

Photonics and fiberoptic TTL data links

VME analog, thermocouple, LVDT, synchro, tachometer

Multichannel arbitrary waveform generators

I agree John, a nonlinear circuit would be simpler in my design. If I could design a circuit who's output would be 1/Vin with all my other requirements, that would be perfect. Trimming is not allowed, got to work in production, no tweaking, every time.
Regards,
Harry

 

[whit3rd]

I have looked at the AD835 and other 4-Q multipliers but they are costly and power hogs. I need a simpler (+/-5% accuracy [-40C to 105C]) design

How about LM13700 (figure 6 on the datasheet is a multiplier)?
It's not happy at your temperature extremes, but it IS cheap
and runs on fleapower.

 

[Harry D]

I have looked at the AD835 and other 4-Q multipliers but they are costly and power hogs. I need a simpler (+/-5% accuracy [-40C to 105C]) design

How about LM13700 (figure 6 on the datasheet is a multiplier)?

It's not happy at your temperature extremes, but it IS cheap

and runs on fleapower.

I have looked at the AD835 and other 4-Q multipliers but they are costly and power hogs. I need a simpler (+/-5% accuracy [-40C to 105C]) design

How about LM13700 (figure 6 on the datasheet is a multiplier)?

It's not happy at your temperature extremes, but it IS cheap

and runs on fleapower.

Yea but that +/- 15v IC will not operate in a +/-5V domain.

Thanks,
Harry

 

[legg]

I have looked at the AD835 and other 4-Q multipliers but they are costly and power hogs. I need a simpler (+/-5% accuracy [-40C to 105C]) design that will be used in a high reliability product. Input range of 0.05V to 1.70V with a bandwidth of dc to at least 1.0MHz. Simplicity, small size, low power <50mW, SM implication and cost are a plus. I need some starter ideas for me to complete the design.

Cheers,
Harry

Was going to say RC4200, but Fairchild dropped the ball after taking
it from Raytheon.

So:

http://electronicdesign.com/article/power/what-s-all-this-multiplier-divider-stuff-anyhow-

RL

 

[Fred Bartoli]

Harry D a écrit :

I have looked at the AD835 and other 4-Q multipliers but they are costly and power hogs. I need a simpler (+/-5% accuracy [-40C to 105C]) design that will be used in a high reliability product. Input range of 0.05V to 1.70V with a bandwidth of dc to at least 1.0MHz. Simplicity, small size, low power <50mW, SM implication and cost are a plus. I need some starter ideas for me to complete the design.

Does BW need to be 1MHz on both inputs?

If not you could use a digipot with a small uc with an integrated ADC
(or build your own with internal comparator) for the slow input.

 

[Fred Bartoli]

Fred Bartoli a écrit :

Harry D a écrit :

I have looked at the AD835 and other 4-Q multipliers but they are
costly and power hogs. I need a simpler (+/-5% accuracy [-40C to
105C]) design that will be used in a high reliability product. Input
range of 0.05V to 1.70V with a bandwidth of dc to at least 1.0MHz.
Simplicity, small size, low power <50mW, SM implication and cost are a
plus. I need some starter ideas for me to complete the design.

Does BW need to be 1MHz on both inputs?

If not you could use a digipot with a small uc with an integrated ADC
(or build your own with internal comparator) for the slow input.

Sorry I missed the squarer part, only retaining the multiplier.

Forget that.

 

[P E Schoen]

"Harry D" wrote in message

I have looked at the AD835 and other 4-Q multipliers but they are costly
and power

< hogs. I need a simpler (+/-5% accuracy [-40C to 105C]) design that will be
used in a

high reliability product. Input range of 0.05V to 1.70V with a bandwidth
of dc to at
least 1.0MHz. Simplicity, small size, low power <50mW, SM implication and
cost are a
plus. I need some starter ideas for me to complete the design.

You might consider a multiplying DAC. But they are also expensive and you
would need an A/D as well as (in some cases) an SPI interface for the
digital input. Here is one:
http://www.analog.com/static/imported-files/data_sheets/AD5543_5553.pdf

The AD633 multiplier is reasonable cost but minimum +/- 8V:
http://www.analog.com/static/imported-files/data_sheets/AD633.pdf

I have about 15-20 pieces of AD534 in 14 pin gold/ceramic DIP I can offer
for well under the present list prices, but it is also minimum +/- 8V.

The best option may be a PIC with dual simultaneous high speed A/D and
hardware multiplier. The output could be PWM or digital into an external
DAC.

