Things to avoid when using voltage regulators?Power Supply Design - Multiple Voltage RegulatorsConnecting several power regulators to a single voltage inputUsing Linear Voltage Regulators in Series?Different power sources for pcbEnsuring common ground in a circuit with several voltage requirementsWhy do linear voltage regulators have minimum output voltage > 0 VPower circuit with several voltage regulators — design rulesthe proper way to wire up multiple supply railscan I use Two Same Power supply sharing input in single circuit?Power source project
Why Shazam when there is already Superman?
What does "Scientists rise up against statistical significance" mean? (Comment in Nature)
Store Credit Card Information in Password Manager?
Can I sign legal documents with a smiley face?
Why did the EU agree to delay the Brexit deadline?
Loading commands from file
Lowest total scrabble score
New brakes for 90s road bike
Did arcade monitors have same pixel aspect ratio as TV sets?
Is (0,1] a closed or open set?
Is there any references on the tensor product of presentable (1-)categories?
How do you respond to a colleague from another team when they're wrongly expecting that you'll help them?
What is Cash Advance APR?
Is Witten's Proof of the Positive Mass Theorem Rigorous?
What was this official D&D 3.5e Lovecraft-flavored rulebook?
Infinite dials to reset ever?
What percentage of fillings performed today are done with mercury amalgam?
Travelling outside the UK without a passport
Is there a RAID 0 Equivalent for RAM?
Strong empirical falsification of quantum mechanics based on vacuum energy density
Open a doc from terminal, but not by its name
What is this called? Old film camera viewer?
How to indicate a cut out for a product window
Yosemite Fire Rings - What to Expect?
Things to avoid when using voltage regulators?
Power Supply Design - Multiple Voltage RegulatorsConnecting several power regulators to a single voltage inputUsing Linear Voltage Regulators in Series?Different power sources for pcbEnsuring common ground in a circuit with several voltage requirementsWhy do linear voltage regulators have minimum output voltage > 0 VPower circuit with several voltage regulators — design rulesthe proper way to wire up multiple supply railscan I use Two Same Power supply sharing input in single circuit?Power source project
$begingroup$
My project has components that operate at 3 different voltages (9, 5 and 3.3). I would like to only deal with one power source. Is it alright to feed one 12 V power source to 3 voltage regulators? Is there a smarter way of getting everything powered from a common source? I want to avoid placing the components in series.
power-supply voltage-regulator
$endgroup$
|
show 4 more comments
$begingroup$
My project has components that operate at 3 different voltages (9, 5 and 3.3). I would like to only deal with one power source. Is it alright to feed one 12 V power source to 3 voltage regulators? Is there a smarter way of getting everything powered from a common source? I want to avoid placing the components in series.
power-supply voltage-regulator
$endgroup$
3
$begingroup$
Questions which seek a list of thoughts really don't fit the stack exchange model. You are right to realize that putting diverse loads in series is generally not workable outside of special cases given special consideration. When dropping 12v to 3.3v with a linear regulator, consider that this is only 22.5% efficient - if your load takes substantial current you will turn a lot of electricity into heat in the regulator.
$endgroup$
– Chris Stratton
Mar 12 at 19:08
$begingroup$
Another issue would be if all circuits share a common ground or not.
$endgroup$
– DrMoishe Pippik
Mar 12 at 19:12
$begingroup$
The PC industry has dealt with this issue long ago and standardized on feedforward tightly coupled single regulators sharing a common transformer with regulation on the main 5V supply and tight cross-regulation , load specs. But what are your specs?
$endgroup$
– Sunnyskyguy EE75
Mar 12 at 19:55
1
$begingroup$
@dandavis, "what wrong with having them in series" - it depends on required amperage of each rail. If you need 9V@100mA and 3.3V@5A, it is uneconomical to make 9V@3A regulator before the 3.3V one (I assume switchers, even if smaller Vout/Vin ratio is somewhat more efficient).
