Electronic Schematics (alt.binaries.schematics.electronic) A place to show and share your electronics schematic drawings.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
external usenet poster
 
Posts: 2,181
Default Oscillator Proposal

Oscillator Proposal...

Suppose I have a series RLC, one end grounded, the other end driven by
a chip, how might I make that into an oscillator?

All wild ideas accepted... this is for a custom chip.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
  #2   Report Post  
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
external usenet poster
 
Posts: 635
Default Oscillator Proposal

On 3/14/2015 1:07 PM, Jim Thompson wrote:
Oscillator Proposal...

Suppose I have a series RLC, one end grounded, the other end driven by
a chip, how might I make that into an oscillator?

All wild ideas accepted... this is for a custom chip.

...Jim Thompson


Series RLC is harder than parallel, because to leading order there's no
signal on the pin at resonance. (If it were parallel, you could do a
single-ended version of the MC1648, which you may have heard of.)

You need to arrange a negative resistance at the pin, which isn't hard
to do, and use the AC current to drive the next stage.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net
  #3   Report Post  
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
external usenet poster
 
Posts: 2,181
Default Oscillator Proposal

On Sat, 14 Mar 2015 13:36:39 -0400, Phil Hobbs
wrote:

On 3/14/2015 1:07 PM, Jim Thompson wrote:
Oscillator Proposal...

Suppose I have a series RLC, one end grounded, the other end driven by
a chip, how might I make that into an oscillator?

All wild ideas accepted... this is for a custom chip.

...Jim Thompson


Series RLC is harder than parallel, because to leading order there's no
signal on the pin at resonance. (If it were parallel, you could do a
single-ended version of the MC1648, which you may have heard of.)


Gee! That part number sure sounds familiar ;-)


You need to arrange a negative resistance at the pin, which isn't hard
to do, and use the AC current to drive the next stage.

Cheers

Phil Hobbs


I was fretting over not wanting a DC path to ground, but maybe that
can be minimized.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
  #4   Report Post  
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
external usenet poster
 
Posts: 635
Default Oscillator Proposal

On 3/14/2015 2:13 PM, Jim Thompson wrote:
On Sat, 14 Mar 2015 13:36:39 -0400, Phil Hobbs
wrote:

On 3/14/2015 1:07 PM, Jim Thompson wrote:
Oscillator Proposal...

Suppose I have a series RLC, one end grounded, the other end driven by
a chip, how might I make that into an oscillator?

All wild ideas accepted... this is for a custom chip.

...Jim Thompson


Series RLC is harder than parallel, because to leading order there's no
signal on the pin at resonance. (If it were parallel, you could do a
single-ended version of the MC1648, which you may have heard of.)


Gee! That part number sure sounds familiar ;-)


You need to arrange a negative resistance at the pin, which isn't hard
to do, and use the AC current to drive the next stage.

Cheers

Phil Hobbs


I was fretting over not wanting a DC path to ground, but maybe that
can be minimized.

...Jim Thompson


Well, if it's series, you can bias the pin anyplace you like. All sorts
of RF parts do that, e.g. the AD9956 DDS/PLL chip, which I'm working
with at the moment. I had to dig out the demo board schematic to figure
out how to drive all the differential inputs...the datasheet is a vast
wasteland.

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net
  #5   Report Post  
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
external usenet poster
 
Posts: 29
Default Oscillator Proposal

Done it many times, as an industrially important process: drive it with a
voltage and phase lock on current. Or for a general resistance source
(rather than ideal voltage source), you'll assume drive voltage (internal
clock) and measure the pin voltage to infer current. Under the
restriction Rds(on) sqrt(L/C), but not by too much, so that the signal
is not too small, nor the Q too low.

This will likely restrict what range of L, C can be used, since you get Q
* VCC volts on them and Rds(on) ~ 50 ohms for average HC scale CMOS. And
I(pin) 10mA or whatever, and probably quite a bit below that if it's a
low power application.