You might be able to use the diode square law function as described here:
http://www.philbrickarchive.org/us3373293.pdf

or more recently:
http://www.edn.com/file/22730-91699di.pdf

Another technique is using PWM where the amplitude as well as the pulse
width are derived from the signal you want to multiply.
http://www.journal.kmutnb.ac.th/journal/182910255015101.pdf

Also look at the LT2940, which uses a multiplier for power measurement:
http://www.newark.com/linear-technology/lt2940cms-pbf/ic-power-current-monitor-msop-12/dp/52R9872
http://cds.linear.com/docs/Datasheet/2940f.pdf
http://cds.linear.com/docs/LT Journal/LTJournal-V20N2-01-df-LT2940-Mitchell_Lee.pdf

This old post may help:
http://sci.tech-archive.net/Archive/sci.electronics.basics/2006-08/msg00155.html

Paul

 

[Robert Baer]

I have looked at the AD835 and other 4-Q multipliers but they are costly and power hogs. I need a simpler (+/-5% accuracy [-40C to 105C]) design that will be used in a high reliability product. Input range of 0.05V to 1.70V with a bandwidth of dc to at least 1.0MHz. Simplicity, small size, low power<50mW, SM implication and cost are a plus. I need some starter ideas for me to complete the design.

Cheers,
Harry

A single diode,properly biased is fairly decent square law for a
small range.
Use a matrix with resistors; in the old analog daze (40+ years ago)
they were called DFGs.

 

[Bill Sloman]

Three logic inverters in series, with resistor feedback and resistor to the
input. Makes voltage to frequency convertor with square law dependence. Then
a monostable to convert back F to V. One logic IC that's all it takes.

Interesting. He wants 1MHz and 5% accuracy, so the three inverters
have to run faster than 20MHz with a 1.7V input Might still be a power
hog.

 

[whit3rd]

On Saturday, November 17, 2012 10:18:06 AM UTC-8, whit3rd wrote:

Yea but that +/- 15v IC will not operate in a +/-5V domain.

It's tested at +/- 15V, but it works fine down to 2V or so.
Other OTA designs (RCA/Intersil's old CA3080) were recommended
down to +/- 2V.

 

[TheGlimmerMan]

I have looked at the AD835 and other 4-Q multipliers but

they are costly and power hogs. I need a simpler
(+/-5% accuracy [-40C to 105C]) design that will be used
in a high reliability product. Input range of 0.05V to 1.70V
with a bandwidth of dc to at least 1.0MHz. Simplicity, small
size, low power <50mW, SM implication and cost are a plus.
I need some starter ideas for me to complete the design.

Cheers,
Harry

x^2 = exp(2*ln(x))

log-antilog with thermistor temperature compensation?


Best regards,
Spehro Pefhany

Use APSK (Amplitude and Phase Shifted Keying).

 

[Jasen Betts]

I have looked at the AD835 and other 4-Q multipliers but they are

costly and power hogs. I need a simpler (+/-5% accuracy [-40C to
105C]) design that will be used in a high reliability product. Input
range of 0.05V to 1.70V with a bandwidth of dc to at least 1.0MHz.
Simplicity, small size, low power<50mW, SM implication and cost are a
plus. I need some starter ideas for me to complete the design.

Cheers,
Harry

A single diode,properly biased is fairly decent square law for a
small range.
Use a matrix with resistors; in the old analog daze (40+ years ago)
they were called DFGs.

but that temperature range (400K +/- 20%) may not play well with
the required +/- 5% accuracy

the 145 degree range is worth about 290mV of bias

 

[legg]

I have looked at the AD835 and other 4-Q multipliers but they are costly and power hogs. I need a simpler (+/-5% accuracy [-40C to 105C]) design that will be used in a high reliability product. Input range of 0.05V to 1.70V with a bandwidth of dc to at least 1.0MHz. Simplicity, small size, low power <50mW, SM implication and cost are a plus. I need some starter ideas for me to complete the design.

Cheers,
Harry

What precisely are you trying to do? If you don't need full
4-quadrant, there are games you can play with multi-transistor
devices, such as the MAT-xx series from Analog Devices.

...Jim Thompson

http://electronicdesign.com/article/power/what-s-all-this-multiplier-divider-stuff-anyhow-

RL

 

[Harry D]

What precisely are you trying to do? If you don't need full

4-quadrant, there are games you can play with multi-transistor

devices, such as the MAT-xx series from Analog Devices.



...Jim Thompson

--

Jim, As my question states, I only need one quadrant, the first or third, both inputs tied together.
I am trying to keep a MOSFET on for as long as possible, from releasing smoke on overload conditions, so tracking the I^2*T constant of FET and also need a temperature term which is strait forward. The FET current changes 10:1 so the "time on" changes 1:100.

Regards,
Harry

 

[Tim Williams]

Would it suffice to do it bolometrically?

Feed the current into a PTC (perhaps a silicon PTC so it has the same
tempco!) and monitor its resistance in real time. Turn off when it's too
high.

You can of course use the MOSFETs themselves for this, but you need to be
able to sense the drain voltage.

Tim

--
Deep Friar: a very philosophical monk.
Website: http://seventransistorlabs.com

What precisely are you trying to do? If you don't need full

4-quadrant, there are games you can play with multi-transistor

devices, such as the MAT-xx series from Analog Devices.



...Jim Thompson

--

Jim, As my question states, I only need one quadrant, the first or third,
both inputs tied together.
I am trying to keep a MOSFET on for as long as possible, from releasing
smoke on overload conditions, so tracking the I^2*T constant of FET and
also need a temperature term which is strait forward. The FET current
changes 10:1 so the "time on" changes 1:100.

Regards,
Harry