$endgroup$
– Ale..chenski
Mar 12 at 20:53
1
$begingroup$
If the three circuits that need separate power supplies do not have one common power lead, whether positive or negative, using a single 12 V source would be problematic.
$endgroup$
– DrMoishe Pippik
Mar 14 at 0:46
|
show 4 more comments
$begingroup$
My project has components that operate at 3 different voltages (9, 5 and 3.3). I would like to only deal with one power source. Is it alright to feed one 12 V power source to 3 voltage regulators? Is there a smarter way of getting everything powered from a common source? I want to avoid placing the components in series.
power-supply voltage-regulator
$endgroup$
My project has components that operate at 3 different voltages (9, 5 and 3.3). I would like to only deal with one power source. Is it alright to feed one 12 V power source to 3 voltage regulators? Is there a smarter way of getting everything powered from a common source? I want to avoid placing the components in series.
power-supply voltage-regulator
power-supply voltage-regulator
asked Mar 12 at 19:03
DanielPatrickDanielPatrick
183
183
3
$begingroup$
Questions which seek a list of thoughts really don't fit the stack exchange model. You are right to realize that putting diverse loads in series is generally not workable outside of special cases given special consideration. When dropping 12v to 3.3v with a linear regulator, consider that this is only 22.5% efficient - if your load takes substantial current you will turn a lot of electricity into heat in the regulator.
$endgroup$
– Chris Stratton
Mar 12 at 19:08
$begingroup$
Another issue would be if all circuits share a common ground or not.
$endgroup$
– DrMoishe Pippik
Mar 12 at 19:12
$begingroup$
The PC industry has dealt with this issue long ago and standardized on feedforward tightly coupled single regulators sharing a common transformer with regulation on the main 5V supply and tight cross-regulation , load specs. But what are your specs?
$endgroup$
– Sunnyskyguy EE75
Mar 12 at 19:55
1
$begingroup$
@dandavis, "what wrong with having them in series" - it depends on required amperage of each rail. If you need 9V@100mA and 3.3V@5A, it is uneconomical to make 9V@3A regulator before the 3.3V one (I assume switchers, even if smaller Vout/Vin ratio is somewhat more efficient).
$endgroup$
– Ale..chenski
Mar 12 at 20:53
1
$begingroup$
If the three circuits that need separate power supplies do not have one common power lead, whether positive or negative, using a single 12 V source would be problematic.
$endgroup$
– DrMoishe Pippik
Mar 14 at 0:46
|
show 4 more comments
3
$begingroup$
Questions which seek a list of thoughts really don't fit the stack exchange model. You are right to realize that putting diverse loads in series is generally not workable outside of special cases given special consideration. When dropping 12v to 3.3v with a linear regulator, consider that this is only 22.5% efficient - if your load takes substantial current you will turn a lot of electricity into heat in the regulator.
$endgroup$
– Chris Stratton
Mar 12 at 19:08
$begingroup$
Another issue would be if all circuits share a common ground or not.
$endgroup$
– DrMoishe Pippik
Mar 12 at 19:12
$begingroup$
The PC industry has dealt with this issue long ago and standardized on feedforward tightly coupled single regulators sharing a common transformer with regulation on the main 5V supply and tight cross-regulation , load specs. But what are your specs?
$endgroup$
– Sunnyskyguy EE75
Mar 12 at 19:55
1
$begingroup$
@dandavis, "what wrong with having them in series" - it depends on required amperage of each rail. If you need 9V@100mA and 3.3V@5A, it is uneconomical to make 9V@3A regulator before the 3.3V one (I assume switchers, even if smaller Vout/Vin ratio is somewhat more efficient).
$endgroup$
– Ale..chenski
Mar 12 at 20:53
1
$begingroup$
If the three circuits that need separate power supplies do not have one common power lead, whether positive or negative, using a single 12 V source would be problematic.
