[sdiy] From a commercial standpoint -- has Eurorack "won"?

[Vladimir Pantelic]

On 03.05.2016 06:42, rsdio at audiobanshee.com wrote:
>
> On May 1, 2016, at 1:13 PM, Vladimir Pantelic <vladoman at gmail.com>
> wrote:
>> On 01.05.2016 21:32, neil harper wrote:
>>>> BTW, I liked how the Oberheim SEM used +/-18 V and then
>>>> regulated it down individually to +/- 15V. Also like how -15V
>>>> is mirror-regulated from +15V, which has its merits.
>>>
>>> Can I ask what "mirror-regulated" is and what the merits are?
>>
>> as I understand, mirror regulated means that the negative rail is
>> tied to the voltage of the positive one, so if for whatever reason
>> the positive supply goes away, the negative goes to zero too - and
>> vice versa. the benefit would be to never asymmetricaly supply a
>> circuit that needs a symmetric power supply and thus kill less
>> 2164s.
>
> There's one problem here. If the negative supply goes out, what makes
> the positive supply shut down? I've never seen a mirror supply
> circuit that actually has protection in both directions. If someone
> has a link to such a doubly-protected circuit, I'd be very interested
> to see it.

I've never seen a mirror supply circuit in any form, do you have some
reference link?

> Some supply chips have a "power good" output and "enable" inputs. I
> suppose that a mirrored negative supply could feed its "power good"
> output into the "enable" input of the positive supply, but that seems
> like it would create a chicken-and-egg problem. Which supply starts
> up first? If they both shut down when the other one fails, then how
> does the pair ever get started?

nothing a microcontroller and some clever software could not handle :)