Power Supply help!
Merlin Zener
merlin at ion.com.au
Wed Feb 18 18:04:15 CET 1998
media at mail1.nai.net wrote:
>
> At 7:07 PM -0600 02/16/98, mymoog at ix.netcom.com wrote:
> >I hope the diagram comes out OK. I am wondering if the PS design is going
> >to be stable enough for the ASM1?
> >
> > 1 2
> > |------||| IN + |--|---|---|-------|--|----> out+
> > |PRI []|||--------|-------|--| | | | 7815 | |
> > _ | []||[] | | +- +- | | - C3
> > -| |--- 120v []||[]SEC | B1 | C1- C2- |----|--| -
> > -|_|--- 60Hz []||[] | | | | 3 | |
> > | []|||--------|-------|--| | | | |
> > |------||| IN - |--|---|--------|-----|----> out-
> > |
> > G
>
> As far as I can tell, this design would be inadequate for an ASM-1 because
> that would require a -/+ 15V supply -- this is only a +15V supply. You
> seem to just labeled the ground "-" (which would be the same for a
> single-sided supply).
>
> What I think you want is a supply with +15, -15 and ground. For this you
> need two regulators, in this case a 7815 and a 7915. 79xx regulators are
> the 78xx equivalents for negative voltages.
G'day guys,
here's something I came across in the archives - music machines, I think.
Digisound 80 +15V/-15V DC stabilised power supply
Specification:
output current 300mA per rail nominal, 450mA short circuit
(protected)
can be increased to 1A per rail
Components:
R1 1k8
R2 1R5 2.5W wirewound note this is one point five ohms
R3 3k3 metal film 100ppm TC or better
R4 3k0 metal film 100ppm TC or better
R5 1k2
R6 1k8
R7 1R5 2.5W wirewound note this is one point five ohms
R8 3k3 metal film 100ppm TC or better
R9 3k0 metal film 100ppm TC or better
R10 1k2
all other resistors 5% or better metal or carbon
film
RV1 1k cermet trimmer
RV2 1k cermet trimmer
C1 2200uF 35V electrolytic
C2 100nF polyester
C3 2u2 25V tantalum
C4 1nF polyester
C5 10uF 25V tantalum
C6 2200uF 35V electrolytic
C7 100nF polyester
C8 2u2 25V tantalum
C9 1nF polyester
C10 10uF 25V tantalum
IC1 uA723C or equivalent
IC2 uA723C or equivalent
Q1 TIP31A or equivalent
Q2 TIP31A or equivalent
LED1 any red LED
LED2 any red LED
FS1 1 amp fuse
FS2 1 amp fuse
BR1 1.6A 200V bridge rectifier or equivalent
BR2 1.6A 200V bridge rectifier or equivalent
Xformer secondaries 0:17V5, 0:17V5, 20VA
from "A"
>----o---o------------------+---o-c e ----+
| | | | \ /^ |
| | | | --- Q1 |
| | | | |b |
| | | | | |
| | +------------+ |
| | | 12 11 10| |
| | | | |
| | +-----+---|6 2|-----o-----+-------+--------> +15V
| | | | | | | | |
| | | |-| | | |-| | |-|
| | | | |R1| | | |R2 | | |R5
| | | | | | | | | | | |
| | | |-| | | |-| | |-|
| | | | | | | |+ |
| | | +---|5 3|-----o ===C5 |
| | | | | | --- |
| | | | | | | |
| | | | | |-| | |
| | | | | | |R3 | |
| | | | | | | | |
| | | | | | | | |
| | | | | |-| | |
| | | | | | | |
|+ | |+ | IC1 | | | |
=== | ===C3 | | |-| | |
--- | --- | | | | | |
|C1 | | | 4|-o->| |RV1 | |
| | | | | | | | | ---
| | | | | | |-| | \ /
| ---C2 | | 7 13 | | | | V LED1
| --- | +------------+ | | | ---
| | | | | | | | |
| | | | | | |-| | |
| | | | +-||-----+ | |R4 | |
| | | | C4 | | | |
| | | | |-| | |
| | | | | | |