Maybe not as bad if it's a low voltage CMOS process where you can get low
resistance cheaply, but then you need another supply (but hey... maybe
make it variable and add AGC?). Or maybe it's reasonable to build a low
impedance analog output pin, so the amplitude is small (optionally
variable), and low impedance.

You could also do what every crystal ever does: add a loading cap, so your
circuit effectively spans a capacitive divider that's part of the resonant
capacitor. Crystals having the unique distinction of extremely large
inductance and extremely small capacitance (the motional equivalent
components), so that the impedance is still rather high (~kohms); a low
impedance resonator would need a respectively large loading cap.

If you need a "discrete"* style oscillator (a few transistors and
resistors rather than an entire loop), it should be fruitful to look at
the V-I transform of a traditional parallel resonant circuit.

*Funny way to put it, since it's going inside a chip...

Tim

--
Seven Transistor Labs
Electrical Engineering Consultation
Website: http://seventransistorlabs.com

"Jim Thompson" wrote
in message ...
Oscillator Proposal...

Suppose I have a series RLC, one end grounded, the other end driven by
a chip, how might I make that into an oscillator?

All wild ideas accepted... this is for a custom chip.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.





  #6   Report Post  
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
external usenet poster
 
Posts: 732
Default Oscillator Proposal

On Sat, 14 Mar 2015 10:07:50 -0700, Jim Thompson
wrote:

Oscillator Proposal...

Suppose I have a series RLC, one end grounded, the other end driven by
a chip, how might I make that into an oscillator?

All wild ideas accepted... this is for a custom chip.

...Jim Thompson


Hmmm. RLC is a 'short' to GND How about make the circuitry so noisy that
the RLC shorts EVERYTHING BUT the noise and the circuit just 'looks' like
it oscillates? I mean narrowband noise is an oscillator output, right?
  #7   Report Post  
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
external usenet poster
 
Posts: 231
Default Oscillator Proposal

On Sat, 14 Mar 2015 10:07:50 -0700, Jim Thompson
wrote:

Oscillator Proposal...

Suppose I have a series RLC, one end grounded, the other end driven by
a chip, how might I make that into an oscillator?

All wild ideas accepted... this is for a custom chip.

...Jim Thompson


How many wires will the chip have? 1 or 2?


--

John Larkin Highland Technology, Inc
picosecond timing laser drivers and controllers

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

  #8   Report Post  
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
external usenet poster
 
Posts: 2,181
Default Oscillator Proposal

On Sat, 14 Mar 2015 13:55:55 -0700, John Larkin
wrote:

On Sat, 14 Mar 2015 10:07:50 -0700, Jim Thompson
wrote:

Oscillator Proposal...

Suppose I have a series RLC, one end grounded, the other end driven by
a chip, how might I make that into an oscillator?

All wild ideas accepted... this is for a custom chip.

...Jim Thompson


How many wires will the chip have? 1 or 2?


Only one for the tank.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
  #9   Report Post  
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
external usenet poster
 
Posts: 231
Default Oscillator Proposal

On Sat, 14 Mar 2015 15:13:25 -0700, Jim Thompson
wrote:

On Sat, 14 Mar 2015 13:55:55 -0700, John Larkin
wrote:

On Sat, 14 Mar 2015 10:07:50 -0700, Jim Thompson
wrote:

Oscillator Proposal...

Suppose I have a series RLC, one end grounded, the other end driven by
a chip, how might I make that into an oscillator?

All wild ideas accepted... this is for a custom chip.

...Jim Thompson


How many wires will the chip have? 1 or 2?


Only one for the tank.

...Jim Thompson


OK, you can't do a parallel LC?


--

John Larkin Highland Technology, Inc
picosecond timing laser drivers and controllers

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

  #10   Report Post  
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
external usenet poster
 
Posts: 2,181
Default Oscillator Proposal

On Sat, 14 Mar 2015 15:39:13 -0700, John Larkin
wrote:

On Sat, 14 Mar 2015 15:13:25 -0700, Jim Thompson
wrote:

On Sat, 14 Mar 2015 13:55:55 -0700, John Larkin
wrote:

On Sat, 14 Mar 2015 10:07:50 -0700, Jim Thompson
wrote:

Oscillator Proposal...

