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X-reg voltage stabilizer LTSPICE file

Posted 15th March 2013 at 01:54 AM by rjm
Updated 20th March 2013 at 01:47 AM by rjm

I did up the X-reg circuit in LTSpice.

Results shown below, together with the LTSpice .asc file you can use to play around with this yourself.

First attached image shows FFT for the rectified DC (green), reference voltage (red) and X-reg output (blue) for the designed-for 10 mA output (top) and a more punishing 100 mA (bottom).

Second image shows an LTSpice screengrab for the LT1086 with bypassed adj pin under comparable loading. Input voltage in blue, output in green. This is a reasonable approximation of a "good" IC regulator.

Last image shows a plot of the exported LTSpice FFT data for the X-reg and the LT1086-12V (Cin 1000uF, Cout 100uF) both at nominal currents of 10 mA. The LT1086-12V is a reasonable substitute for a generic LM7812, i.e. a "bad" IC regulator.

A typical op amp will have sufficient PSRR to mop of the residual noise from the bypassed LT1086. The fixed LT1086-12V, on the other hand, puts out enough ripple to be impressed on the output of a typical audio op amp circuit.

The simulated results agree with my earlier models, no surprises. It simulates extremely well, but then again all "super-reg" circuits will perform impressively into a light, resistive load. Other than the op amp being used for the error amp being higher performance than than the one used in an IC, a discrete regulator circuit offers the freedom to use large electrolytics to filter the error amp's power supply as well as the voltage reference.

Ultimately though its all about whether they sound better or worse than an off-the-shelf integrated regulator IC. To my ears its no contest:X-reg wins!
Attached Thumbnails
Click image for larger version

Name:	xreg 01.png
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Name:	LT1086.png
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Name:	Regulator Comparison.png
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Attached Files
File Type: zip xreg 01.zip (1.9 KB, 257 views)
Views 4563 Comments 2
Total Comments 2


  1. Old Comment
    how result combination LT1086 + xreg ? it will be lower noise more ?
    Posted 9th June 2014 at 09:29 AM by oxoxbyx oxoxbyx is offline
  2. Old Comment
    rjm's Avatar
    No it won't. The x-reg output noise is already limited by the noise of the x-reg circuit itself.
    Posted 11th June 2014 at 06:15 AM by rjm rjm is offline

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