$endgroup$
– DrMoishe Pippik
Mar 14 at 0:46
3
3
$begingroup$
Questions which seek a list of thoughts really don't fit the stack exchange model. You are right to realize that putting diverse loads in series is generally not workable outside of special cases given special consideration. When dropping 12v to 3.3v with a linear regulator, consider that this is only 22.5% efficient - if your load takes substantial current you will turn a lot of electricity into heat in the regulator.
$endgroup$
– Chris Stratton
Mar 12 at 19:08
$begingroup$
Questions which seek a list of thoughts really don't fit the stack exchange model. You are right to realize that putting diverse loads in series is generally not workable outside of special cases given special consideration. When dropping 12v to 3.3v with a linear regulator, consider that this is only 22.5% efficient - if your load takes substantial current you will turn a lot of electricity into heat in the regulator.
$endgroup$
– Chris Stratton
Mar 12 at 19:08
$begingroup$
Another issue would be if all circuits share a common ground or not.
$endgroup$
– DrMoishe Pippik
Mar 12 at 19:12
$begingroup$
Another issue would be if all circuits share a common ground or not.
$endgroup$
– DrMoishe Pippik
Mar 12 at 19:12
$begingroup$
The PC industry has dealt with this issue long ago and standardized on feedforward tightly coupled single regulators sharing a common transformer with regulation on the main 5V supply and tight cross-regulation , load specs. But what are your specs?
$endgroup$
– Sunnyskyguy EE75
Mar 12 at 19:55
$begingroup$
The PC industry has dealt with this issue long ago and standardized on feedforward tightly coupled single regulators sharing a common transformer with regulation on the main 5V supply and tight cross-regulation , load specs. But what are your specs?
$endgroup$
– Sunnyskyguy EE75
Mar 12 at 19:55
1
1
$begingroup$
@dandavis, "what wrong with having them in series" - it depends on required amperage of each rail. If you need 9V@100mA and 3.3V@5A, it is uneconomical to make 9V@3A regulator before the 3.3V one (I assume switchers, even if smaller Vout/Vin ratio is somewhat more efficient).
$endgroup$
– Ale..chenski
Mar 12 at 20:53
$begingroup$
@dandavis, "what wrong with having them in series" - it depends on required amperage of each rail. If you need 9V@100mA and 3.3V@5A, it is uneconomical to make 9V@3A regulator before the 3.3V one (I assume switchers, even if smaller Vout/Vin ratio is somewhat more efficient).
$endgroup$
– Ale..chenski
Mar 12 at 20:53
1
1
$begingroup$
If the three circuits that need separate power supplies do not have one common power lead, whether positive or negative, using a single 12 V source would be problematic.
$endgroup$
– DrMoishe Pippik
Mar 14 at 0:46
$begingroup$
If the three circuits that need separate power supplies do not have one common power lead, whether positive or negative, using a single 12 V source would be problematic.
$endgroup$
– DrMoishe Pippik
Mar 14 at 0:46
|
show 4 more comments
2 Answers
2
active
oldest
votes
$begingroup$
The problem of having multiple voltages to different parts of design has been solved by electronics industry with so-called multi-channel PMIC - Power management IC. Here is an example from Allegro A4490:
Or Texas Instruments TPS65400:
Here is an example (from my junk box) of how the power distribution block looks in reality (Proscan 4K 40" TV), using RT6914 PMIC:
This is a fairly common solution for many classes of devices: tablet/phones, TY-sets, set-top boxes, computer monitors, you name it. This is the standard technique.
Obviously a hybrid power topology is used, some regulators are in series, some are from parallel multi-channel PMIC. It should be remembered that the power-on and power-off sequencing usually has certain timing requirements, and a all-in-one single-IC PMIC has easier means to control the sequence.