Suppose I have a series RLC, one end grounded, the other end driven by
a chip, how might I make that into an oscillator?

All wild ideas accepted... this is for a custom chip.

...Jim Thompson

How many wires will the chip have? 1 or 2?


Only one for the tank.

...Jim Thompson


OK, you can't do a parallel LC?


I'm pondering. I need a high circulating current in the inductor.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.


  #11   Report Post  
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
external usenet poster
 
Posts: 13
Default Oscillator Proposal

On 15/03/2015 4:07 AM, Jim Thompson wrote:
Oscillator Proposal...

Suppose I have a series RLC, one end grounded, the other end driven by
a chip, how might I make that into an oscillator?

All wild ideas accepted... this is for a custom chip.


It could be the serial version of the Baxandall Class-D oscillator.

http://sophia-elektronica.com/0344_001_Baxandal.pdf

Tony Williams and I discussed this here some years ago - before Tony
died. Driving a tank circuit with a square wave via an inductor implies
peak voltage that go outside the rails by pi/2.

You can cut the amplitude (and reduce the third harmonic content of the
excitation current to zero with a perfect drive) by contriving to make
the drive voltage a "modified sine wave" which is to say a three-level
rectangular wave that sits at 0V for a third of the time - the drive is
low for one third of the period, centred of one sixth of the period,
high for one third of the period and again centred for the last sixth of
the period.

Don Lancaster's "magic sines" take the idea further.

--
Bill Sloman, Sydney



  #12   Report Post  
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
external usenet poster
 
Posts: 488
Default Oscillator Proposal

Jim Thompson wrote:
Oscillator Proposal...

Suppose I have a series RLC, one end grounded, the other end driven by
a chip, how might I make that into an oscillator?

All wild ideas accepted... this is for a custom chip.

...Jim Thompson

1) Ground resistor, feedback is at the top of the resistor, chip drive
at top of LCR; micro does the dirty work to make this stupidity work.
2) Try opamp, positive feedback output to NI via the R, with LC from NI
to gnd; standard resistive FB OP to INV; fiddle on values.




  #13   Report Post  
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.basics
external usenet poster
 
Posts: 732
Default Oscillator Proposal

On Sat, 14 Mar 2015 10:07:50 -0700, Jim Thompson
wrote:

Oscillator Proposal...

Suppose I have a series RLC, one end grounded, the other end driven by
a chip, how might I make that into an oscillator?

All wild ideas accepted... this is for a custom chip.

...Jim Thompson



ok, ok, putting noise through the narrowband passband was NOT a good idea
for making a 'clean' oscillator source.

So use the fact that there's a lot of 'logic' potential inside a chip, but
external connections cost a fortune...what's wrong with a set of two
variable, switchable current sources? One source, one sink to GND driving
the RLC node? The idea is to start out with very small current ramp up
until reach voltage near rail, switch OFF and turn on he other current
source, and head back down, near GND [or neg rail] reverse etc. Now
increase the current and keep doing until the voltage turns around on its
own BEFORE it reaches the voltage switch points. Make up an appropriate
rule.

maybe reverse process starrt at high current and come down in current. But
with enough stuff inside the chip, and coming up with appropriate rules,
you should be able to make a nice clean, stable output based upon looking
like a Function Generator output that is a bit independentof the Q of the
external tank.

Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Name that oscillator. ian field[_2_] Electronic Schematics 8 August 26th 08 07:45 PM
CD4060 oscillator, max resistor value (From SED) - Oscillator-ModifiedOldStyleCMOS.pdf Jim Thompson Electronic Schematics 25 August 7th 07 10:32 PM
LC Oscillator Anthony Fremont Electronic Schematics 11 March 25th 07 03:34 PM
LC Oscillator Anthony Fremont Electronic Schematics 0 March 19th 07 05:24 PM
LC Oscillator Anthony Fremont Electronic Schematics 0 March 19th 07 05:24 PM


All times are GMT +1. The time now is 10:57 PM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"