Things to avoid when using voltage regulators?












3












$begingroup$


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.










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  • 2




    $begingroup$
    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
    5 hours ago












  • $begingroup$
    Another issue would be if all circuits share a common ground or not.
    $endgroup$
    – DrMoishe Pippik
    5 hours ago










  • $begingroup$
    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
    4 hours ago












  • $begingroup$
    what wrong with having them in series to help spread the heat?
    $endgroup$
    – dandavis
    4 hours ago










  • $begingroup$
    @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
    3 hours ago
















3












$begingroup$


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.










share|improve this question







New contributor




DanielPatrick is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$








  • 2




    $begingroup$
    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
    5 hours ago












  • $begingroup$
    Another issue would be if all circuits share a common ground or not.
    $endgroup$
    – DrMoishe Pippik
    5 hours ago










  • $begingroup$
    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
    4 hours ago












  • $begingroup$
    what wrong with having them in series to help spread the heat?
    $endgroup$
    – dandavis
    4 hours ago










  • $begingroup$
    @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
    3 hours ago














3












3








3





$begingroup$


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.










share|improve this question







New contributor




DanielPatrick is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$




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






share|improve this question







New contributor




DanielPatrick is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











share|improve this question







New contributor




DanielPatrick is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









share|improve this question




share|improve this question






New contributor




DanielPatrick is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









asked 5 hours ago









DanielPatrickDanielPatrick

161




161




New contributor




DanielPatrick is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.





New contributor





DanielPatrick is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






DanielPatrick is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.








  • 2




    $begingroup$
    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
    5 hours ago












  • $begingroup$
    Another issue would be if all circuits share a common ground or not.
    $endgroup$
    – DrMoishe Pippik
    5 hours ago










  • $begingroup$
    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
    4 hours ago












  • $begingroup$
    what wrong with having them in series to help spread the heat?
    $endgroup$
    – dandavis
    4 hours ago










  • $begingroup$
    @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
    3 hours ago














  • 2




    $begingroup$
    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
    5 hours ago












  • $begingroup$
    Another issue would be if all circuits share a common ground or not.
    $endgroup$
    – DrMoishe Pippik
    5 hours ago










  • $begingroup$
    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
    4 hours ago












  • $begingroup$
    what wrong with having them in series to help spread the heat?
    $endgroup$
    – dandavis
    4 hours ago










  • $begingroup$
    @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
    3 hours ago








2




2




$begingroup$
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
5 hours ago






$begingroup$
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
5 hours ago














$begingroup$
Another issue would be if all circuits share a common ground or not.
$endgroup$
– DrMoishe Pippik
5 hours ago




$begingroup$
Another issue would be if all circuits share a common ground or not.
$endgroup$
– DrMoishe Pippik
5 hours ago












$begingroup$
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
4 hours ago






$begingroup$
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
4 hours ago














$begingroup$
what wrong with having them in series to help spread the heat?
$endgroup$
– dandavis
4 hours ago




$begingroup$
what wrong with having them in series to help spread the heat?
$endgroup$
– dandavis
4 hours ago












$begingroup$
@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
3 hours ago




$begingroup$
@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
3 hours ago










1 Answer
1






active

oldest

votes


















7












$begingroup$

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:



enter image description here



Or Texas Instruments TPS65400:



enter image description here



Here is an example (from my junk box) of how the power distribution block looks in reality (Proscan 4K 40" TV), using RT6914 PMIC:



enter image description here



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.






share|improve this answer











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  • $begingroup$
    Great answer. Thanks!
    $endgroup$
    – Leroy105
    2 hours ago











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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









7












$begingroup$

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:



enter image description here



Or Texas Instruments TPS65400:



enter image description here



Here is an example (from my junk box) of how the power distribution block looks in reality (Proscan 4K 40" TV), using RT6914 PMIC:



enter image description here



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.






share|improve this answer











$endgroup$













  • $begingroup$
    Great answer. Thanks!
    $endgroup$
    – Leroy105
    2 hours ago
















7












$begingroup$

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:



enter image description here



Or Texas Instruments TPS65400:



enter image description here



Here is an example (from my junk box) of how the power distribution block looks in reality (Proscan 4K 40" TV), using RT6914 PMIC:



enter image description here



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.






share|improve this answer











$endgroup$













  • $begingroup$
    Great answer. Thanks!
    $endgroup$
    – Leroy105
    2 hours ago














7












7








7





$begingroup$

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:



enter image description here



Or Texas Instruments TPS65400:



enter image description here



Here is an example (from my junk box) of how the power distribution block looks in reality (Proscan 4K 40" TV), using RT6914 PMIC:



enter image description here



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.






share|improve this answer











$endgroup$



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:



enter image description here



Or Texas Instruments TPS65400:



enter image description here



Here is an example (from my junk box) of how the power distribution block looks in reality (Proscan 4K 40" TV), using RT6914 PMIC:



enter image description here



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.







share|improve this answer














share|improve this answer



share|improve this answer








edited 1 hour ago

























answered 5 hours ago









Ale..chenskiAle..chenski

28.2k11866




28.2k11866












  • $begingroup$
    Great answer. Thanks!
    $endgroup$
    – Leroy105
    2 hours ago


















  • $begingroup$
    Great answer. Thanks!
    $endgroup$
    – Leroy105
    2 hours ago
















$begingroup$
Great answer. Thanks!
$endgroup$
– Leroy105
2 hours ago




$begingroup$
Great answer. Thanks!
$endgroup$
– Leroy105
2 hours ago










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