Overall the topology of regulators depends on required amperage of each rail. If you need 9V@100mA and 3.3V@5A, it is uneconomical to make 9V@3A regulator before the 3.3V one (I assume switchers, even if smaller Vout/Vin ratio is somewhat more efficient). If you have a bunch of low-current consumers at low voltages while, say, the main power goes to 5V rail, then it is perfectly fine to have the other regulators fed from 5V rail. An example could be the "hybrid" power architecture of Intel ATOM SoC platform, Powering SoC.
$endgroup$
$begingroup$
Great answer. Thanks!
$endgroup$
– Leroy105
Mar 12 at 21:55
add a comment |
$begingroup$
To address the spirit of your question, yes it is acceptable to use a 12V "Bus" as an upstream supply for "LDO" regulators. This is necessarily done in vehicle/cessel design, albeit with healthy use of opto-isolation and filtering of unconditioned inputs to circuits.
It is also common to see this on Micro Controller programming boards, where 12V, 5V, 3.3V are all required and supplied from an upstream 15V. (High voltage Programmers for Microchip/Atmel devices.)
I would not "chain" them either. Modern buck converters, if used as an assembly, will not necessarily put a lot of HF back on that supply, but a cage might be an idea.
$endgroup$
add a comment |
Your Answer
StackExchange.ifUsing("editor", function ()
return StackExchange.using("mathjaxEditing", function ()
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix)
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["\$", "\$"]]);
);
);
, "mathjax-editing");
StackExchange.ifUsing("editor", function ()
return StackExchange.using("schematics", function ()
StackExchange.schematics.init();
);
, "cicuitlab");
StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "135"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);
else
createEditor();
);
function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader:
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
,
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);
);
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2felectronics.stackexchange.com%2fquestions%2f426945%2fthings-to-avoid-when-using-voltage-regulators%23new-answer', 'question_page');
);
Post as a guest
Required, but never shown
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
The problem of having multiple voltages to different parts of design has been solved by electronics industry with so-called multi-channel PMIC - Power management IC. Here is an example from Allegro A4490:
Or Texas Instruments TPS65400:
Here is an example (from my junk box) of how the power distribution block looks in reality (Proscan 4K 40" TV), using RT6914 PMIC:
This is a fairly common solution for many classes of devices: tablet/phones, TY-sets, set-top boxes, computer monitors, you name it. This is the standard technique.
Obviously a hybrid power topology is used, some regulators are in series, some are from parallel multi-channel PMIC. It should be remembered that the power-on and power-off sequencing usually has certain timing requirements, and a all-in-one single-IC PMIC has easier means to control the sequence.
Overall the topology of regulators depends on required amperage of each rail. If you need 9V@100mA and 3.3V@5A, it is uneconomical to make 9V@3A regulator before the 3.3V one (I assume switchers, even if smaller Vout/Vin ratio is somewhat more efficient). If you have a bunch of low-current consumers at low voltages while, say, the main power goes to 5V rail, then it is perfectly fine to have the other regulators fed from 5V rail. An example could be the "hybrid" power architecture of Intel ATOM SoC platform, Powering SoC.
$endgroup$
$begingroup$
Great answer. Thanks!
$endgroup$
– Leroy105
Mar 12 at 21:55
add a comment |
$begingroup$
The problem of having multiple voltages to different parts of design has been solved by electronics industry with so-called multi-channel PMIC - Power management IC. Here is an example from Allegro A4490:
Or Texas Instruments TPS65400:
Here is an example (from my junk box) of how the power distribution block looks in reality (Proscan 4K 40" TV), using RT6914 PMIC:
This is a fairly common solution for many classes of devices: tablet/phones, TY-sets, set-top boxes, computer monitors, you name it. This is the standard technique.
Obviously a hybrid power topology is used, some regulators are in series, some are from parallel multi-channel PMIC. It should be remembered that the power-on and power-off sequencing usually has certain timing requirements, and a all-in-one single-IC PMIC has easier means to control the sequence.