>----o---o-----o-----------o---o------------o-----o-------o----> OV
from "B" | | |
--- | |
- | |
from "C" | |
>----o---o------------------+---o-c e ----+ | |
| | | | \ /^ | | |
| | | | --- Q2 | | |
| | | | |b | | |
| | | | | | | |
| | +------------+ | | |
| | | 12 11 10| | | |
| | | | | | |
| | +-----+---|6 2|-----o-----+-------+
| | | | | | | | |
| | | |-| | | |-| | |-|
| | | | |R6| | | |R7 | | |R10
| | | | | | | | | | | |
| | | |-| | | |-| | |-|
| | | | | | | |+ |
| | | +---|5 3|-----o ===C10 |
| | | | | | --- |
| | | | | |-| | |
| | | | | | |R8 | |
| | | | | | | | |
| | | | | | | | |
| | | | | |-| | |
| | | | | | | |
|+ | |+ | IC2 | | | |
=== | ===C8 | | |-| | |
--- | --- | | | | | |
|C6 | | | 4|-o->| |RV2 | |
| | | | | | | | | ---
| | | | | | |-| | \ /
| ---C7 | | 7 13 | | | | V LED2
| --- | +------------+ | | | ---
| | | | | | | | |
| | | | | | |-| | |
| | | | +-||-----+ | |R9 | |
| | | | C9 | | | |
| | | | |-| | |
| | | | | | |
>----o---o-----o-----------o----------------o-----o-------o--------> -15V
from "D"
17V5 AC
>------ ||| ---===--+
live ) ||| ) FS1 |
( ||| ( |
) ||| ) +-------+
( ||| ( | ~ |
) ||| ) | +|------> To "A"
( ||| ( | |
) ||| ) | BR1 |
( ||| ( | -|------> To "B"
) ||| ) | ~ |
( ||| ( +-------+
) ||| ) |
( ||| --------+ 0 AC
ground ) |||
>---+ ( ||| --===--+ 17V5 AC
| ) ||| ) FS2 |
| ( ||| ( |
--- ) ||| ) +-------+
- ( ||| ( | ~ |
) ||| ) | +|------> To "C"
( ||| ( | |
) ||| ) | BR2 |
( ||| ( | -|------> To "D"
) ||| ) | ~ |
( ||| ( +-------+
) ||| ) |
neutral ( ||| --------+ 0 AC
>----- ) |||
Transformer T1
Primary should match your local supply voltage. A double pole switch should
be connected on the live and neutral supply lines.
Notes:
C1 and C2 should be physically close together, as should C6 and C7.
R2 (and R7) determine the short circuit current limits. To double the
limit, halve these resistors. The power transistors Q1 and Q2 should be
mounted on heatsinks. If more than 1amp per rail is required, the
transistors
should be replaced with higher power types and appropriate heatsinks used.
As with any circuit which is designed to be connected to the local domestic
power supply, care must be taken in construction to ensure safety. It
is highly recommended that the ground connection is made, even with 110V
domestic supplies.
Whilst I have taken every care in transcribing this schematic, I won't
be held responsible for people electrocuting themselves!
The LEDs are optional, if they are not required, resistors R5 and R10
can be removed.
Setting up:
Adjust RV1 to give +15V from the positive output rail and RV2 to give
-15V from the negative output rail. Allow to warm up and repeat the
adjustments. Stable power supply rails are essential for proper operation
of voltage controlled synthesisers.
While this isn't the most modern power supply design in the world, it
is cheap and works well.
--
Merlin Zener mailto:merlin at ion.com.au
Piano and Synthesizer voice: (+61) (0) 418 779 594
Gold Coast, Australia http://www.ion.com.au/~merlin
"No-one ever went blind from looking on the bright side of life"
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