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The (Shunt-Source) S-Reg Voltage Regulator

Posted 19th December 2016 at 12:09 PM by rjm
Updated 4th May 2017 at 12:39 AM by rjm (added BOM)

S-reg voltage shunt-source regulator for line-level audio circuits.

This is designed to accept rectified 12x2 VAC input, producing +/-12 V output split rails.

Features soft-start and over-current protection, standard configurations for load currents up to 50 mA. High performance: 80 dB ripple rejection up to 100 kHz.

update: BOM uploaded
update: web page (stub)
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Attached Files
File Type: asc sreg10e.asc (5.0 KB, 125 views)
File Type: zip pcb-sreg-10f5-bom.zip (88.2 KB, 11 views)
Total Comments 2


  1. Old Comment
    dimkasta's Avatar
    I like that you use current parts and not some dodo

    Is the max load current a restriction of the circuit? Or we can do more if we beef-up the BJTs or add some heatsinks?
    Posted 19th December 2016 at 03:09 PM by dimkasta dimkasta is offline
  2. Old Comment
    rjm's Avatar

    As you know a shunt regulator draws the maximum current all the time, even with no load connected, so you have to think carefully before increasing it.

    If you heatsink Q3,4,5,6 and/or go with TO-220 package types for example it should be possible to adjust up to 200 mA. Anything more than that and the board will need a total redesign with more capacitance, larger resistors, etc. It can also be modified to run at higher voltages, though at proportionately lower current.

    The S-Reg is designed for low current circuits, specifically an op amp or equivalent based line level circuits like a preamp, phono stage, line driver, and similar. For these applications there is generally no need to have more than 50 mA on tap. Keeping the current limit low means I can get away with a smaller board and simpler BOM.
    Posted 19th December 2016 at 09:35 PM by rjm rjm is offline
    Updated 19th December 2016 at 09:40 PM by rjm

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