Overall the topology of regulators depends on required amperage of each rail. If you need 9V@100mA and 3.3V@5A, it is uneconomical to make 9V@3A regulator before the 3.3V one (I assume switchers, even if smaller Vout/Vin ratio is somewhat more efficient). If you have a bunch of low-current consumers at low voltages while, say, the main power goes to 5V rail, then it is perfectly fine to have the other regulators fed from 5V rail. An example could be the "hybrid" power architecture of Intel ATOM SoC platform, Powering SoC.
$endgroup$
$begingroup$
Great answer. Thanks!
$endgroup$
– Leroy105
Mar 12 at 21:55
add a comment |
$begingroup$
The problem of having multiple voltages to different parts of design has been solved by electronics industry with so-called multi-channel PMIC - Power management IC. Here is an example from Allegro A4490:
Or Texas Instruments TPS65400:
Here is an example (from my junk box) of how the power distribution block looks in reality (Proscan 4K 40" TV), using RT6914 PMIC:
This is a fairly common solution for many classes of devices: tablet/phones, TY-sets, set-top boxes, computer monitors, you name it. This is the standard technique.
Obviously a hybrid power topology is used, some regulators are in series, some are from parallel multi-channel PMIC. It should be remembered that the power-on and power-off sequencing usually has certain timing requirements, and a all-in-one single-IC PMIC has easier means to control the sequence.
Overall the topology of regulators depends on required amperage of each rail. If you need 9V@100mA and 3.3V@5A, it is uneconomical to make 9V@3A regulator before the 3.3V one (I assume switchers, even if smaller Vout/Vin ratio is somewhat more efficient). If you have a bunch of low-current consumers at low voltages while, say, the main power goes to 5V rail, then it is perfectly fine to have the other regulators fed from 5V rail. An example could be the "hybrid" power architecture of Intel ATOM SoC platform, Powering SoC.
$endgroup$
The problem of having multiple voltages to different parts of design has been solved by electronics industry with so-called multi-channel PMIC - Power management IC. Here is an example from Allegro A4490:
Or Texas Instruments TPS65400:
Here is an example (from my junk box) of how the power distribution block looks in reality (Proscan 4K 40" TV), using RT6914 PMIC:
This is a fairly common solution for many classes of devices: tablet/phones, TY-sets, set-top boxes, computer monitors, you name it. This is the standard technique.
Obviously a hybrid power topology is used, some regulators are in series, some are from parallel multi-channel PMIC. It should be remembered that the power-on and power-off sequencing usually has certain timing requirements, and a all-in-one single-IC PMIC has easier means to control the sequence.
Overall the topology of regulators depends on required amperage of each rail. If you need 9V@100mA and 3.3V@5A, it is uneconomical to make 9V@3A regulator before the 3.3V one (I assume switchers, even if smaller Vout/Vin ratio is somewhat more efficient). If you have a bunch of low-current consumers at low voltages while, say, the main power goes to 5V rail, then it is perfectly fine to have the other regulators fed from 5V rail. An example could be the "hybrid" power architecture of Intel ATOM SoC platform, Powering SoC.
edited Mar 12 at 23:03
answered Mar 12 at 19:25
Ale..chenskiAle..chenski
28.4k11866
28.4k11866
$begingroup$
Great answer. Thanks!
$endgroup$
– Leroy105
Mar 12 at 21:55
add a comment |
$begingroup$
Great answer. Thanks!
$endgroup$
– Leroy105
Mar 12 at 21:55
$begingroup$
Great answer. Thanks!
$endgroup$
– Leroy105
Mar 12 at 21:55
$begingroup$
Great answer. Thanks!
$endgroup$
– Leroy105
Mar 12 at 21:55
add a comment |
$begingroup$
To address the spirit of your question, yes it is acceptable to use a 12V "Bus" as an upstream supply for "LDO" regulators. This is necessarily done in vehicle/cessel design, albeit with healthy use of opto-isolation and filtering of unconditioned inputs to circuits.
It is also common to see this on Micro Controller programming boards, where 12V, 5V, 3.3V are all required and supplied from an upstream 15V. (High voltage Programmers for Microchip/Atmel devices.)
I would not "chain" them either. Modern buck converters, if used as an assembly, will not necessarily put a lot of HF back on that supply, but a cage might be an idea.
$endgroup$
add a comment |
$begingroup$
To address the spirit of your question, yes it is acceptable to use a 12V "Bus" as an upstream supply for "LDO" regulators. This is necessarily done in vehicle/cessel design, albeit with healthy use of opto-isolation and filtering of unconditioned inputs to circuits.
It is also common to see this on Micro Controller programming boards, where 12V, 5V, 3.3V are all required and supplied from an upstream 15V. (High voltage Programmers for Microchip/Atmel devices.)
I would not "chain" them either. Modern buck converters, if used as an assembly, will not necessarily put a lot of HF back on that supply, but a cage might be an idea.
$endgroup$
add a comment |
$begingroup$
To address the spirit of your question, yes it is acceptable to use a 12V "Bus" as an upstream supply for "LDO" regulators. This is necessarily done in vehicle/cessel design, albeit with healthy use of opto-isolation and filtering of unconditioned inputs to circuits.
It is also common to see this on Micro Controller programming boards, where 12V, 5V, 3.3V are all required and supplied from an upstream 15V. (High voltage Programmers for Microchip/Atmel devices.)
I would not "chain" them either. Modern buck converters, if used as an assembly, will not necessarily put a lot of HF back on that supply, but a cage might be an idea.
$endgroup$
To address the spirit of your question, yes it is acceptable to use a 12V "Bus" as an upstream supply for "LDO" regulators. This is necessarily done in vehicle/cessel design, albeit with healthy use of opto-isolation and filtering of unconditioned inputs to circuits.
It is also common to see this on Micro Controller programming boards, where 12V, 5V, 3.3V are all required and supplied from an upstream 15V. (High voltage Programmers for Microchip/Atmel devices.)
I would not "chain" them either. Modern buck converters, if used as an assembly, will not necessarily put a lot of HF back on that supply, but a cage might be an idea.
answered Mar 13 at 2:54
mckenzmmckenzm
1473
1473
add a comment |
add a comment |
Thanks for contributing an answer to Electrical Engineering Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2felectronics.stackexchange.com%2fquestions%2f426945%2fthings-to-avoid-when-using-voltage-regulators%23new-answer', 'question_page');
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
-power-supply, voltage-regulator
3
$begingroup$
Questions which seek a list of thoughts really don't fit the stack exchange model. You are right to realize that putting diverse loads in series is generally not workable outside of special cases given special consideration. When dropping 12v to 3.3v with a linear regulator, consider that this is only 22.5% efficient - if your load takes substantial current you will turn a lot of electricity into heat in the regulator.
$endgroup$
– Chris Stratton
Mar 12 at 19:08
$begingroup$
Another issue would be if all circuits share a common ground or not.
$endgroup$
– DrMoishe Pippik
Mar 12 at 19:12
$begingroup$
The PC industry has dealt with this issue long ago and standardized on feedforward tightly coupled single regulators sharing a common transformer with regulation on the main 5V supply and tight cross-regulation , load specs. But what are your specs?
$endgroup$
– Sunnyskyguy EE75
Mar 12 at 19:55
1
$begingroup$
@dandavis, "what wrong with having them in series" - it depends on required amperage of each rail. If you need 9V@100mA and 3.3V@5A, it is uneconomical to make 9V@3A regulator before the 3.3V one (I assume switchers, even if smaller Vout/Vin ratio is somewhat more efficient).
$endgroup$
– Ale..chenski
Mar 12 at 20:53
1
$begingroup$
If the three circuits that need separate power supplies do not have one common power lead, whether positive or negative, using a single 12 V source would be problematic.
$endgroup$
– DrMoishe Pippik
Mar 14 at 0:46